“In a U.S. sample, thinness is so highly valued that 24% of women and 17% of men “would surrender three years of their lives to be thinner.””

Gangestad, Steven W. and Glenn J. Scheyd. 2005. “The Evolution of Human Physical Attractiveness.” Annual Review of Anthropology. Vol.35, pp.523-548.

“The Evolution of Human Physical Attractiveness,” by Steven W. Gangestand and Glenn J. Scheyd: A Long Blog Post.  All data in this blog comes from this article, written in 2005.  Statements written in italics are my thoughts and interpretations of this work.

Introduction

Researchers randomly paired college men and women for a blind date.  In return, participants filled out personality and interest measures, background questionnaires, and a survey following the date.  A key question was whether they were interested in a subsequent date with their partner.  Only one variable- added as an afterthought- reliably produced interest: their partner’s physical attractiveness.

Attractive people have greater choice in mating markets and hence are able to secure consensually more desired partners.  But attractive people are treated differently from others more generally, leading them to have better jobs, higher incomes, and more friends than others- indeed, achieve more desirable outcomes in most spheres of life people consider important.  Look at the successful men and women in Hollywood.  Very few movie stars, TV celebrities, or singers can be considered unattractive.  They amas a great deal of wealth and are set apart from the rest of “normal” society.  Biases happen in the “real world” too.  I’m sure many people, including myself, have been passed over for a job or position; come to find out that the person who got the job was an attractive woman. 

Buss (1989) surveyed people from 37 cultures around the world about mate preferences.  The US samples rated the importance of physical attractiveness only slightly above average for the cultures.  I think this is because of the media.  It shapes what we see as beautiful.  If we weren’t exposed to pictures of anorexic movie stars who are labeled as beautiful, there wouldn’t be as many problems with anorexia or girls and boys with self-esteem issues.

Symon’s (1979) “Evolution of Human Sexuality” offered the first intensive analysis of physical attraction as an outcome of natural selection.  Research guided by evolutionary thinking has steadily intensified over the past 15 years.  Since 1990, nearly 300 articles with the keywords “physical (or facial) attractiveness” as well as “selection” or “evolution” in their titles or abstracts have appeared in scientific journals.  Again, I believe that because of the media, we as a society are more concerned with physical attractiveness than in the past.

Basic Concepts

Traits: refer to aspects of organisms’ phenotypes.  Phenotype is defined as the observable properties of an organism that are produced by the interaction of the genotype and the environment.  Genotype is defined as all or part of the genetic constitution of an individual or group.  A liberal definition allows a trait to be any aspect of the phenotype that can be discriminated on the basis of any criterion its causes, effects, appearance, etc.- and includes dispositional traits.

Adaptation: two meanings- 1. it is the process by which natural selection modifies the phenotype and generates traits whose effects facilitate the propagation of certain genes over others, thereby causing evolution. 2. it also refers to the end-products of that process- i.e. the traits that have been constructed by a process of phenotypic modification by natural selection for a specific gene-propagating effect.  An effect refers to the way, or ways, in which an aspect of the phenotype interacts with the environment.  A function is an effect that caused the trait to evolve- that is, an effect that enhanced the reproductive success of the trait’s bearers over others lacking the trait.  (The function of the eyes is to see, the function of wings is to fly)

Byproducts: A small minority of traits qualify as adaptations.  Byproducts evolved merely because they were linked with other traits that had beneficial effects and hence were carried along with selection for adaptations.  The example given is vertebrate animals evolved skeletal systems of calcium phosphate (perhaps ancestrally for the function of storing calcium, but modified for the function of structural rigidity necessary for locomotion.)  Calcium phosphate is white and hence so too are bones.  The whiteness of bones, however, is not an adaptation.  It is the byproduct of selection for other properties of calcium phosphate.

Energetic trade-offs: Organisms can be thought of as entities that capture energy from the environment (foraging, hunting, cultivating) and allocate it to reproductive and survival-enhancing activities.  Allocation of finite energy and time budgets entails trade-offs and hence forces decisions about the relative value of possible ways to spend energy.

The special design criterion for identifying adaptation: Evolutionary biologists are interested in understanding adaptation.  Because adaptations don’t come with labels, however, their identification requires inference.  The major criterion used is special design.  Just as wings and eyes are telltale signs of historical selection for flight and seeing, respectively, certain physiological features of humans (e.g. patterns of attraction to mates and their features) may be telltale signs that particular selection pressures shapes the minds of ancestral humans (e.g. selection of a signaling system due to particular benefits associated with the signal).

Attractiveness and beauty as an outcome of adaptation: Individuals find other individuals attractive as a result of the latter possessing specific favored traits.  Once individuals of one sex prefer particular qualities, the preferences exert selection pressures on the prefered traits.  Individuals who possess prefered traits, by virtue of their enhanced ability to exercise choice in a mating market, have greater reproductive success.  Selection hence leads individuals to expend energy and time to display favored traits.  This reminded me of many women who spend an hour in the bathroom getting ready for a date.  They must have the right hair to accentuate their neck, the right dress to accentuate their legs, the right make-up to accentuate their eyes and lips.  This also leads to modifications which will be discussed later.

Charles Darwin himself recognized (1871), such selection can in theory lead to evolution of extravagant ornaments, even those detrimental to an animal’s viability, provided they have sufficient advantage in the realm of mating.  I thought of peacock feathers.  Male peacock’s have developed extravagant feathers in order to attract a mate.  The more extravagant the feathers, the more successful the male is at reproductive success.  However, the more extravagant his feather, the less he can fly.  Hence, he is easily made dinner by a predator.

Sexual Selection and Signaling Theory: The coevolution of preferences and prefered traits can be thought of as the evolution of a signaling system, which entails that one sex (signallers) posses signals and the other sex (receivers) possess psychological (cognitive and motivational) capacities to perceive and act upon (e.g. be attracted to) those signals. Quality or condition refers to an individual’s ability to successfully interact with the environment to acquire and effectively expend energetic resources.  Superior condition has been associated with the concept of health.  The concept of heath is much broader than simply the absence of disease; it implies greater phenotypic fitness or resourcefulness.  We talked about the fitness of species in ANTR 110 so this was an easy concept to grasp.  Fitter genes to pass onto offspring and a greater ability to provide for those offspring, insuring their survival.

The article then launches into a whole lot of things I didn’t quite understand as it was very technical and scientific in nature.  But what I got from it was they were using fancy words to describe how those that are considered attractive mates can have larger faults than those that are less attractive and even with larger faults, they will still have more reproductive success.  This of course made sense to me since it is very common for attractive men and women to be terrible people and yet they still seem to be more successful.  They also seemed to have fancy speech for discussing chemistry between people or animals but it was very confusing.  But then we get into something that I found VERY interesting.

Genetic versus Direct Benefits: Female preferences may vary depending on whether they are selecting a social partner or an extrapair partner.  In collared flycatchers on the island of Gotland, for instance, females have no clear preference for males having a relatively large forehead patch, an honest signal of quality.  When choosing extrapair partners, however, females clearly prefer large-patched males.  This rang so true for women.  Women may choose good-looking males for a short-term relationship but looks are not the deciding factor when choosing a husband.  Women will marry less attractive men for many more reasons than just sex such as companionship, friendship, security, wealth, etc…

Mutual Male Choice: In many species, sexual selection on signals is much greater in one sex than the others.  In mammalian species, females are typically a limiting reproductive resource and, hence, males compete through intersexual competition and through signaling for females.  Selection on female signaling is much weaker, as males may seldom turn down sexual opportunities with females.  This made me laugh.  they are basically saying that women don’t have to try very hard to get men.  My husband used to tell me this all the time- said it was so unfair.

Features Associated With Physical Attractiveness

3 facial features across cultures: sexual dimorphism, averageness, and symmetry.  As well as female waist to hip ratio and male body type.

Facial sexual dimorphism: Men’s chins are longer and broader than women’s, development of the brow ridge renders men’s eyes smaller (relative to face size) and narrower than women’s.  Women’s cheekbones are more gracile and their lips fuller.  During adolescence, testosterone promotes growth on the lower face and estrogen may cap growth on bones, contributing to sexual dimorphism.

Men prefer female faces with relatively small chins, large eyes, high cheekbones, and full lips.  RV, reproductive value is the expected residual reproductive success of an individual, generally based on age.  RV is maximal when women reach reproductive age and diminishes thereafter.  As women age, their facial proportions become less feminized.  Men’s preference for facial femininity then, could reflect selection for age-based RV.

Females actually do not have a clear preference.  Studies have found a preference for masculine faces, feminine faces, and no clear preference for either one.

Across a variety of cultures, men with masculine faces are perceived to be and probably are socially dominant.  Kung San bushmen with broad chins and robust bodies have relatively high reproductive success.  This also rang true to me.  Successful men, on average, seem more masculine, have a dominant aire around them.  The man’s man type- the John Wayne’s.  Taller men are statistically more successful than shorter men.

If male facial masculinity varies with condition, as conjectured, why do women not consistently prefer masculine faces?  Penton-Voak et al. (1999) speculated that women face a trade-off: Although more dominant and possibly more fit, masculine men may be less willing to invest exclusively in partners and help care for offspring.  Just as female collared flycatchers do not particularly prefer males with large forehead patches as social partners, women do not prefer more masculine men as mates.  As this view expects, men with feminine faces are perceived to be warmer, more agreeable, and more honest than men with masculine faces.

Women’s preferences vary across their ovulatory cycles.  Basically this paragraph talked about the more fertile a woman is in her cycle, the more she is looking for a “fit” partner with good genes that could be passed onto offspring.  this was an interesting way of explaining why at some times of he month, women are more inclined to go looking for a mate.  That seems to be the most delicate way of putting it.

Facial Average and Facial Symmetry: The article basically explained that there is a basic familiarity with facial construction.  Norms.  This is what can be labeled as average and it is what most men find attractive.  Deviations from average are most often considered unattractive and they discussed genetic alterations and mutations of genes.  Symmetry is described in a similar way.  That while each side of the face is not exactly symmetrical, most of the time, each half is pretty close.  It is when they are asymmetrical that a person or animal is considered unattractive and again, they gave examples of genetic alterations.

Female Body Form:

In 1993, Singh proposed that, although preferences with respect to female body weights vary cross-culturally, men universally prefer women with low waist-to-hip ratio (WHR).  The primary benefit of this preference may ancestrally have been the same as a benefit of a preference for feminine faces: Low WHRs reflect a history of energy balance and flux that promotes allocation of energy into reproductive efforts.  Quite possibly, reproductive women’s tendency to store fat on the hips and breasts evolved as adaptations for creating a low center of gravity appropriate for carrying fetuses and babies and putting fat where it can be readily converted for lactation.

Male Body Form: Dixon et al. (2003) found that women in both Britain and Sri Lanka prefer lean, muscular (mesomorphic) body types most, followed by average and then skinny body types, heavy (endomorphic) body types are the least prefered.  Women also prefer men with broad shoulders, relative to waist or hip size (i.e. a “V-shaped” torso), average WHRs, and possibly chest hair.  A number of potential benefits could explain these preferences: physical protection, nutritional resources, and positive externalities of male status, as well as indirect genetic benefits to offspring.  Women particularly prefer masculinity in men as short-term partners, again, in particular when ovulating.  Interesting that women favor masculinity in body traits but less so in facial traits…

Body Modification:

To the extent that one can produce the signals that have been recurrently associated with high mate quality throughout the history of our species, he or she will activate, in potential mates, their psychological adaptations for choosing suitable mates.  These adaptations are vulnerable to deception, and humans have found innumerable ways of modifying their bodies to just this effect.  A wide range of methods, from the quotidian (diet and exercise) to the absurd (e.g. buttock’s implants), may be understood as techniques of enhancing the strength of mate value signals.   The article then goes on to explain how body modification has been going on for thousands of years.  Apparently, deadly night shade was used 2000 years ago to dilate the eyes and enhance eye appearance.  Now they use Botox for all sorts of facial procedures.  And women use these things more often than men because men throughout the world are more concerned with women’s physical attractiveness than vis versa, and women who look relatively young are consistently rated as attractive.  Hair, hair loss, and hair removal were also talked about.  Healthy hair on a person’s head is very valuable and in many ways is part of a person’s identity.  But women do not like hair on their legs and underarms, and many women have all of their body hair removed because “it is ugly”.  They also discuss corsets, girdles, and other sculpting undergarments which I discussed in a previous blog post and it goes back tot he issue of the WHR and the statistic I used as the title of this blog post. 

The article goes on to talk about preferences and not in so many words basically says that people date within their comfort zone; 10’s date 10’s and 5’s date 5’s.  Or somewhere close to those ranges.  The term “out of your league” came to mind when I was reading about men and women saying who they were and were not attracted to.

Overall, I thought it was a good article.  Sometimes difficult to understand but it rings true with many of the stereotypes that we have today about men and women.  After all, stereotypes are most often based on some sort of fact.

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About jenahmoody

I am a wife and mother. I am a former Fire Controlman in the US Navy. I am a Criminal Justice major at Old Dominion University. I love to cook and watch movies with my family.
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