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Is there a script to measure face width to height ratio?

Is there a script to measure face width to height ratio?


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I'd be interested whether you know a script or anything automated to measure the face width to height ratio of a set of pictures depicting faces.

Otherwise, your experience how to do that efficiently or a list of tools to do so easily is highly appreciated as well.


The Psychology of Beauty

Recent debate on female body attractiveness has centered around the relative contributions of body-mass index (weight/height 2 : BMI) and waist-hip ratio (circumference of narrowest part of waist/circumference of widest part of hips/buttocks: WHR) on evaluations of female body attractiveness. The results from direct comparisons are consistent: BMI influences attractiveness ratings more than WHR.

Using scanned, rotating 3D images of Caucasian female figures as stimuli and attractiveness ratings made by Chinese students, Fan and colleagues (2004) published the following scatter plot (these plots show the male ratings only – there was no significant difference in the female ratings) of WHR and attractiveness rating (AR):

Several things are apparent:

Having created 3D scans of their stimuli, Fan and colleagues were able to calculate the actual volume of each woman’s body. This calculation enabled them to introduce a third ratio: volume height index (body volume/chin height 2 : VHI). Given that BMI is an inexact estimate of body size/shape, it is likely that a more precise ratio: like body volume and height (at the chin) would predict attractiveness more precisely than BMI. And this is exactly what was found: Log(VHI) accounted for approximately 90% of the variance in attractiveness ratings in this study. A subsequent study (Fan et.al., 2007), that included digitally created, low-VHI bodies found the optimal female volume/height index to be approximately 14 liters/meter 2 .

Other factors contribute to female body attractiveness: leg length, waist, hip, and bust proportions, but these features seem to enter raters’ consideration after a preliminary analysis of body size.

Current data does suggest that size cues take priority over secondary sexual characteristic cues in evaluations of body attractiveness. It is tempting to suggest that size matters more than shape in evaluating female body attractiveness – but any statement of this sort would be premature. It is unlikely that perceivers estimate body size without utilizing shape cues and unclear what role secondary sexual characteristic cues play in this estimate. Perhaps eye-tracking studies are an appropriate next step?


Fan, J., Liu, F., Wu, J., & Dai, W. (2004). Visual perception of female physical attractiveness Proceedings of the Royal Society B: Biological Sciences, 271 (1537), 347-352 DOI: 10.1098/rspb.2003.2613

Fan, J., Dai, W., Quan, X., Chau, K., & Liu, Q. (2007). Effects of shape parameters on the attractiveness of a female body. Perceptual and Motor Skills, 105, 117-132 PMID: 17918555


Summary

In this blog post, we learned how to measure the size of objects in an image using Python and OpenCV.

Just like in our tutorial on measuring the distance from a camera to an object, we need to determine our “pixels per metric” ratio, which describes the number of pixels that can “fit” into a given number of inches, millimeters, meters, etc.

To compute this ratio, we need a reference object with two important properties:

  • Property #1: The reference object should have known dimensions (such as width or height) in terms of a measurable unit (inches, millimeters, etc.).
  • Property #2: The reference object should be easy to find, either in terms of location of the object or in its appearance.

Provided that both of these properties can be met, you can utilize your reference object to calibrate your pixels_per_metric variable, and from there, compute the size of other objects in an image.

In our next blog post, we’ll take this example a step further and learn how to compute the distance between objects in an image.

Be sure to signup for the PyImageSearch Newsletter using the form below to be notified when the next blog post goes live — you won’t want to miss it!

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About the Author

Hi there, I’m Adrian Rosebrock, PhD. All too often I see developers, students, and researchers wasting their time, studying the wrong things, and generally struggling to get started with Computer Vision, Deep Learning, and OpenCV. I created this website to show you what I believe is the best possible way to get your start.


Why does it matter?

At this point, you’re probably thinking, “Well that’s some lovely nit-picking nerdery there, Derek – but why does it matter?”. That’s a good question. And there’s a good answer.

The reason it’s important to understand the levels of measurement in your data – nominal, ordinal, interval and ratio – is because they directly impact which statistical techniques you can use in your analysis. Each statistical test only works with certain types of data. Some techniques work with categorical data (i.e. nominal or ordinal data), while others work with numerical data (i.e. interval or ratio data) – and some work with a mix. While statistical software like SPSS or R might “let” you run the test with the wrong type of data, your results will be flawed at best, and meaningless at worst.

The takeaway – make sure you understand the differences between the various levels of measurement before you decide on your statistical analysis techniques. Even better, think about what type of data you want to collect at the survey design stage (and design your survey accordingly) so that you can run the most sophisticated statistical analyses once you’ve got your data.


The Golden Ratio

So, the more a body fits into the parameters laid out by the golden ratio, the more attractive it will be, both physiologically and psychologically. It's a really interesting bit of science and evolutionary psychology, and it begs the question: How do we use this information to help you achieve your fitness goals and get the body that you want?

Well, the first thing is to realize that, chances are, the body you are working so hard for is based on our intrinsic ideas of symmetry. Of course, the numbers are just everywhere in places we can't control. Thankfully, not many women are going to be looking closely enough at your feet and shins to make sure they add up correctly.

That said, the golden ratio also applies heavily in places we can control, and the most important one by far is the most visible: your waist-to-shoulder measurement. As mentioned earlier, broad shoulders imply strength, power and virility, and are, therefore, a mating qualifier that makes a body appear more attractive to the opposite sex. But &ldquobroad&rdquo is a relative term. Something can only be &ldquobroad&rdquo if it&rsquos compared to something less so, which is where your shoulder-to-waist measurement (and the golden ratio) come in.

The Adonis Index: How Do You Measure Up

Now, let&rsquos say you&rsquore a skinny guy looking to gain some muscle. If your waist measures 28 inches, then your goal for your shoulders should be just about 45.3 inches. Even if you don&rsquot immediately gain a tremendous amount of muscle, as long as you develop your shoulders to fit that proportion, you&rsquore on your way to a &ldquoperfect&rdquo body.

Alternatively, let&rsquos say you&rsquore on the bigger side and you want to drop some weight. Maybe your shoulders measure 54 inches around &mdash quite a big guy, and certainly powerful looking &mdash but your waist could use some help. In this case, all you need to do is drop enough weight to bring your waist measurement down to around 33.5, and your proportions will be immediately more attractive. That means, you don&rsquot need to get &ldquosuper lean&rdquo just to improve your body and improve your Adonis Index.

A Case Study

If he diets down a bit and brings his waist measurement down to 32, his measurement will jump to 1.406. That means without increasing his muscle mass at all, a mere two-inch reduction in his waist has brought him a lot closer to an ideal Adonis Index and an improved body.

If this client wants to take it a step further, he can adjust his training workout to add size to his shoulders. If he can add three inches on the total circumference, he&rsquos pretty much set. At 48 inches with a 32 waist, our client is now at an Index 1.5, which is amazingly close.

Put It In Action

If you're trying to build an impressive body &mdash with strong, broad shoulders and a narrow waist &mdash you definitely want to pay careful attention to the golden ratio and to your Adonis Index. The perfect body may be closer than you think.

Next Steps:
1- Determine your goal: fat loss or muscle building?
2- If it's fat loss, measure your shoulders. If muscle building, measure your waist.
3- If you&rsquore trying to lose fat, focus on getting your waist measurement to fit the Adonis Index, as determined by your shoulder measurement. If you&rsquore trying to gain muscle, focus on developing your shoulders to be 1.618 times your waist measurement.

Let us know how far away from your goal you are in the comments field below.


In your face: facial metrics predict aggressive behaviour in the laboratory and in varsity and professional hockey players

Facial characteristics are an important basis for judgements about gender, emotion, personality, motivational states and behavioural dispositions. Based on a recent finding of a sexual dimorphism in facial metrics that is independent of body size, we conducted three studies to examine the extent to which individual differences in the facial width-to-height ratio were associated with trait dominance (using a questionnaire) and aggression during a behavioural task and in a naturalistic setting (varsity and professional ice hockey). In study 1, men had a larger facial width-to-height ratio, higher scores of trait dominance, and were more reactively aggressive compared with women. Individual differences in the facial width-to-height ratio predicted reactive aggression in men, but not in women (predicted 15% of variance). In studies 2 (male varsity hockey players) and 3 (male professional hockey players), individual differences in the facial width-to-height ratio were positively related to aggressive behaviour as measured by the number of penalty minutes per game obtained over a season (predicted 29 and 9% of the variance, respectively). Together, these findings suggest that the sexually dimorphic facial width-to-height ratio may be an ‘honest signal’ of propensity for aggressive behaviour.

1. Introduction

Most studies that have investigated facial characteristics and sexual selection have focused on what is perceived as attractive to an observer (Rhodes 2006). Some evidence suggests that certain facial judgements may reflect inherent processing mechanisms in that newborns' preferences for faces parallel those of adults (e.g. Langlois et al. 1987 Slater et al. 2000). Although judgements of attractiveness also are influenced by experience (e.g. Peskin & Newell 2004), perception of attractiveness is thought be part of human evolutionary heritage, perhaps as an honest signal of health (Thornhill & Gangestad 1999). Sexual dimorphism in the face is one such signal that may have been shaped by intra- and intersexual selection (Little et al. 2008). For instance, men with masculine facial features may have obtained increased access to valued resources (i.e. resources important for survival and reproduction) because they are regarded as socially and physically dominant by their rivals (Mueller & Mazur 1996 Swaddle & Reierson 2002). Also, facial masculinity is generally found attractive in men, perhaps serving as an honest signal of health (Rhodes 2006 Rhodes et al. 2007). Further, a recent study found a positive correlation between salivary testosterone concentrations and ratings of facial masculinity (Penton-Voak & Chen 2004). The immunocompetence handicap hypothesis posits that testosterone is responsible for the development of male secondary sex traits (e.g. facial masculinity), but it also has a negative impact on the immune system (Folstad & Karter 1992). Therefore, only high-quality (i.e. healthy, good ‘genes’) men can afford to display these characteristics without suffering the costs of parasite loads (Folstad & Karter 1992).

In addition to providing information as to the personality and health of a target, some recent studies suggest that characteristics of the face may also provide cues as to the behavioural tendencies of the target. For example, women's judgements of the extent to which a man was interested in infants based on his face predicted his actual interest in infants (as measured in a laboratory task Roney et al. 2006). Raters' judgements of facial masculinity (Rhodes et al. 2005) and dominance (Mazur et al. 1994) predicted sexual behaviour of men. People also show some accuracy at identifying ‘cheaters’ in a Prisoner's Dilemma game based on facial photographs (Verplaetse et al. 2007). Together, these findings suggest that people can make accurate inferences about others' personality traits and behavioural dispositions based on certain signals conveyed by the face. The precise facial metrics used to make these trait judgements are not well understood (Danel & Pawlowski 2007). Recently, Weston et al. (2007) described the facial width-to-height ratio, a sexual dimorphism in the structure of the face that was independent of body size, from a morphometric analysis of an ontogenetic series of skulls. In brief, males and females were found to have different growth trajectories that diverge at puberty for bizygomatic width and not for upper facial height, leading to a width-to-height facial dimorphism (greater ratio in men than in women) that is independent of increased body size. The sex difference in the facial width-to-height ratio emerged around puberty, which is when sex differences in facial structure related to body size appear, in part due to increased testosterone concentrations at puberty in boys (Verdonck et al. 1999). Thus, the sexual dimorphism in facial width-to-height may reflect a sexual selection pressure that is independent of selection for body size.

Here, we conducted three studies to examine the extent to which the face width-to-height ratio predicted dominance and aggressive behaviour. In study 1, we first examined whether the facial width-to-height sexual dimorphism, previously described in skulls (Weston et al. 2007), can be found in the photographs of faces. We also investigated the extent to which within-sex variability in the width-to-height ratio in the upper face was associated with within-sex variability in a sexually dimorphic personality trait, dominance, and in behavioural aggression. Dominance and aggression were chosen as measures because facial signals of dominance and/or aggression may not only influence mate preference (intersexual selection), but may also be important signals moderating intermale behaviour (intrasexual selection). For studies 2 and 3, we examined whether a relationship between individual differences in the facial width-to-height ratio would predict aggressive behaviour outside of a laboratory setting. The association between facial width-to-height ratio and aggressive behaviour (defined as the number of penalty minutes obtained per game) was tested in male varsity hockey players (study 2) and in professional ice hockey (Canadian teams in the National Hockey League (NHL) study 3).

2. Material and methods

(a) Participants

In study 1, 88 undergraduate students (37 men and 51 women mean age=18.98 years, s.d.=1.15) took part for course credit and a $5 honorarium. Eighty-two per cent of the participants self-identified as Caucasian, with the remaining 18 per cent representing a diversity of ethnicities. All procedures of the study were approved by the university's ethical review committee.

(b) Face ratios

In study 1, photographs were taken with a Nikon D50 digital camera. ImageJ (NIH open-source software) was used to measure the distance between the lip and brow (height of upper face) and the left and right zygion (bizygomatic width) of the digitized images, based on Weston et al. (2007 figure 1). Inter-rater reliability was high for all measures (distance between left and right zygion: r=0.996, p<0.001 distance between the lip and brow: r=0.989, p<0.001 width-to-height ratio: r=0.985, p<0.001).

Figure 1 An example of the measures used for facial width-to-height ratio. Vertical lines represent the distance between the left and the right zygion (bizygomatic width). Horizontal lines represent the distance between the upper lip and brow (upper facial height).

For study 2, photographs were obtained from 21 undergraduate male varsity hockey players (mean age=22.81 years, s.d.=1.29) from the university's website (all players whose pictures were available except for goalkeepers because these individuals are typically not in a position to obtain penalties, the measure of aggression) and measured as in study 1. All the pictures were facing forward however, some individuals did not have a neutral expression (i.e. some were smiling). All measurements had good inter-rater reliability (facial height: r=0.98, p<0.001 facial width: r=0.94, p<0.001 width-to-height ratio: r=0.90, p<0.001).

For study 3, photographs were obtained for every player who played on the Canadian teams of the NHL during the 2007–2008 season (Calgary Flames, Edmonton Oilers, Montreal Canadiens, Ottawa Senators, Toronto Maple Leafs and Vancouver Canucks) whose pictures were available on the Entertainment and Sports Programming Network (ESPN) website (n=126). Two pictures had to be excluded because the individuals were not facing forward and the tilt of the head would compromise the measurement of the facial width-to-height ratio. Further, we excluded photographs from goalkeepers (n=12) because these individuals are typically not in a position to obtain penalties (the measure of aggression). The final sample was n=112. Facial width-to-height ratios were calculated as in studies 1 and 2. All measurements had good inter-rater reliability (facial height: r=0.97, p<0.001 facial width: r=0.996, p<0.001 width-to-height ratio: r=0.96, p<0.001).

(c) Trait dominance

Participants completed a 10-item questionnaire assessing trait dominance (International Personality Item Pool scales Goldberg et al. 2006). Some examples of items include ‘Like having authority over others’ and ‘Want to be in charge’. Responses were scored on a Likert scale ranging from −2 (very inaccurate) to +2 (very accurate), and had high reliability (Cronbach's alpha=0.82).

(d) Point Subtraction Aggression Paradigm

To measure aggressive behaviour, we used a modified version of the Point Subtraction Aggression Paradigm (PSAP Cherek 1981). This measure is positively correlated with various self-report measures of aggression (Gerra et al. 2007 Golomb et al. 2007). In brief (see also Carré & McCormick 2008), participants were led to believe that they would be paired with a same-sex partner (in actuality, an E-Prime computer program) on a task that required them to select among three response options to earn points that would be exchangeable for money. Pressing response option no. 1 a hundred consecutive times would cause the point counter on the screen to enlarge, flash several times with positive signs around it, and increase the point counter total by one. It was explained to participants that the point counter might flash several times with negative signs around it, resulting in a one-point decrease in the point counter total. They were told that this meant that their partner (actually the computer program) had stolen a point, and each stolen point would be added to the partner's counter. Participants could respond by continuing to select option no. 1 (point reward) or could switch to option no. 2 or 3. Pressing option no. 2 ten times would steal a point from their partner however, participants were instructed that they were randomly assigned to the experimental condition whereby they, unlike their partner, would not keep any points stolen. Pressing option no. 3 ten times would protect their point counter against theft of points for a brief time. Thus, the dependent variables from the PSAP measure were option nos. 1 (reward earned), 2 (aggression) and 3 (protection). Selection of option no. 2 was considered reactive aggression because the participants did not increase reward, and in fact lost opportunity to increase reward, each time option no. 2 was selected.

(e) Study 1 procedure

Participants arrived in groups of two or four and first completed a demographic and trait dominance questionnaire. Next, participants were photographed while in a seated position and maintaining a neutral facial expression. Participants were escorted to separate rooms for the PSAP procedure. The PSAP took approximately 40 min to complete, after which they completed a brief questionnaire designed to assess whether they were aware of the deception used in the experiment. Responses confirmed that participants believed that they were playing against another person.

(f) Aggression measure in studies 2 and 3

The penalty minutes that each player accrued per number of games played during the 2007–2008 season (obtained from the Ontario University Athletics website for study 2 and from ESPN's website for study 3) were used as the measure of aggression. Penalties included behaviours such as slashing, cross-checking, high-sticking, boarding, elbowing, checking from behind, fighting and so on. These behaviours meet the classic definition of aggressive behaviour as any act that is intended to harm another individual, who, in turn, is motivated to avoid the behaviour (Baron & Richardson 1994).

(g) Statistics

Gender differences in trait dominance and facial width-to-height ratio were examined using multivariate analysis of variance (MANOVA), with follow-up t-tests. Multiple linear regression analysis was used to examine the relationship between predictor variables (trait dominance, facial width-to-height ratio and trait dominance by facial width-to-height ratio interaction) and aggressive behaviour as measured by the PSAP. The main assumptions underlying linear regression (e.g. outliers, linear relationship between predictors and criterion, multicollinearity, independence of observations, homoscedasticity and errors normally distributed) were examined and were all met. Also, Pearson's correlation coefficients were computed to examine the bivariate association between the facial width-to-height ratio and aggressive behaviour in varsity and professional ice hockey players. All analyses conducted were two-tailed and the level of significance was set at p<0.05.

3. Results

(a) Study 1

Tests for gender differences in trait dominance, facial ratio and aggressive behaviour consisted of MANOVA and follow-up t-tests. There was a main effect of gender (F5,82=3.04, p=0.01): men had a greater facial ratio (t86=2.33, p=0.02, Cohen's d=0.50) scored higher on trait dominance (t86=2.15, p=0.04, Cohen's d=0.46) and were more aggressive than women (t86=2.18, p=0.03, Cohen's d=0.47). Men and women did not differ in reward (t86=−0.80, p=0.43, Cohen's d=0.18) or protection (t86=0.66, p=0.51, Cohen's d=0.15) responses (table 1).

Table 1 Mean (s.e.m.) for women (n=51) and men (n=37) for each of the variables measured in study 1.

Separate regression analyses for men and women were computed with trait dominance and face ratio as predictors of aggressive behaviour. For men, face ratio predicted 15 per cent of unique variance in aggressive behaviour (R 2 =0.18, F2,34=3.60, p=0.04 t36=2.50, p=0.02 figure 2), but trait dominance was not a significant predictor of aggression (p=0.27). Furthermore, the face ratio by trait dominance interaction was not significant (Rchange 2 =0.001, F1,33=0.04, p=0.84). For women, face ratio and trait dominance did not predict aggressive behaviour (R 2 =0.03, F2,41=0.66, p=0.52), nor did the interaction (Rchange 2 =0.003, F1,40=0.14, p=0.72).

Figure 2 Scatter plot depicting the relationship between face width-to-height ratio and aggressive behaviour in undergraduate men (n=37, r=0.38 and p=0.02).

(b) Study 2

Individual differences in face ratio in male hockey players explained 29.2 per cent of the variance in penalty minutes per game played (r=0.54, p=0.01 figure 3).

Figure 3 Scatter plot depicting the relationship between face width-to-height ratio and aggressive behaviour (penalty minutes per game) in male varsity hockey players (n=21, r=0.54 and p=0.01).

(c) Study 3

Individual differences in the face width-to-height explained a significant proportion of the variance in aggressive behaviour (r=0.30, p=0.005) in NHL hockey players. Separate correlation coefficients were also computed for each individual team (figure 4). All correlation coefficients were in the positive direction and ranged from 0.17 to 0.51.

Figure 4 Scatter plots depicting the relationship between face width-to-height ratio and aggressive behaviour (number of penalty minutes per game played) in male professional hockey players for the six Canadian teams in the NHL (n=112) as a group (a) and for each individual team (bg): (a) all Canadian NHL teams (r=0.30), (b) Calgary Flames (r=0.17), (c) Edmonton Oilers (r=0.20), (d) Montreal Canadiens (r=0.39), (e) Ottawa Senators (r=0.51), (f) Toronto Maple Leafs (r=0.37) and (g) Vancouver Canucks (r=0.24).

4. Discussion

In sum, a sexually dimorphic width-to-height ratio (men>women) in the upper face was evident in the photographs of an unselected sample of undergraduates, and this ratio predicted aggression in men assessed in a validated laboratory behavioural task and in a naturalistic setting (varsity and professional ice hockey players). Weston et al. (2007) first reported the sexually dimorphic facial width-to-height ratio in an analysis of a series of human skulls representing different stages of ontogeny. They found that the sex difference emerged around puberty, which is when sex differences in facial structure related to body size appear, in part due to increased testosterone concentrations at puberty in boys (Verdonck et al. 1999). This finding is consistent with a recent study demonstrating a positive correlation between salivary testosterone concentrations and ratings of facial masculinity (Penton-Voak & Chen 2004). The sex difference in the facial ratio observed in skulls was independent of body size and of other size-related facial variation, and thus suggests that this sexual dimorphism may reflect a selection pressure that is independent of body size (Weston et al. 2007). A similar sexual dimorphism in the face, which was independent of body size, was also reported in chimpanzees (Weston et al. 2004).

The data obtained here suggest that for men variation in the width-to-height ratio from neutral faces may be an honest signal of propensity for aggressive behaviour. Clearly, an angry facial expression is a direct way to communicate one's emotional state and behavioural intent. However, it remains possible that subtle cues from a neutral face may have been selected because they provide information as to an individual's behavioural dispositions. Notably, angry facial expressions consist of lowering the brow and raising the upper lip, a pattern of muscle activity that increases the facial width-to-height ratio. From an evolutionary perspective, these findings suggest that selection pressures may have shaped the perceptual system to be especially attuned to cues of threat and/or aggression. However, it will be important to examine the extent to which people are sensitive to individual differences in facial width-to-height ratio and whether this facial metric is used to guide behaviour. Another possibility is that the relationship observed between the facial metric and aggressive behaviour was partly influenced by the posture of the head in the photographs (e.g. more aggressive men may tilt their head upwards and thereby foreshorten the vertical measurement of the face). It is also possible that stronger relationships would have been observed between the facial ratio and aggressive behaviour if direct measurements of the face were made instead of using photographs and had we been able to control facial expression in the faces of the hockey players.

There was no relationship between trait dominance and aggressive behaviour in our sample, although individual differences in trait dominance were associated with self-report measures of trait aggression in both men and women in other studies (Archer & Webb 2006 Johnson et al. 2007). This disparity may reflect that the PSAP is a behavioural measure designed to assess situation-specific reactive aggression, whereas the other studies measured a broader range of aggression (physical, verbal, hostile and anger) across several situations using self-report. However, the higher trait dominance in men than in women found here is consistent with previous studies using similar self-report measures (Budaev 1999 Costa et al. 2001). Furthermore, the sex difference in aggressive behaviour on the PSAP is consistent with that reported in the literature (reviewed in Archer 2004). The fact that there were no sex differences in reward or protection responding on the PSAP suggests that men were equally motivated to earn reward and avoid punishment (i.e. point subtractions).

There is much research literature addressing the role of the face in social interactions, and there is some literature indicating that faces can be used to gauge certain personality traits above chance (e.g. Penton-Voak et al. 2006). Such judgements are made in less than 40 ms, made with high consistency and have some predictive values (Bar et al. 2006 Willis & Todorov 2006 Ballew & Todorov 2007). For example, women's judgements of the extent to which a man was interested in infants based on his face predicted his actual interest in infants (Roney et al. 2006). Judgements of competence, intelligence and leadership based on only the facial appearance of political candidates (and independent of age and attractiveness) predicted the outcome of the elections (Todorov et al. 2005). Judgements of dominance predicted career success (Mueller & Mazur 1996) and age at first copulation (Mazur et al. 1994). Another study reported that participants' judgements of the personality traits of power (competence, dominance and facial maturity) and warmth (likeability and trustworthiness) in the faces of CEOs of Fortune 500 companies predicted the profits of the CEO's company (Rule & Ambady 2008). However, whether the actual success of the individuals whose faces were judged is partly due to shared societal stereotypes (e.g. the success of attractive people is in part because they are judged as more intelligent Zebrowitz et al. 2002) continues to be debated.

The novel finding of the present study is that individual differences in facial characteristics predict behaviour: Variability in a sexually dimorphic facial metric in men, which is independent of body size, predicted aggressive behaviour in a laboratory setting and in male hockey players. The relationship between within-sex variation in facial width-to-height and aggressive behaviour might reflect a common relationship to a third variable, such as organizational effects of testosterone as part of sexual differentiation in adolescence, which influences both the development of the physique and the nervous system (reviewed in Sisk & Zehr 2005 McCormick & Mathews 2007). The relationship between facial morphology and aggressive behaviour suggests that this characteristic may be an honest signal, perhaps comparable to honest signals in other species that predict factors such as phenotypic quality (Vanpe et al. 2007) or aggressive intent (Morestz & Morris 2006 Laidre & Vehrencamp 2008).

All procedures of the study were approved by the university's ethical review committee.


RELATED ARTICLES

Those high in self-centred impulsivity also tend to neglect the social norms and regulations that the rest of us live by.

MEN WITH WIDE FACES EARN £1,300 MORE THAN COLLEAGUES

Researchers in the US claim people with wide faces are more likely to get a bonus compared with their thin-faced rivals

Fuller faced workers earn £1,300 (£2,090) more than those with narrow faces when asking for a bonus, the study found.

However, researchers said this comes with a compromise. Wide faced people fared less well when it came to business negotiations.

And men who are more attractive are better collaborators compared to less attractive men, they said.

Previous research based on the 'facial width-to-height ratio' found individuals behave more selfishly when interacting with men with wider faces.

It claimed that while men with wider faces are more likely to lie and cheat, they tend to lead more financially successful firms.

Fearless dominance, meanwhile, includes a tendency to embrace risk without any fear, showing limited reaction to awful events that would make the rest of us panic - combined with a tendency to appear charming and influential.

Although this study finds a correlation, the researchers stress that it doesn't mean all men with wide faces have psychopathic tendencies.

The facial width to height ratio (fWHR) is worked out by measuring the horizontal distance between the outer edges of the cheekbones and the vertical distance from the highest point of the top lip to the highest point of the eyelids.

The width is then divided by the height.

For the study, the researchers asked 96 adult male university students and 41 male prisoners at a young offenders institution to complete a standard questionnaire that psychologists use to measure psychopathic traits.

Known as the Psychopathic Personality Inventory-Revised (PPI-R) test, it creates a total psychopathy score (PPI-R total) and studies fearless dominance, self-centered impulsivity, and coldheartedness.

Following the questionnaire, the men were asked to sit with their faces on a chin-rest, while their photographs were taken.

The researchers measured the men's fWHRs from these photos and correlated the results with their questionnaire answers.

The facial width to height ratio (fWHR) is worked out by measuring the horizontal distance between the outer edges of the cheekbones and the vertical distance from the highest point of the top lip to the highest point of the eyelids. The width is then divided by the height. Shia La Boeuf and Wayne Rooney both have high fWHR

Face width in men is affected by testosterone exposure during puberty, with wider faces reflecting higher levels of testosterone, the researchers from the Johann Wolfgang Goethe University in Frankfurt said.

'Without doubt, testosterone has long-lasting effects on the brain, particularly during sensitive developmental periods such as puberty,' they wrote in the journal Personality and Individual Differences.

'The affected brain regions include the amygdala and the hippocampus, limbic structures that are crucially involved in socio-emotional behaviour.

'Notably, these two regions are among the core regions for which structural and functional brain abnormalities have been reported in psychopathy.'

Previous research found that both men and women with wide faces tend to be more aggressive, dominant and angry, according to British research. Those with broad features - Sylvester Stallone (left) or Sarah Palin (right) - are more likely to have bad tempers and display bouts of verbal or physical aggression

Previous studies have found that women are more likely to want a man with a wide face for a fling, but less likely to see him as husband material, while wide-faced footballers score more goals but commit more fouls.

Last year, a separate study found both men and women with wide faces tend to be more aggressive, dominant and angry.

Those with broad features - such as Wayne Rooney, Sylvester Stallone or Sarah Palin - are more likely to have bad tempers and display bouts of verbal or physical aggression.

Psychologists think the trait is linked to the evolutionary benefit of having thick cheekbones.

Those who had more robust facial bones could be more aggressive, because they could better withstand a punch, the scientists suggest.


Materials and Method

Participants and Design

A total of 1,337 Chinese Executive MBA students (Mage = 40.67, SDage = 4.74) were randomly assigned to 288 teams of four or five people and participated in an intergroup negotiation between buyers and sellers as part of a class exercise. Sample size was determined by the class size. Each team was also assigned a team role of buyers or sellers. The data were collected across two semesters in a major Chinese business school at its Beijing (Northern China), Shanghai (Eastern China), and Shenzhen (Southern China) campuses. The second wave of participants (n = 697) used a negotiation exercise slightly revised from the one used by the first wave of participants (n = 640). The payoff schedules in the two exercises were the same (see Table 1) and we controlled for exercise throughout our data analysis. The independent variables were the team’s average FWHR and maximum individual FWHR, as the two variables are central for testing the role that the FWHR might play in intergroup negotiations. The dependent variables were the number of points earned in the negotiation (M = 6,572.12, SD = 1,060.40, converted to z-scores independently for each wave in our analyses).

TABLE 1. Payoff schedule in negotiation.

Materials and Procedure

Teams were given 35 min to prepare for the negotiation in their own teams and 45 min to complete the negotiation with their counterparts. The negotiation exercise involved negotiating the terms of an engineering project contract between a buyer and a seller. During the preparation time, teams were provided with a description of the negotiation and a payoff matrix outlining the points awarded for each issue (see Table 1). Teams engaged in a mixed-motive negotiation with one distributive issue, two integrative issues, and one compatible issue, where both parties had identical interests. Distributive issues are zero sum as both parties have opposing interests. Integrative issues provide the opportunity to create value by trading off on issues. The study was conducted in compliance with APA ethical standards and was approved by the Human Research Ethics Committee of ShanghaiTech University as part of a larger research project examining background information of the students and negotiation outcomes produced in class exercises. Because the study was part of a class exercise, the ethics committee provided exemption from obtaining informed consent.

FWHR Measurement and Data Exclusion

As part of the process of enrolling in the Executive MBA program, participants were photographed front-on and posed with a neutral expression. To calculate FWHR, the bizygomatic width of the face is divided by height of the face (see Figure 1). The bizygomatic width refers to the distance between the left and right zygon. The height of the face is measured from the highest point of the upper lip to the highest point of the eyelids (Carré and McCormick, 2008). An image-processing program was used to rotate the photographs so that the pupils were on the same transverse plane and the height and width was measured (Kramer et al., 2012). To calculate FWHR all facial boundaries need to be clearly visible. Following previous research, any participants with a tilted head, hair covering their face, visible teeth or asymmetry in their eyes or mouth were excluded from the data analyses (n = 150 males). We also excluded 44 very overweight individuals as their zygons could not be clearly identified. As a large number of the sample wore glasses (44%), data from participants with glasses were retained in the analyses (Carré et al., 2010). We did not deem glasses as problematic because the facial boundaries remained visible. Of all of the participants, ten did not provide their photographs. Female negotiators (n = 326) were excluded from the analyses because FWHR is a more reliable marker amongst men than women (e.g., (Carré and McCormick, 2008) Geniole et al., 2015). Following these exclusions, any teams with less than two participants were excluded from the analyses along with the opponent team (n = 101). Of the remaining 236 teams, ten were excluded because they reached impasses in the negotiation (n = 26). This left a total of 680 male negotiators in 226 teams. Two research assistants independently measured all the remaining photographs. Inter-rater agreements were high (α = 0.99 for facial width, α = 0.99 for height, and α = 0.99 for overall FWHR). We therefore averaged measurement of the two assistants for all FWHRs. Mean FWHR of the teams was 2.18 (SD = 0.08) and ranged from 1.99 to 2.50. Finally, we examined the photographs of all 326 women’s faces but only 123 (38%) could be measured for the FWHR because of head tilt, hair covering their face, or visible teeth or asymmetry of the eyes or mouth. Thus, we could not appropriately conduct analyses with women. However, including gender composition as a covariate showed that the number of women did not have systematic impact on our dependent variables.

FIGURE 1. Example of measuring FWHR. Vertical lines represent the distance between the left and the right zygion (bizygomatic width). Horizontal lines represent the distance between the highest point of the upper lip and the highest point of the eyelids (facial height). This photo is for illustrative purpose only and does not depict an actual participant in the study. To protect the identity of participants, we produced the present photo by merging three photos using Psychomorph (Tiddeman et al., 2005).


The Facial Width-to-Height Ratio Predicts Sex Drive, Sociosexuality, and Intended Infidelity

Previous research has linked the facial width-to-height ratio (FWHR) to a host of psychological and behavioral characteristics, primarily in men. In two studies, we examined novel links between FWHR and sex drive. In Study 1, a sample of 145 undergraduate students revealed that FWHR positively predicted sex drive. There were no significant FWHR × sex interactions, suggesting that FWHR is linked to sexuality among both men and women. Study 2 replicated and extended these findings in a sample of 314 students collected from a different Canadian city, which again demonstrated links between the FWHR and sex drive (also in both men and women), as well as sociosexuality and intended infidelity (men only). Internal meta-analytic results confirm the link between FWHR and sex drive among both men and women. These results suggest that FWHR may be an important morphological index of human sexuality.

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Why does it matter?

At this point, you’re probably thinking, “Well that’s some lovely nit-picking nerdery there, Derek – but why does it matter?”. That’s a good question. And there’s a good answer.

The reason it’s important to understand the levels of measurement in your data – nominal, ordinal, interval and ratio – is because they directly impact which statistical techniques you can use in your analysis. Each statistical test only works with certain types of data. Some techniques work with categorical data (i.e. nominal or ordinal data), while others work with numerical data (i.e. interval or ratio data) – and some work with a mix. While statistical software like SPSS or R might “let” you run the test with the wrong type of data, your results will be flawed at best, and meaningless at worst.

The takeaway – make sure you understand the differences between the various levels of measurement before you decide on your statistical analysis techniques. Even better, think about what type of data you want to collect at the survey design stage (and design your survey accordingly) so that you can run the most sophisticated statistical analyses once you’ve got your data.


The Golden Ratio

So, the more a body fits into the parameters laid out by the golden ratio, the more attractive it will be, both physiologically and psychologically. It's a really interesting bit of science and evolutionary psychology, and it begs the question: How do we use this information to help you achieve your fitness goals and get the body that you want?

Well, the first thing is to realize that, chances are, the body you are working so hard for is based on our intrinsic ideas of symmetry. Of course, the numbers are just everywhere in places we can't control. Thankfully, not many women are going to be looking closely enough at your feet and shins to make sure they add up correctly.

That said, the golden ratio also applies heavily in places we can control, and the most important one by far is the most visible: your waist-to-shoulder measurement. As mentioned earlier, broad shoulders imply strength, power and virility, and are, therefore, a mating qualifier that makes a body appear more attractive to the opposite sex. But &ldquobroad&rdquo is a relative term. Something can only be &ldquobroad&rdquo if it&rsquos compared to something less so, which is where your shoulder-to-waist measurement (and the golden ratio) come in.

The Adonis Index: How Do You Measure Up

Now, let&rsquos say you&rsquore a skinny guy looking to gain some muscle. If your waist measures 28 inches, then your goal for your shoulders should be just about 45.3 inches. Even if you don&rsquot immediately gain a tremendous amount of muscle, as long as you develop your shoulders to fit that proportion, you&rsquore on your way to a &ldquoperfect&rdquo body.

Alternatively, let&rsquos say you&rsquore on the bigger side and you want to drop some weight. Maybe your shoulders measure 54 inches around &mdash quite a big guy, and certainly powerful looking &mdash but your waist could use some help. In this case, all you need to do is drop enough weight to bring your waist measurement down to around 33.5, and your proportions will be immediately more attractive. That means, you don&rsquot need to get &ldquosuper lean&rdquo just to improve your body and improve your Adonis Index.

A Case Study

If he diets down a bit and brings his waist measurement down to 32, his measurement will jump to 1.406. That means without increasing his muscle mass at all, a mere two-inch reduction in his waist has brought him a lot closer to an ideal Adonis Index and an improved body.

If this client wants to take it a step further, he can adjust his training workout to add size to his shoulders. If he can add three inches on the total circumference, he&rsquos pretty much set. At 48 inches with a 32 waist, our client is now at an Index 1.5, which is amazingly close.

Put It In Action

If you're trying to build an impressive body &mdash with strong, broad shoulders and a narrow waist &mdash you definitely want to pay careful attention to the golden ratio and to your Adonis Index. The perfect body may be closer than you think.

Next Steps:
1- Determine your goal: fat loss or muscle building?
2- If it's fat loss, measure your shoulders. If muscle building, measure your waist.
3- If you&rsquore trying to lose fat, focus on getting your waist measurement to fit the Adonis Index, as determined by your shoulder measurement. If you&rsquore trying to gain muscle, focus on developing your shoulders to be 1.618 times your waist measurement.

Let us know how far away from your goal you are in the comments field below.


Is there a script to measure face width to height ratio? - Psychology

Do you remember being in high school or college and noticing a group of females who had their own exclusive group? More than likely they were the "popular" girls, the most pretty and conceited. When these pretty girls are depicted in movies they often get their egos crushed by less attractive classmates with better personalities. Unfortunately, in real life this is unlikely. Being "beautiful" has its rewards and these usually continue throughout adulthood.

Studies show attractive people prefer to associate with others like themselves.

The secret of beauty and attractiveness has been a quest of humans for as long as we have been civilized. Many women (and some "metrosexual" men) spend up to one-third of their income trying to look good. And contrary to what you might think, the reasons for this obsession with beauty go way beyond sexual attraction.

Besides being popular, beautiful people get special attention from teachers, the legal system and especially potential employers [5]. Good-looking people tend to make more money than their plain-Jane counterparts. A study by the Federal Reserve Bank of St. Louis found that beautiful people tend to earn 5 percent more an hour than their less comely colleagues. If that weren't enough, the Fed also discovered a "plainness penalty", punishing below-average-looks with earnings of 9 percent less an hour [6].

Isn't beauty in the eye of the beholder?

While we instinctively know what appeals to our own sense of beauty -- we know it when we see it -- defining what determines attractiveness is not always easy. In frustration, we often give up and claim that "beauty is in they eye of the beholder." But is beauty really a personal, subjective phenomenon?

Recent studies have shown that the secret of beauty may at last be understood. It seems that attractiveness may be hard wired in our brains.

Experiments designed to measure attractiveness usually involve showing a series of images of human faces and asking subjects to rate their visual appeal. Surprisingly, people from a variety of different ages, races and cultures agree on what is and isn't beautiful.

Babies as young as 3 months can identify and prefer faces that most adults would deem beautiful. Europeans can pick out the same beautiful Japanese faces as Japanese subjects Japanese can agree on which European faces another Europeans will view as beautiful. In fact, humans can even agree on the attractiveness of monkey faces [7], thus ruling out most unique racial, cultural and even species influences. So what's going on?

Facial recognition is a complex process. Only recently, with the need to spot criminals and terrorists, computer facial recognition programs have been developed to analyze the subtle variations of such things as the space between our eyes, the size of our noses and the proportions of our facial features. Scientists have discovered certain mathematical facial proportions that identify beautiful people. But there is more to beauty than the mere arrangement of eyes, noses and chins.

Our brains do much more than simply recognize a beautiful face. Most people can assess emotions, personality traits and fertility -- as well as beauty -- almost instantaneously. In fact, the human brain has special part called the fusiform, located in the back of the head, near the spine. It's the same neural pathway needed to recognize faces of family, friends and people we have met.

When it's damaged, the patients cannot recognize anyone, even people they have just met. But especially interesting was the fact the patient with a damaged fusiform cannot discriminate between photographs of plain and beautiful faces!

Studies show that when we recognize a face as "beautiful" we are actually making a judgement about the health and vitality of that individual. We interpret facial symmetry (the similarity of left and right halves of a face) and the smoothness of the skin to mean that a person has good genes and has been free from diseases. This is part of what we mean by "beautiful", but it is just the beginning.

Scientists say that facial symmetry is one of the best observational indicators of good genes and healthy development and that these traits are what we mean when we say someone is attractive. Look at these examples below.

Which face do you think looks more healthy?

A non-symmetrical face, or Facial Asymmetry (FA), increases with the presence of genetic disturbances such as deleterious recessives and with homozygosity*. Also, FA increases with the exposure to environmental perturbations during development (i.e. extremes in temperature and pollution). Think of Facial Asymmetry as the inability of an individual to resist the disruptions in developmental symmetry. This implies a genetic weakness and less than optimum health.

Bilateral Symmetry (see image above) is thus equated with heterozygosity* and resistance to infection and debilitating pathogens. Bilateral Symmetry and parasite resistance are factors that show optimum health and increase the success in intersexual and intrasexual competition [8].

*Note: The term homozygosity refers to the similarity of genetic characteristics that can cause a weakening of a species -- such as occurrs with in-breeding. Heterozygosity, on the other hand, is the result of genetic variety which is able to change and adapt to environmental conditions. The latter is believed to be more beneficial to a species.

Facial Attraction: Choice Of Sexual Partners Shaped The Human Face

Researchers at the Natural History Museum [9] have discovered that men with large jaws, flaring cheeks and large eyebrows are "sexy" -- at least in the eyes of our ancestors. Facial attractiveness played a major role in shaping human evolution. As studies on our fossil ancestors have shown, our choice of sexual partners has shaped the human face to what it is today.

"I'm too sexy for my face. "

Ancient fossils reveal how the human face went through an evolution to reach its present appearance. Throughout history, humans have been making judgements about desirable facial characteristics and mating more often with the opposite sex who had them. Eventually everyone had them.

According to palaeontologists at the Natural History Museum, men have evolved short faces between the brow and upper lip, which exaggerates the size of their jaw, the flare of their cheeks and their eyebrows. The shorter and broader male face has also evolved along with shrunken canine teeth. This makes men look less threatening to competitors, yet attractive to mates.

At puberty, the region between the mouth and eyebrows, known as upper facial height or UFH, develops differently in men and women. Unlike other facial features, this difference cannot be explained simply in terms of men being bigger than women.

Aggressive Personality Shows On Your Face

According to a 2007 study [1], angry words and gestures are not the only way to get a sense of how temperamental a person is. According to the srudy published in Psychological Science, a quick glance at someone's facial structure is enough for us to predict their tendency towards aggression.

Facial width-to-height ratio (WHR) is determined by measuring the distance between the right and left cheeks and the distance from the upper lip to the mid-brow. A high WHR means the width of the face is greater that the height -- in other words, a wide face.

During childhood, boys and girls have similar facial structures, but during puberty, males develop a greater WHR than females. Research suggests that males with a larger WHR act more aggressively than those with a smaller WHR.

A good example of this can be seen in the aggressive sport of hockey. Studies have shown that hockey players with greater WHR earn more penalty minutes for fighting and aggression per game than players with lower WHR.

Chances are it's wider than yours, according to a new Brock University study that equates the width of a hockey player's face with his or her aggressive tendencies [14].

"Playing hockey . you can almost tell just by looking at them that this person might be more aggressive than another person," says Justin Carré, a graduate student and the lead study author. The study appears in the journal Proceedings of the Royal Society: Biology.

In another experiment, psychologists Justin M. Carré, Cheryl M. McCormick, and Catherine J. Mondloch of Brock University wanted to see if it is possible to predict another person's propensity for aggressive behavior simply by looking at their photograph.

In the study, participants were shown pairs of photographs or 'averaged' facial images of men and women in their early 20s with two opposing attitudes to relationships. The participants were asked to choose the face that they felt would be more open to short-term sexual relationships, one-night stands and the idea of sex without love. They were also asked which face they thought was the most attractive for a long- or short-term relationship, who was more masculine or feminine, and who they thought was generally attractive.

Volunteers viewed photographs of faces of men for whom aggressive behavior was previously assessed in the lab by calculating their WHR. The volunteers had no idea how the photographed subjects rated on the aggression scale. After viewing the photographs, the volunteer subjects rated how aggressive they thought each person was on a scale of one to seven. They were allowed to view the photographs of each face for either 2000 milliseconds or 39 milliseconds.

The photographs were very revealing. The Volunteer subjects estimates of how aggressive the photographed person was agreed with the results of the prior assessment. This was true even if they saw the picture for only 39 milliseconds.

Apparently the brain can decide whether a person is aggressive almost instantly!

Also interesting was the fact that the volunteer subjects estimated a higher aggression assessment to photographed faces with higher WHR ratios -- the greater the WHR, the higher the aggressive rating, reinforcing that we may use this aspect of facial structure to judge potential aggression in others.

These findings indicate that subtle differences in face shape may affect personality judgments, which may, in turn, guide how we respond to certain individuals. And it all happens behind the scenes, unconsciously, in an instant.

Many recent experiments have shown that, aside from symmetry, WHR ratios and being "healthy", men and women form opinions about attractiveness based on slightly different criteria which can change depending on such things as their age, hormones and potential for being a mate.

Attractiveness From a Female's Perspective

In one experiment [3], the researcher selected photographs of a man with what has been described as "feminine" features. These included a small nose, narrow chin and large eyes. This image was digitally morphed with an image of a very "masculine" face, with a strong jaw, big nose and small eyes.

The two images were morphed in progressive steps in such a way that the viewer could adjust the degree of either masculine or feminine features with a slider, corresponding to which image the female subjects thought was most attractive. Subjects were also asked about their menstrual cycles to determine their potential fertility and estrogen levels.

While most women preferred the middle range -- a combination of both feminine and masculine features -- subjects who were in their most fertile hormonal cycles preferred the more masculine image. The same women, when later tested during their infertile days, selected the more average looking male image as most attractive.

Scientists reason that fertility causes hormonal changes in the brain that seek out strong testosterone traits in their potential mates. These traits are usually associated with aggressive behavior, risk taking and verility -- traits that are advantageous in the act of procreation.

Some other interesting studies may be explained using this biological model.

University of Aberdeen psychologist Ben Jones and his team tested the impact that the opinions of others has on our perception of beauty by giving women a test in which they had to choose the more attractive of pairs of male faces and to rate how much more handsome they found them. [15]

They were then shown a short video in which the same faces were displayed. But each face was being looked at by a woman smiling or one showing a bored or neutral expression.

After watching the video, the researchers repeated the initial test.

This shows that people are using the attitudes of others to shape their own judgement about the attractiveness of some people.

In other words, a woman may not be sure how attractive a face is. But if other women show that they're attracted they dismiss their doubt. This may explain the "groupie" and the "cult of personality" phenomenon and why so many ugly men learn to play the guitar.

The test had the opposite effect on men. When they were asked to look at the same male faces, those who got the approving female glances were rated less attractive. Could this be jealosy?

When women are assessing a man's face for a marriage partner they usually react to a man with a wide smile, small eyes, a big nose and a large jaw. This is thought to indicate a strong testosterone level, a potentially good provider and protector for family life.

Studies show that younger women rely more on the physical attractiveness of a man than do older women. The latter incorporate such things as wealth, stability, power and faithfulness in their definition of attractive. This demonstrates wisdom since the most recent studies prove that less attractive men are more faithful and loving than handsome men.

Attractiveness From A Male's Perspective

As might be expected, females tend to place less of their criteria for beauty on physical attractiveness than do males. This might be a lucky break for unattractive men! A recent study published in Psychological Science found that when seeking a date, men do not factor in their own attractiveness (or lack of) when assessing their chances of success with a beautiful woman. Sometimes they are lucky, but the study found that, most of the time, people with similar levels of physical attractiveness usually end up dating each other and they aspire to date people who are slightly more attractive than themselves.

When reality sets in, less attractive people justify their less than beautiful partners by emphasizing their personality traits, like a sense of humor or kindness.

The ideal face of an attractive woman, according to experiments with men, has high cheek bones, big eyes and a thin jaw. From infancy to adulthood, our faces are growing at different rates and proportions, depending on such things as hormones. When viewing the proportions of elements such as nose size and facial proportions, males usually select features that are characteristic of a woman of 24.8 years -- perhaps also related to the perceived age of optimal fertility.

Some men prefer even younger proportions because these child-like faces stimulate emotions of caring and protection. These emotions seem to be more significant than sexual urges and procreation in some men. This can be in the psychological realm that dangerously approaches pathology and the law. Yet this "lolita" proclivity seems similarly hard wired [see viewzone article on pedophilia].

Professor Victor Johnstone, of the University of New Mexico studied this "lolita" phenomenon and reported that it was quite prevalent among all men:

"We found that that there definitely was a type of adult female face that men found attractive and that it was different from the average face. The two key measurements are the distance from the eyes to the chin, which is shorter -- in fact it is the length normally found in a girl aged eleven and a half and the size of the lips, which are fatter -- the size normally found on a fourteen-year-old girl".

[Above: Our changing concept of beauty. Venus of Willendorf (27,000 BCE), Boticelli's Primavera (1500s), Twiggy (1960s)]

The ideal body type has changed throughout history, reflecting the changing roles of women and men alike. Primitive cultures viewed a woman as the mother of a family and preferred a healthy, corpulent figure. Small breasts and a wide pelvis triumphed during the Renaissance. By the 1970s, women were being viewed as separate from their sexuality. "Thin (no breasts) was in."

So have things changed today?

When it comes to body proportions, most men usually report liking big breasts and hips -- again possibly linked to the ability to bare and nurture offspring. Estrogen, the hormone associated with female fertility, encourages fat deposits around the buttocks and thighs. So full buttocks and a narrow waist send out the same message as the ideal face: "I'm full of estrogen and very fertile."

Studies by Dr Devendra Singh published in the Royal Society Journal [12] show the optimal preferred waist to hip ratio was 0.67 to 0.80, while a larger waist was viewed by males as meaning the woman was more faithful and kind and a woman with a smaller waist was judged as being more aggressive and ambitious.

Dr Michael Cunningham of Elmhurst College [13], Illinois, found that if a male is judging a female in an interview for a job, a woman with expressive eyebrows and dialated pupils has the edge and is likely to be considered more competent. The same features would not be judged as attractive if the same man was looking for a mate. Cunningham also found that attractive women with mature features, such as small eyes and a large nose, received more respect from men.

"Average" is beautiful -- not!

In the late 1870s, scientist and eugenicist Sir Francis Galton developed an image of the prototypical "face of crime" by creating composite photos of men convicted of serious offenses. Though Galton failed to discover anything abnormal in his composite criminal faces, he did find that the resulting visages were shockingly handsome. Later, Galton tried to make the case that a face with average proportions would always look more beautiful than a unique, individual face.

Subsequent studies of both men and women had shown that averaging features seemed to make the faces more attractive than any specific face. When a collection of computer averaged faces and real female faces were submitted to a famous modeling agency for comments, 80% of the computer generated faces were selected as having potential to be a model.

Scientists believed that average faces were more easy for the brain to recognize and require less analysis and processing in the fusiform. This ease of recognition was perceived as attractiveness.

But this theory has recently been opposed by Dr David Perrett, of the University of St Andrews, who found that individual faces were judged more attractive than the composites.

This would account for the popularity of actresses such as Brigitte Nielsen and Daryl Hannah [right], who have features that are far from average.

Like Mother. Like Wife?

Psychologist David Perrett [16] found that young men and women prefer faces that most resemble their mothers and fathers. Members of a close family also often share the interpretation of certain facial characteristics in judging someone's personality. Although this does not relate directly with beauty or attractiveness, it demonstrates that some aspects of evaluating facial characteristics may be learned.

My own take on this is that it's a matter of nature and nurture. Various centers of our hard wired brain, like the fusiform, compete to control our daily decisions. One center is concerned with mate selection based on physical traits while other brain regions which have had social experience respond to a potential mate who is also intelligent, honest, faithful, kind and sane.

Attractiveness, in the end, actually is unique to each individual. It encompasses instincts of survival which are tempered by social experiences and the need for certain qualities, like kindness, intelligence and compatibility. But scientists have also shown that we may be attracted to less permanent characteristics, like the willingness to have casual sex. And apparently we can sense that in a person's face also.

Suitors can tell a young person's attitude to sexual relationships by the look on their face, according to new research [4] which gives deeper insight into mate attractiveness.

The Durham University-led study of 700 heterosexual participants also found that young men and women look for completely opposite traits when it comes to relationships with the other sex.

Men generally prefer women who they perceive are open to short-term sexual relationships while women are usually interested in men who appear to have potential to be long-term relationship material.

Scientists say the research shows people can use their perceptions to make more informed partner selection depending on the type of relationship they are pursuing. The study is a significant step in further understanding the evolution of partner choice.

Participants were asked to judge the attractiveness and attitudes to sex of the opposite sex from their facial photographs. These perceptual judgements were then compared with the actual attitudes and behaviours of the individuals in the photographs, which had been determined through a detailed questionnaire. The people in the photographs were all in their early 20s.

The experiments found that the men and women taking part could generally judge from photographs who would be more interested in a short-term sexual relationship. In the first study sample of 153 participants, 72 per cent of people correctly identified the attitudes from photographs more than half of the time. However, further questioning showed that the participants were not always confident in their judgements.

The composite image on the right is more likely to be interested in a short-term sexual relationship. (Credit: Image courtesy of Durham University)

The research, published in Evolution and Human Behavior [17], also found that women who were open to short-term sexual relationships were usually seen by others as more attractive -- although researchers can not determine precisely why without further investigation.

The men who were most open to casual sex were generally perceived as being more masculine-looking, with facial features including squarer jaws, larger nose and smaller eyes. These findings support previous research carried out by the Durham team which found that women see masculine men as more likely to be unfaithful and as worse parents.

Lead author Dr Lynda Boothroyd from Durham University's Psychology Department said: "Our results suggest that although some people can judge the sexual strategy of others simply from looking at their face, people are not always sure about their judgements possibly because the cues are very subtle. Yet preferences for different types of face were actually quite strong.

"This shows that these initial impressions may be part of how we assess potential mates -- or potential rivals -- when we first meet them. These will then give way over time to more in depth knowledge of that person, as you get to know them better, and may change with age".

Lots of previous studies have shown that people can judge a lot about a person from their face, including things like health and even some personality traits like introversion, but this really is the first study to show that people are also sensitive to subtle facial signals about the type of romantic relationships that others might enjoy." -- Dr Ben Jones, from the University of Aberdeen's Face Research Lab

Professor David Perrett from the University of St Andrews cautioned:

  • Attractive people earn more salary and get more promotions than average looking people.
  • One main feature that is indicative of healthy genetics is the symmetry of the face.
  • Recognition of beauty fosters better mate selection and healthier breeding.
  • Beautiful people usually associate with other beautiful people.
  • Beautiful people prefer date people who are a little more attractive than themselves.
  • Beautiful people and less beautiful people judge beauty in the same way, although less beautiful people often consider other factors as equally important.
  • People consider facial characteristics similar to their parents to be more attractive.
  • Members of a family or relations judge facial characteristics as implying personality traits in the same way.
  • Studies find couples often resemble eachother in facial characteristics.
  • Attractive people are viewed as honest and helpful while unattractive people are viewed as rude and unfair.
  • Women find a man more attractive in experiments when other women are pictured smiling at him.
  • Females find extremely masculine faces more attractive during their fertile periods.
  • Studies find less attractive men are more faithful and loving than handsome men.
  • Women looking for a mate like small eyes, a big nose and a large jaw.
  • Males in experiments prefer facial ratios similar to a woman of 24.8 years old.
  • The ideal figure of a woman is a waist to hip ratio of 0.67 to 0.80

Interpersonal attractiveness is just one of the many facets of what we call beauty. Its connection to sex, mating and procreation are obvious. So too is the fact that much of our appreciation of beauty appears hard-wired in our brains. But what about other kinds of beauty?

We can all appreciate a beautiful scene or view, the beauty of a flower or a particular combination of colors or shapes. Are these also hard-wired?

We'll explore some examples of beauty and explore how we can tell the good art from the bad. We'll ask the question: "If appreciation of art is hard-wired, what evolutionary significance does it imply?"

[1] Weston EM, Friday AE, Lio P (2007) Biometric Evidence that Sexual Selection Has Shaped the Hominin Face. PLoS One 2(8): e710. doi:10.1371/journal.pone.0000710

[2] Rupp et al. Partner Status Influences Women's Interest in the Opposite Sex. Human Nature, 2009 20 (1): 93 DOI: 10.1007/s12110-009-9056-6

[3] Steven W. Gangestad, Randy Thornhill, Christine E. Garver-Apgar. Men's facial masculinity predicts changes in their female partners' sexual interests across the ovulatory cycle, whereas men's intelligence does not. Evolution and Human Behavior, 2010 31 (6): 412 DOI: 10.1016/j.evolhumbehav.2010.06.001

[4] Durham University (2008, April 9). Attitudes Towards Sexual Relationships Can Be Judged From Photos Of Your Face. ScienceDaily. Retrieved May 4, 2011, from http://www.sciencedaily.com­ /releases/2008/04/080408202048.htm

[5] Relative importance of applicant sex, attractiveness, and scholastic standing in evaluation of job applicant resumes. Dipboye, Robert L. Fromkin, Howard L. Wiback, Kent Journal of Applied Psychology, Vol 60(1), Feb 1975, 39-43. doi: 10.1037/h0076352

[7] Leopold, D.A. & Bondar, I. (2005). Adaptation to complex visual patterns in humans and monkeys. )pp. 189-211), Oxford University Press Leopold, D.A. & Bondar, I. & Giese, M.A. (2006) Norm-based face encoding by single neurons in the monkey inferotemporal cortex, Nature, 442, 572-575.

Dahl et al. The Thatcher illusion in humans and monkeys. Proceedings of The Royal Society B Biological Sciences, 2010 DOI: 10.1098/rspb.2010.0438

[8] Zaidel, D. Aarde, S. Baig, K. (2005). "Appearance of symmetry, beauty, and health in human faces". Brain and Cognition 57 (3): 261. doi:10.1016/j.bandc.2004.08.056. PMID 15780460.

[9] Weston EM, Friday AE, Lio P (2007) Biometric Evidence that Sexual Selection Has Shaped the Hominin Face. PLoS One 2(8): e710. doi:10.1371/journal.pone.0000710

[12] Dr Devendra Singh, from the University of Texas, in a study published in a Royal Society Journal.

[13] Michael R Cunningham, Journal of Personality and Social Psychology (1986) Volume: 50, Issue: 5

[14] Carré J M, Morrissey M D, Mondloch C J, McCormick C M, 2010, "Estimating aggression from emotionally neutral faces: Which facial cues are diagnostic?" Perception 39(3) 356 – 377

[15] Little, AC., Saxton, TK., Roberts, SC., Jones, BC., DeBruine, L., Vukovic, J., Perrett, DI., Feinberg, DR. & Chenore, T. (2010). 'Women's preferences for masculinity in male faces are highest during reproductive age-range and lower around puberty and post-menopause'. Psychoneuroendocrinology, 35 (6), pp. 912-920.

[16] David Perrett, In Your Face: The New Science of Human Attraction (Palgrave Macmillan, 2010)


Summary

In this blog post, we learned how to measure the size of objects in an image using Python and OpenCV.

Just like in our tutorial on measuring the distance from a camera to an object, we need to determine our “pixels per metric” ratio, which describes the number of pixels that can “fit” into a given number of inches, millimeters, meters, etc.

To compute this ratio, we need a reference object with two important properties:

  • Property #1: The reference object should have known dimensions (such as width or height) in terms of a measurable unit (inches, millimeters, etc.).
  • Property #2: The reference object should be easy to find, either in terms of location of the object or in its appearance.

Provided that both of these properties can be met, you can utilize your reference object to calibrate your pixels_per_metric variable, and from there, compute the size of other objects in an image.

In our next blog post, we’ll take this example a step further and learn how to compute the distance between objects in an image.

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Those high in self-centred impulsivity also tend to neglect the social norms and regulations that the rest of us live by.

MEN WITH WIDE FACES EARN £1,300 MORE THAN COLLEAGUES

Researchers in the US claim people with wide faces are more likely to get a bonus compared with their thin-faced rivals

Fuller faced workers earn £1,300 (£2,090) more than those with narrow faces when asking for a bonus, the study found.

However, researchers said this comes with a compromise. Wide faced people fared less well when it came to business negotiations.

And men who are more attractive are better collaborators compared to less attractive men, they said.

Previous research based on the 'facial width-to-height ratio' found individuals behave more selfishly when interacting with men with wider faces.

It claimed that while men with wider faces are more likely to lie and cheat, they tend to lead more financially successful firms.

Fearless dominance, meanwhile, includes a tendency to embrace risk without any fear, showing limited reaction to awful events that would make the rest of us panic - combined with a tendency to appear charming and influential.

Although this study finds a correlation, the researchers stress that it doesn't mean all men with wide faces have psychopathic tendencies.

The facial width to height ratio (fWHR) is worked out by measuring the horizontal distance between the outer edges of the cheekbones and the vertical distance from the highest point of the top lip to the highest point of the eyelids.

The width is then divided by the height.

For the study, the researchers asked 96 adult male university students and 41 male prisoners at a young offenders institution to complete a standard questionnaire that psychologists use to measure psychopathic traits.

Known as the Psychopathic Personality Inventory-Revised (PPI-R) test, it creates a total psychopathy score (PPI-R total) and studies fearless dominance, self-centered impulsivity, and coldheartedness.

Following the questionnaire, the men were asked to sit with their faces on a chin-rest, while their photographs were taken.

The researchers measured the men's fWHRs from these photos and correlated the results with their questionnaire answers.

The facial width to height ratio (fWHR) is worked out by measuring the horizontal distance between the outer edges of the cheekbones and the vertical distance from the highest point of the top lip to the highest point of the eyelids. The width is then divided by the height. Shia La Boeuf and Wayne Rooney both have high fWHR

Face width in men is affected by testosterone exposure during puberty, with wider faces reflecting higher levels of testosterone, the researchers from the Johann Wolfgang Goethe University in Frankfurt said.

'Without doubt, testosterone has long-lasting effects on the brain, particularly during sensitive developmental periods such as puberty,' they wrote in the journal Personality and Individual Differences.

'The affected brain regions include the amygdala and the hippocampus, limbic structures that are crucially involved in socio-emotional behaviour.

'Notably, these two regions are among the core regions for which structural and functional brain abnormalities have been reported in psychopathy.'

Previous research found that both men and women with wide faces tend to be more aggressive, dominant and angry, according to British research. Those with broad features - Sylvester Stallone (left) or Sarah Palin (right) - are more likely to have bad tempers and display bouts of verbal or physical aggression

Previous studies have found that women are more likely to want a man with a wide face for a fling, but less likely to see him as husband material, while wide-faced footballers score more goals but commit more fouls.

Last year, a separate study found both men and women with wide faces tend to be more aggressive, dominant and angry.

Those with broad features - such as Wayne Rooney, Sylvester Stallone or Sarah Palin - are more likely to have bad tempers and display bouts of verbal or physical aggression.

Psychologists think the trait is linked to the evolutionary benefit of having thick cheekbones.

Those who had more robust facial bones could be more aggressive, because they could better withstand a punch, the scientists suggest.


Materials and Method

Participants and Design

A total of 1,337 Chinese Executive MBA students (Mage = 40.67, SDage = 4.74) were randomly assigned to 288 teams of four or five people and participated in an intergroup negotiation between buyers and sellers as part of a class exercise. Sample size was determined by the class size. Each team was also assigned a team role of buyers or sellers. The data were collected across two semesters in a major Chinese business school at its Beijing (Northern China), Shanghai (Eastern China), and Shenzhen (Southern China) campuses. The second wave of participants (n = 697) used a negotiation exercise slightly revised from the one used by the first wave of participants (n = 640). The payoff schedules in the two exercises were the same (see Table 1) and we controlled for exercise throughout our data analysis. The independent variables were the team’s average FWHR and maximum individual FWHR, as the two variables are central for testing the role that the FWHR might play in intergroup negotiations. The dependent variables were the number of points earned in the negotiation (M = 6,572.12, SD = 1,060.40, converted to z-scores independently for each wave in our analyses).

TABLE 1. Payoff schedule in negotiation.

Materials and Procedure

Teams were given 35 min to prepare for the negotiation in their own teams and 45 min to complete the negotiation with their counterparts. The negotiation exercise involved negotiating the terms of an engineering project contract between a buyer and a seller. During the preparation time, teams were provided with a description of the negotiation and a payoff matrix outlining the points awarded for each issue (see Table 1). Teams engaged in a mixed-motive negotiation with one distributive issue, two integrative issues, and one compatible issue, where both parties had identical interests. Distributive issues are zero sum as both parties have opposing interests. Integrative issues provide the opportunity to create value by trading off on issues. The study was conducted in compliance with APA ethical standards and was approved by the Human Research Ethics Committee of ShanghaiTech University as part of a larger research project examining background information of the students and negotiation outcomes produced in class exercises. Because the study was part of a class exercise, the ethics committee provided exemption from obtaining informed consent.

FWHR Measurement and Data Exclusion

As part of the process of enrolling in the Executive MBA program, participants were photographed front-on and posed with a neutral expression. To calculate FWHR, the bizygomatic width of the face is divided by height of the face (see Figure 1). The bizygomatic width refers to the distance between the left and right zygon. The height of the face is measured from the highest point of the upper lip to the highest point of the eyelids (Carré and McCormick, 2008). An image-processing program was used to rotate the photographs so that the pupils were on the same transverse plane and the height and width was measured (Kramer et al., 2012). To calculate FWHR all facial boundaries need to be clearly visible. Following previous research, any participants with a tilted head, hair covering their face, visible teeth or asymmetry in their eyes or mouth were excluded from the data analyses (n = 150 males). We also excluded 44 very overweight individuals as their zygons could not be clearly identified. As a large number of the sample wore glasses (44%), data from participants with glasses were retained in the analyses (Carré et al., 2010). We did not deem glasses as problematic because the facial boundaries remained visible. Of all of the participants, ten did not provide their photographs. Female negotiators (n = 326) were excluded from the analyses because FWHR is a more reliable marker amongst men than women (e.g., (Carré and McCormick, 2008) Geniole et al., 2015). Following these exclusions, any teams with less than two participants were excluded from the analyses along with the opponent team (n = 101). Of the remaining 236 teams, ten were excluded because they reached impasses in the negotiation (n = 26). This left a total of 680 male negotiators in 226 teams. Two research assistants independently measured all the remaining photographs. Inter-rater agreements were high (α = 0.99 for facial width, α = 0.99 for height, and α = 0.99 for overall FWHR). We therefore averaged measurement of the two assistants for all FWHRs. Mean FWHR of the teams was 2.18 (SD = 0.08) and ranged from 1.99 to 2.50. Finally, we examined the photographs of all 326 women’s faces but only 123 (38%) could be measured for the FWHR because of head tilt, hair covering their face, or visible teeth or asymmetry of the eyes or mouth. Thus, we could not appropriately conduct analyses with women. However, including gender composition as a covariate showed that the number of women did not have systematic impact on our dependent variables.

FIGURE 1. Example of measuring FWHR. Vertical lines represent the distance between the left and the right zygion (bizygomatic width). Horizontal lines represent the distance between the highest point of the upper lip and the highest point of the eyelids (facial height). This photo is for illustrative purpose only and does not depict an actual participant in the study. To protect the identity of participants, we produced the present photo by merging three photos using Psychomorph (Tiddeman et al., 2005).


In your face: facial metrics predict aggressive behaviour in the laboratory and in varsity and professional hockey players

Facial characteristics are an important basis for judgements about gender, emotion, personality, motivational states and behavioural dispositions. Based on a recent finding of a sexual dimorphism in facial metrics that is independent of body size, we conducted three studies to examine the extent to which individual differences in the facial width-to-height ratio were associated with trait dominance (using a questionnaire) and aggression during a behavioural task and in a naturalistic setting (varsity and professional ice hockey). In study 1, men had a larger facial width-to-height ratio, higher scores of trait dominance, and were more reactively aggressive compared with women. Individual differences in the facial width-to-height ratio predicted reactive aggression in men, but not in women (predicted 15% of variance). In studies 2 (male varsity hockey players) and 3 (male professional hockey players), individual differences in the facial width-to-height ratio were positively related to aggressive behaviour as measured by the number of penalty minutes per game obtained over a season (predicted 29 and 9% of the variance, respectively). Together, these findings suggest that the sexually dimorphic facial width-to-height ratio may be an ‘honest signal’ of propensity for aggressive behaviour.

1. Introduction

Most studies that have investigated facial characteristics and sexual selection have focused on what is perceived as attractive to an observer (Rhodes 2006). Some evidence suggests that certain facial judgements may reflect inherent processing mechanisms in that newborns' preferences for faces parallel those of adults (e.g. Langlois et al. 1987 Slater et al. 2000). Although judgements of attractiveness also are influenced by experience (e.g. Peskin & Newell 2004), perception of attractiveness is thought be part of human evolutionary heritage, perhaps as an honest signal of health (Thornhill & Gangestad 1999). Sexual dimorphism in the face is one such signal that may have been shaped by intra- and intersexual selection (Little et al. 2008). For instance, men with masculine facial features may have obtained increased access to valued resources (i.e. resources important for survival and reproduction) because they are regarded as socially and physically dominant by their rivals (Mueller & Mazur 1996 Swaddle & Reierson 2002). Also, facial masculinity is generally found attractive in men, perhaps serving as an honest signal of health (Rhodes 2006 Rhodes et al. 2007). Further, a recent study found a positive correlation between salivary testosterone concentrations and ratings of facial masculinity (Penton-Voak & Chen 2004). The immunocompetence handicap hypothesis posits that testosterone is responsible for the development of male secondary sex traits (e.g. facial masculinity), but it also has a negative impact on the immune system (Folstad & Karter 1992). Therefore, only high-quality (i.e. healthy, good ‘genes’) men can afford to display these characteristics without suffering the costs of parasite loads (Folstad & Karter 1992).

In addition to providing information as to the personality and health of a target, some recent studies suggest that characteristics of the face may also provide cues as to the behavioural tendencies of the target. For example, women's judgements of the extent to which a man was interested in infants based on his face predicted his actual interest in infants (as measured in a laboratory task Roney et al. 2006). Raters' judgements of facial masculinity (Rhodes et al. 2005) and dominance (Mazur et al. 1994) predicted sexual behaviour of men. People also show some accuracy at identifying ‘cheaters’ in a Prisoner's Dilemma game based on facial photographs (Verplaetse et al. 2007). Together, these findings suggest that people can make accurate inferences about others' personality traits and behavioural dispositions based on certain signals conveyed by the face. The precise facial metrics used to make these trait judgements are not well understood (Danel & Pawlowski 2007). Recently, Weston et al. (2007) described the facial width-to-height ratio, a sexual dimorphism in the structure of the face that was independent of body size, from a morphometric analysis of an ontogenetic series of skulls. In brief, males and females were found to have different growth trajectories that diverge at puberty for bizygomatic width and not for upper facial height, leading to a width-to-height facial dimorphism (greater ratio in men than in women) that is independent of increased body size. The sex difference in the facial width-to-height ratio emerged around puberty, which is when sex differences in facial structure related to body size appear, in part due to increased testosterone concentrations at puberty in boys (Verdonck et al. 1999). Thus, the sexual dimorphism in facial width-to-height may reflect a sexual selection pressure that is independent of selection for body size.

Here, we conducted three studies to examine the extent to which the face width-to-height ratio predicted dominance and aggressive behaviour. In study 1, we first examined whether the facial width-to-height sexual dimorphism, previously described in skulls (Weston et al. 2007), can be found in the photographs of faces. We also investigated the extent to which within-sex variability in the width-to-height ratio in the upper face was associated with within-sex variability in a sexually dimorphic personality trait, dominance, and in behavioural aggression. Dominance and aggression were chosen as measures because facial signals of dominance and/or aggression may not only influence mate preference (intersexual selection), but may also be important signals moderating intermale behaviour (intrasexual selection). For studies 2 and 3, we examined whether a relationship between individual differences in the facial width-to-height ratio would predict aggressive behaviour outside of a laboratory setting. The association between facial width-to-height ratio and aggressive behaviour (defined as the number of penalty minutes obtained per game) was tested in male varsity hockey players (study 2) and in professional ice hockey (Canadian teams in the National Hockey League (NHL) study 3).

2. Material and methods

(a) Participants

In study 1, 88 undergraduate students (37 men and 51 women mean age=18.98 years, s.d.=1.15) took part for course credit and a $5 honorarium. Eighty-two per cent of the participants self-identified as Caucasian, with the remaining 18 per cent representing a diversity of ethnicities. All procedures of the study were approved by the university's ethical review committee.

(b) Face ratios

In study 1, photographs were taken with a Nikon D50 digital camera. ImageJ (NIH open-source software) was used to measure the distance between the lip and brow (height of upper face) and the left and right zygion (bizygomatic width) of the digitized images, based on Weston et al. (2007 figure 1). Inter-rater reliability was high for all measures (distance between left and right zygion: r=0.996, p<0.001 distance between the lip and brow: r=0.989, p<0.001 width-to-height ratio: r=0.985, p<0.001).

Figure 1 An example of the measures used for facial width-to-height ratio. Vertical lines represent the distance between the left and the right zygion (bizygomatic width). Horizontal lines represent the distance between the upper lip and brow (upper facial height).

For study 2, photographs were obtained from 21 undergraduate male varsity hockey players (mean age=22.81 years, s.d.=1.29) from the university's website (all players whose pictures were available except for goalkeepers because these individuals are typically not in a position to obtain penalties, the measure of aggression) and measured as in study 1. All the pictures were facing forward however, some individuals did not have a neutral expression (i.e. some were smiling). All measurements had good inter-rater reliability (facial height: r=0.98, p<0.001 facial width: r=0.94, p<0.001 width-to-height ratio: r=0.90, p<0.001).

For study 3, photographs were obtained for every player who played on the Canadian teams of the NHL during the 2007–2008 season (Calgary Flames, Edmonton Oilers, Montreal Canadiens, Ottawa Senators, Toronto Maple Leafs and Vancouver Canucks) whose pictures were available on the Entertainment and Sports Programming Network (ESPN) website (n=126). Two pictures had to be excluded because the individuals were not facing forward and the tilt of the head would compromise the measurement of the facial width-to-height ratio. Further, we excluded photographs from goalkeepers (n=12) because these individuals are typically not in a position to obtain penalties (the measure of aggression). The final sample was n=112. Facial width-to-height ratios were calculated as in studies 1 and 2. All measurements had good inter-rater reliability (facial height: r=0.97, p<0.001 facial width: r=0.996, p<0.001 width-to-height ratio: r=0.96, p<0.001).

(c) Trait dominance

Participants completed a 10-item questionnaire assessing trait dominance (International Personality Item Pool scales Goldberg et al. 2006). Some examples of items include ‘Like having authority over others’ and ‘Want to be in charge’. Responses were scored on a Likert scale ranging from −2 (very inaccurate) to +2 (very accurate), and had high reliability (Cronbach's alpha=0.82).

(d) Point Subtraction Aggression Paradigm

To measure aggressive behaviour, we used a modified version of the Point Subtraction Aggression Paradigm (PSAP Cherek 1981). This measure is positively correlated with various self-report measures of aggression (Gerra et al. 2007 Golomb et al. 2007). In brief (see also Carré & McCormick 2008), participants were led to believe that they would be paired with a same-sex partner (in actuality, an E-Prime computer program) on a task that required them to select among three response options to earn points that would be exchangeable for money. Pressing response option no. 1 a hundred consecutive times would cause the point counter on the screen to enlarge, flash several times with positive signs around it, and increase the point counter total by one. It was explained to participants that the point counter might flash several times with negative signs around it, resulting in a one-point decrease in the point counter total. They were told that this meant that their partner (actually the computer program) had stolen a point, and each stolen point would be added to the partner's counter. Participants could respond by continuing to select option no. 1 (point reward) or could switch to option no. 2 or 3. Pressing option no. 2 ten times would steal a point from their partner however, participants were instructed that they were randomly assigned to the experimental condition whereby they, unlike their partner, would not keep any points stolen. Pressing option no. 3 ten times would protect their point counter against theft of points for a brief time. Thus, the dependent variables from the PSAP measure were option nos. 1 (reward earned), 2 (aggression) and 3 (protection). Selection of option no. 2 was considered reactive aggression because the participants did not increase reward, and in fact lost opportunity to increase reward, each time option no. 2 was selected.

(e) Study 1 procedure

Participants arrived in groups of two or four and first completed a demographic and trait dominance questionnaire. Next, participants were photographed while in a seated position and maintaining a neutral facial expression. Participants were escorted to separate rooms for the PSAP procedure. The PSAP took approximately 40 min to complete, after which they completed a brief questionnaire designed to assess whether they were aware of the deception used in the experiment. Responses confirmed that participants believed that they were playing against another person.

(f) Aggression measure in studies 2 and 3

The penalty minutes that each player accrued per number of games played during the 2007–2008 season (obtained from the Ontario University Athletics website for study 2 and from ESPN's website for study 3) were used as the measure of aggression. Penalties included behaviours such as slashing, cross-checking, high-sticking, boarding, elbowing, checking from behind, fighting and so on. These behaviours meet the classic definition of aggressive behaviour as any act that is intended to harm another individual, who, in turn, is motivated to avoid the behaviour (Baron & Richardson 1994).

(g) Statistics

Gender differences in trait dominance and facial width-to-height ratio were examined using multivariate analysis of variance (MANOVA), with follow-up t-tests. Multiple linear regression analysis was used to examine the relationship between predictor variables (trait dominance, facial width-to-height ratio and trait dominance by facial width-to-height ratio interaction) and aggressive behaviour as measured by the PSAP. The main assumptions underlying linear regression (e.g. outliers, linear relationship between predictors and criterion, multicollinearity, independence of observations, homoscedasticity and errors normally distributed) were examined and were all met. Also, Pearson's correlation coefficients were computed to examine the bivariate association between the facial width-to-height ratio and aggressive behaviour in varsity and professional ice hockey players. All analyses conducted were two-tailed and the level of significance was set at p<0.05.

3. Results

(a) Study 1

Tests for gender differences in trait dominance, facial ratio and aggressive behaviour consisted of MANOVA and follow-up t-tests. There was a main effect of gender (F5,82=3.04, p=0.01): men had a greater facial ratio (t86=2.33, p=0.02, Cohen's d=0.50) scored higher on trait dominance (t86=2.15, p=0.04, Cohen's d=0.46) and were more aggressive than women (t86=2.18, p=0.03, Cohen's d=0.47). Men and women did not differ in reward (t86=−0.80, p=0.43, Cohen's d=0.18) or protection (t86=0.66, p=0.51, Cohen's d=0.15) responses (table 1).

Table 1 Mean (s.e.m.) for women (n=51) and men (n=37) for each of the variables measured in study 1.

Separate regression analyses for men and women were computed with trait dominance and face ratio as predictors of aggressive behaviour. For men, face ratio predicted 15 per cent of unique variance in aggressive behaviour (R 2 =0.18, F2,34=3.60, p=0.04 t36=2.50, p=0.02 figure 2), but trait dominance was not a significant predictor of aggression (p=0.27). Furthermore, the face ratio by trait dominance interaction was not significant (Rchange 2 =0.001, F1,33=0.04, p=0.84). For women, face ratio and trait dominance did not predict aggressive behaviour (R 2 =0.03, F2,41=0.66, p=0.52), nor did the interaction (Rchange 2 =0.003, F1,40=0.14, p=0.72).

Figure 2 Scatter plot depicting the relationship between face width-to-height ratio and aggressive behaviour in undergraduate men (n=37, r=0.38 and p=0.02).

(b) Study 2

Individual differences in face ratio in male hockey players explained 29.2 per cent of the variance in penalty minutes per game played (r=0.54, p=0.01 figure 3).

Figure 3 Scatter plot depicting the relationship between face width-to-height ratio and aggressive behaviour (penalty minutes per game) in male varsity hockey players (n=21, r=0.54 and p=0.01).

(c) Study 3

Individual differences in the face width-to-height explained a significant proportion of the variance in aggressive behaviour (r=0.30, p=0.005) in NHL hockey players. Separate correlation coefficients were also computed for each individual team (figure 4). All correlation coefficients were in the positive direction and ranged from 0.17 to 0.51.

Figure 4 Scatter plots depicting the relationship between face width-to-height ratio and aggressive behaviour (number of penalty minutes per game played) in male professional hockey players for the six Canadian teams in the NHL (n=112) as a group (a) and for each individual team (bg): (a) all Canadian NHL teams (r=0.30), (b) Calgary Flames (r=0.17), (c) Edmonton Oilers (r=0.20), (d) Montreal Canadiens (r=0.39), (e) Ottawa Senators (r=0.51), (f) Toronto Maple Leafs (r=0.37) and (g) Vancouver Canucks (r=0.24).

4. Discussion

In sum, a sexually dimorphic width-to-height ratio (men>women) in the upper face was evident in the photographs of an unselected sample of undergraduates, and this ratio predicted aggression in men assessed in a validated laboratory behavioural task and in a naturalistic setting (varsity and professional ice hockey players). Weston et al. (2007) first reported the sexually dimorphic facial width-to-height ratio in an analysis of a series of human skulls representing different stages of ontogeny. They found that the sex difference emerged around puberty, which is when sex differences in facial structure related to body size appear, in part due to increased testosterone concentrations at puberty in boys (Verdonck et al. 1999). This finding is consistent with a recent study demonstrating a positive correlation between salivary testosterone concentrations and ratings of facial masculinity (Penton-Voak & Chen 2004). The sex difference in the facial ratio observed in skulls was independent of body size and of other size-related facial variation, and thus suggests that this sexual dimorphism may reflect a selection pressure that is independent of body size (Weston et al. 2007). A similar sexual dimorphism in the face, which was independent of body size, was also reported in chimpanzees (Weston et al. 2004).

The data obtained here suggest that for men variation in the width-to-height ratio from neutral faces may be an honest signal of propensity for aggressive behaviour. Clearly, an angry facial expression is a direct way to communicate one's emotional state and behavioural intent. However, it remains possible that subtle cues from a neutral face may have been selected because they provide information as to an individual's behavioural dispositions. Notably, angry facial expressions consist of lowering the brow and raising the upper lip, a pattern of muscle activity that increases the facial width-to-height ratio. From an evolutionary perspective, these findings suggest that selection pressures may have shaped the perceptual system to be especially attuned to cues of threat and/or aggression. However, it will be important to examine the extent to which people are sensitive to individual differences in facial width-to-height ratio and whether this facial metric is used to guide behaviour. Another possibility is that the relationship observed between the facial metric and aggressive behaviour was partly influenced by the posture of the head in the photographs (e.g. more aggressive men may tilt their head upwards and thereby foreshorten the vertical measurement of the face). It is also possible that stronger relationships would have been observed between the facial ratio and aggressive behaviour if direct measurements of the face were made instead of using photographs and had we been able to control facial expression in the faces of the hockey players.

There was no relationship between trait dominance and aggressive behaviour in our sample, although individual differences in trait dominance were associated with self-report measures of trait aggression in both men and women in other studies (Archer & Webb 2006 Johnson et al. 2007). This disparity may reflect that the PSAP is a behavioural measure designed to assess situation-specific reactive aggression, whereas the other studies measured a broader range of aggression (physical, verbal, hostile and anger) across several situations using self-report. However, the higher trait dominance in men than in women found here is consistent with previous studies using similar self-report measures (Budaev 1999 Costa et al. 2001). Furthermore, the sex difference in aggressive behaviour on the PSAP is consistent with that reported in the literature (reviewed in Archer 2004). The fact that there were no sex differences in reward or protection responding on the PSAP suggests that men were equally motivated to earn reward and avoid punishment (i.e. point subtractions).

There is much research literature addressing the role of the face in social interactions, and there is some literature indicating that faces can be used to gauge certain personality traits above chance (e.g. Penton-Voak et al. 2006). Such judgements are made in less than 40 ms, made with high consistency and have some predictive values (Bar et al. 2006 Willis & Todorov 2006 Ballew & Todorov 2007). For example, women's judgements of the extent to which a man was interested in infants based on his face predicted his actual interest in infants (Roney et al. 2006). Judgements of competence, intelligence and leadership based on only the facial appearance of political candidates (and independent of age and attractiveness) predicted the outcome of the elections (Todorov et al. 2005). Judgements of dominance predicted career success (Mueller & Mazur 1996) and age at first copulation (Mazur et al. 1994). Another study reported that participants' judgements of the personality traits of power (competence, dominance and facial maturity) and warmth (likeability and trustworthiness) in the faces of CEOs of Fortune 500 companies predicted the profits of the CEO's company (Rule & Ambady 2008). However, whether the actual success of the individuals whose faces were judged is partly due to shared societal stereotypes (e.g. the success of attractive people is in part because they are judged as more intelligent Zebrowitz et al. 2002) continues to be debated.

The novel finding of the present study is that individual differences in facial characteristics predict behaviour: Variability in a sexually dimorphic facial metric in men, which is independent of body size, predicted aggressive behaviour in a laboratory setting and in male hockey players. The relationship between within-sex variation in facial width-to-height and aggressive behaviour might reflect a common relationship to a third variable, such as organizational effects of testosterone as part of sexual differentiation in adolescence, which influences both the development of the physique and the nervous system (reviewed in Sisk & Zehr 2005 McCormick & Mathews 2007). The relationship between facial morphology and aggressive behaviour suggests that this characteristic may be an honest signal, perhaps comparable to honest signals in other species that predict factors such as phenotypic quality (Vanpe et al. 2007) or aggressive intent (Morestz & Morris 2006 Laidre & Vehrencamp 2008).

All procedures of the study were approved by the university's ethical review committee.


The Psychology of Beauty

Recent debate on female body attractiveness has centered around the relative contributions of body-mass index (weight/height 2 : BMI) and waist-hip ratio (circumference of narrowest part of waist/circumference of widest part of hips/buttocks: WHR) on evaluations of female body attractiveness. The results from direct comparisons are consistent: BMI influences attractiveness ratings more than WHR.

Using scanned, rotating 3D images of Caucasian female figures as stimuli and attractiveness ratings made by Chinese students, Fan and colleagues (2004) published the following scatter plot (these plots show the male ratings only – there was no significant difference in the female ratings) of WHR and attractiveness rating (AR):

Several things are apparent:

Having created 3D scans of their stimuli, Fan and colleagues were able to calculate the actual volume of each woman’s body. This calculation enabled them to introduce a third ratio: volume height index (body volume/chin height 2 : VHI). Given that BMI is an inexact estimate of body size/shape, it is likely that a more precise ratio: like body volume and height (at the chin) would predict attractiveness more precisely than BMI. And this is exactly what was found: Log(VHI) accounted for approximately 90% of the variance in attractiveness ratings in this study. A subsequent study (Fan et.al., 2007), that included digitally created, low-VHI bodies found the optimal female volume/height index to be approximately 14 liters/meter 2 .

Other factors contribute to female body attractiveness: leg length, waist, hip, and bust proportions, but these features seem to enter raters’ consideration after a preliminary analysis of body size.

Current data does suggest that size cues take priority over secondary sexual characteristic cues in evaluations of body attractiveness. It is tempting to suggest that size matters more than shape in evaluating female body attractiveness – but any statement of this sort would be premature. It is unlikely that perceivers estimate body size without utilizing shape cues and unclear what role secondary sexual characteristic cues play in this estimate. Perhaps eye-tracking studies are an appropriate next step?


Fan, J., Liu, F., Wu, J., & Dai, W. (2004). Visual perception of female physical attractiveness Proceedings of the Royal Society B: Biological Sciences, 271 (1537), 347-352 DOI: 10.1098/rspb.2003.2613

Fan, J., Dai, W., Quan, X., Chau, K., & Liu, Q. (2007). Effects of shape parameters on the attractiveness of a female body. Perceptual and Motor Skills, 105, 117-132 PMID: 17918555


The Facial Width-to-Height Ratio Predicts Sex Drive, Sociosexuality, and Intended Infidelity

Previous research has linked the facial width-to-height ratio (FWHR) to a host of psychological and behavioral characteristics, primarily in men. In two studies, we examined novel links between FWHR and sex drive. In Study 1, a sample of 145 undergraduate students revealed that FWHR positively predicted sex drive. There were no significant FWHR × sex interactions, suggesting that FWHR is linked to sexuality among both men and women. Study 2 replicated and extended these findings in a sample of 314 students collected from a different Canadian city, which again demonstrated links between the FWHR and sex drive (also in both men and women), as well as sociosexuality and intended infidelity (men only). Internal meta-analytic results confirm the link between FWHR and sex drive among both men and women. These results suggest that FWHR may be an important morphological index of human sexuality.

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