The Effect of Facial Symmetry on Human Attractiveness
Abstract
Many studies have examined the effect of facial symmetry on human attractiveness.
Researchers have found that small deviations from perfect bilateral symmetry have been shown
to negatively affect ratings on facial attractiveness (Grammer and Thornhill, 1994). We
investigated how facial symmetry affected students’ ratings of attractiveness. Loras College
students were shown a PowerPoint of these faces and were asked to rate them on a scale of one
to ten, one being not attractive and ten being very attractive. We compared scores calculated by
the program anaface.com for fifteen male faces and fifteen female faces to the scores given by
Loras College undergraduate students evaluating these pictures. Anaface.com is an online
program that measures seventeen facial points and calculates an overall facial attractiveness
score based on symmetry. At the end of the study, we found no correlation between the
anaface.com score and what Loras College students considered attractive. However, in isolating
gender, we found that Loras College females that rated male pictures were significantly
correlated with the anaface.com rating of males. Loras College males that rated female pictures
were not significantly correlated with the rating of female faces from anaface.com. We also
found there was a general agreement among genders in rating the pictures. Using pictures of both
genders, we found that the Loras College male and female students’ ratings were significantly
correlated, the same was found when we isolated female pictures. In contrast, we found that the
Loras College male students’ ratings were not significantly correlated with the Loras College
female students’ ratings for the male pictures. Researchers need to minimize participants taking
the survey together to eliminate skewed opinions.
Introduction
Every human face has certain characteristics that impact human attractiveness. Facial
features are determined in humans by prenatal sex steroids during fetal growth (Grammer et al.,
2012). Many experiments have evaluated these facial characteristics and how they may affect
social behavior towards individuals. This social behavior would include a teacher’s behavior
towards students, employment, marriage success, jury decisions, and other human encounters
(Cunningham, 1986). Evolutionarily, women with more symmetrical faces tend to have more
biological offspring than women with less symmetrical face (Grammer and Thornhill, 1994).
Subsequently, the facial symmetry of women correlates with the number of children they give
birth to in a hunter and gatherer society (Grammer et al., 2012). These interactions put an
important emphasis on an individual’s face, which is why many studies have examined how
facial symmetry affects human mate preference. Facial features in human beings have specific
characteristics that define bilateral and asymmetrical facial features (Grammer and Thornhill,
1994). Facial symmetry can be measured and converted into an overall score. The more
symmetrical a face, the higher the score. In our experiment, we observed what dimensions and
symmetry people preferred in deciding if someone was attractive. Our hypothesis was that facial
symmetry affects the attractiveness of human beings. We expect this because certain facial
symmetry could be intrinsically attractive (Cunningham, 1986). The computer software,
anaface.com, determined the symmetry of the faces and gave them a rating out of ten. We then
observed the sample data to see if our participants’ opinions of attractiveness corresponded with
the data from anaface.com.
Methods
This study was conducted at Loras College located in Dubuque, IA. Loras College
currently has about two thousand students enrolled. For our experiment, we surveyed seventy
Loras College undergraduate students to participate in our research. These surveys were given to
participants in the residence halls, the cafeteria, and the science hall.
First, thirty pictures, fifteen males and fifteen females, from the Baldwin Wallace
University men’s and women’s soccer roster were analyzed for facial symmetry on anaface.com.
This program marks the horizontal midline of the mouth, the horizontal midline of the outer and
inner eye corners, and a vertical line from the tip of the forehead to the chin to create seventeen
specific points to measure facial symmetry. These seventeen points were analyzed to compute
one score for attractiveness based on the facial symmetry. All of these student athletes from
Baldwin Wallace University signed an NCAA waiver allowing their pictures to be used in this
experiment. The pictures included both men and women that are the same age as the Loras
College students who participated in this study. Next, the pictures were placed in a PowerPoint
and shown one picture at a time to the seventy students, thirty-one of which were males and
thirty-nine were females, from Loras College who were willing to participate in the study. These
participants signed a consent form and were also asked to put their grade and gender on the top
of their ratings sheet. The participants rated each face on a scale of one to ten. To analyze the
data, we used SPSS to find the Pearson Correlation and linear regression. These results looked at
how attractive the participants rate the people in the pictures compared to their anaface.com
symmetry rating.
Results
Anaface.com scores ranged from 5.44 to 8.32 for men and 5.93 to 8.64 for women.
Ratings by Loras students ranged from 1 to 10 for both men’s and women’s pictures. Ratings
given by students who took the survey were not significantly correlated with the anaface.com
scores (t=0.595, df=29, p=0.557; Figure 1). The r2 value indicates that 1.2% of the variation in
student ratings is explained by the anaface.com ratings (r2=0.012). When Loras College male
students’ scores were compared to Loras College female students’ scores, the correlation was
weak but significant (r=0.263, df=1, p<0.001; figure 2). When isolating the gender of the
pictures, Loras College male students’ and Loras College female students’ scores were
significantly correlated for the female pictures but not significantly correlated for the male
pictures (r=0.472, df=1, p<0.001; figure 3; r=0.080, df=1, p=0.083; figure 4). Further analysis
showed that the category of Loras females rating male pictures was weakly, but significantly
correlated with the anaface.com scores (r=0.084, p=0.042, df=1). The ratings of Loras males of
female pictures was not significantly correlated with anaface.com scores (r=0.001, df=1,
p=0.981).
Figure 1- Correlation of ratings given by Loras College student
participants with the scores from anaface.com. N=30 for the average
rating of each picture on the survey.
Figure 2: The correlation of Loras College female students’ scores
with Loras College male students’ scores based on both male and
female pictures.
Figure 3: The correlation of Loras College female
students’ scores with Loras College male students’ scores
based on only female pictures.
Figure 4: The correlation of Loras College female
students’ scores with Loras College male students’
scores based on only male pictures.
Discussion
In this study, the students who took the attractiveness surveys did not base their ratings
solely on facial symmetry. This idea is supported by our observations that attractiveness and
symmetry were not correlated. However, the Loras student’s ratings of attractiveness and
anaface.com’s analysis of symmetry were not significantly different, which suggests that
symmetry played some role in attractiveness, but other factors played a larger role in determining
attractiveness.
There was some agreement between genders in rating the pictures. Male and female
Loras College students both had agreement on rating female pictures, but when it came to the
male pictures there was disagreement among male and female Loras College student ratings. If
everyone had rated each picture objectively, a stronger relationship could have been found.
Another technique that researchers use to look at symmetry and attractiveness is
composite faces. Composite faces are images that have been adjusted to simulate perfect facial
symmetry. It was found that composite female faces were rated as more attractive in comparison
to individual female faces (Kowner, 1996). This is interesting because according to our results,
symmetry was not a contributing factor to attractiveness. Evolutionary trends show that humans
look for certain characteristics in mates that would indicate the ability to produce healthy babies.
The attraction to these characteristics in humans was based on their facial symmetry. These
qualities are still common attractive features in American culture today.
Although we were very thorough in the design and execution of our study, we still found
that we had errors. Some participants took the survey in a group setting while others were by
themselves. We believe that group settings created more negative feedback and participants
were more vocal in their opinions of the pictures in the survey. It is possible that the group
settings could have changed the way that other participants rated the pictures. Men and women
differ in the preferences they have for same-sex and opposite sex attractiveness, and in our study,
there were a few instances where some participants unfairly rated people of the same gender
because they felt they could never find someone of the same sex attractive (Barrett et al., 2002).
To further our study, we would use a larger sample size and provide more images for
people to rate. We would also put more emphasis on selective features to determine which
features people find to be the most influential in determining attractiveness. Physical
attractiveness is becoming an increasingly important quality in our society and has many
different aspects one can look in to. These qualities are not just relevant in humans; there are also
studies that have been conducted on animals to determine if certain characteristics are preferred
by males and females within a species. It has been found that exaggerated sex-typical male traits
are preferred by the females of the species (Clark et al., 2010). This means that attractiveness
matters in determining ideal mates and plays a part in the survival of animals.
Acknowledgements- Thanks to Doctor Daniel Wenny and three anonymous reviewers for helpful
comments on the manuscript. Additional thanks to Doctor Daniel Wenny for help on the graph
and countless hours of ideas and suggestions.
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