Domestication of the Human: The Biology and Psychology of Aesthetics.
A common public point of view that may qualify as a cultural 'truism', is: 'beauty is in the eye of the beholder.' This truism coincides as well with a long held view in the social sciences that standards of beauty are arbitrary cultural conventions (Berry, 2000; Etcoff, 1999). Even Darwin favored this view after observing large cultural differences in beautification practices (Darwin, 1998/1874). However, emergence of preferences early in development and cross-cultural agreement on attractiveness (Cunningham et al. 1995; Ford & Beach, 1951; Rhodes et al. 2001b; Rhodes, 2006; Symons, 1995) challenges both the 'truism' and the traditional viewpoint held by social scientists. At least two observations suggest that some preferences may be part of our biological, rather than our cultural, heritage. First, people in different cultures, social classes, ages, and sexes, generally agree on which faces are attractive (Cunningham et al., 1995; Langlois et al. 2000; Perrett et al., 1994; Perrett et al. 1998; Rhodes et al. 2001b; Rhodes & Zebrowitz, 2002). Second, preferences emerge early in development, before cultural standards of beauty are likely to be assimilated (Geldart et al. 1999; Langlois et al. 1987; Rubenstein et al. 1999; Rubenstein et al. 2002; Samuels et al. 1994; Samuels & Ewy, 1985; Slater et al. 1998; Slater et al. 2000). Further, universally agreed upon features of the human face in females, for example, that are considered more attractive when compared to other facial and physical attributes, have been reported by several investigators (Buss, 2004; Buss, 2012; Ford & Beach, 1951; Kandel, 2012; Petri & Govern, 2013; Rhodes, 2006; Symons, 1995), providing additional support for the 'two observations' asserted above and leading evolutionary psychologists to suggest that such a ubiquitous phenomenon as beauty (attractiveness) may reflect human psychological adaptations and mate preferences (Buss, 2012; Petri & Govern, 2013; Symons, 1979).
Results of a study of features considered attractive in women by Cunningham et al. (1995) reveal that the qualities that influence our judgments of beauty are neither arbitrary nor culture bound. When Cunningham's team asked people of different races to judge the facial attractiveness of Asian, Hispanic, Black, and White women in photographs, he found consistent consensus about who is and who is not considered good looking. In earlier work on attractiveness, Cunningham (1986) found that the physical characteristics of the female face that are rated as attractive by males, include: large eyes, small nose, small chin, prominent cheekbones, narrow cheeks, high eyebrows, large pupils, and a broad smile. Perhaps the classically acknowledged beauty of the Italian actress, Sophia Loren, and the allure of the American actress, Marilyn Monroe, might qualify as embodying the aforementioned celebrated facial characteristics. More recently, research by evolutionary psychologist Buss (2008), confirm the results of Cunningham's team (1995) and adding to Cunningham's (1986) trait-list, Buss includes the following features: large lips, rounded face, facial symmetry, as important qualities that figure into judgments of female attractiveness. Collectively, the aforementioned features serve as cues to which males take note in assessing female reproductive capability and male mate choice (Buss, 2012). Taking into account the results of the aforementioned research on attractive and desirable traits in females, it might be reasonably argued that there are evolved facial, and associated physical characteristics such as woman's waist-to-hip ratio (Singh, 1993), which constitute and inform our notions of what is aesthetically pleasing, attractive, and which serve as physical criteria for what we take into account in our judgment of what is beautiful in a woman.
Thus, this paper proposes that human self-domestication (Barras, 2018; Cieri et al. 2014; Wilkins et al. 2014), bringing about morphological and behavioral changes in an adaptive direction, contribute to the evolved features that enter into our estimation of what is attractive. A further clue as to what influences judgments of physical attractiveness may be provided by an evolutionary approach that suggests that what men desire in a woman is not so much youth and physical attractiveness, per se, but rather features of the female that are associated with reproductive value (Buss, 2012; Ford & Beach, 1951; Symons, 1995). According to Buss, (2012), "Reproductive value refers to the number of children a ... [woman] of a given age ... is likely to have in the future" (p. 141). Reproductive value is typically associated with a youthful, pleasing appearance, embodied in the traits-listings reported above on physical attractiveness (Buss, 2004; Buss, 2008; Buss 2012; Cunningham, 1986; Cunningham et al. 1995; Ford & Beach, 1951; Singh, 1993; Symons, 1995). Thus, judgment as to what is considered attractive in a woman is placed on those attributes (e.g., as reported by Cunningham, 1986; Cunningham et al. 1995) that refer to woman's reproductive capability. The aforementioned attributes, having been selected over the course of evolution, have come to serve for the male as clues to a female's reproductive potential. For example, Ford & Beach (1951), in accessing cross-cultural literature in anthropology on traits constituting female attractiveness, and its bearing on subsequent mate selection in males, noted that several evolved features in females that qualify as attractive are clues for the male in assessing the youth, health, and reproductive potential of the female. These features include: clear, smooth skin, and signs of health. The absence of sores, lesions, poor complexion, facial disfigurement and filthiness, are features considered undesirable in males' assessments of female attractiveness. Furthermore, Ford and Beach (1951) found that all cross-cultural groups surveyed considered good complexion and cleanliness attractive. Clear, unblemished skin signals an absence of parasites, absence of skin-damaging diseases during development, and possibly 'good genes' to withstand disease and heal without infection (Buss, 2012; Singh & Bronstad, 1997). Female faces which have a homogenous color distribution, not splotchy, receive higher attractiveness ratings and are perceived as younger (Buss, 2012; Fink et al. 2006; Fink et al. 2008). Further, Buss (2012), in commenting on the Ford and Beach findings cited above, observed that skin quality indicates a sign of "youth" (p. 147) and it is youth, argues Williams (1975), that is the most important determinant of human female attractiveness. Symons (1979) concurs, explaining that the two major attributes derived from his research on female attractiveness, are health and age, both of which are closely related to 'youth', as it is typically healthy, young women who are more likely to reproduce and raise offspring.
It appears, then, that judgments of attractiveness are related to a cluster of selected and evolved physical features in the female that are deemed reliable indications of a woman's health and reproductive potential. Buss (2012) considers the features listed in the studies cited above (Cunningham, 1986; Fink et al. 2006; Fink, 2008; Ford & Beach, 1951; Singh & Bronstad, 1997; Symons, 1979) to be "universally regarded as attractive" (p. 147), suggesting that these attributes are not arbitrary nor necessarily culture bound.
Facial symmetry is another correlate of female attractiveness. Symmetrical female faces are judged to be healthier than less symmetrical faces (Fink et al. 2006) and facial symmetry is positively correlated with judgments of attractiveness (Buss, 2012; Rhodes, 2006). Thus, female attractiveness and judgments of beauty, according to Symonds (1995), are in the adaptations of the beholder" (p. 112; emphasis added) and that males have an evolved sensitivity (adaptations) to cues suggesting a woman's reproductive capability.
Beauty and Adaptations of the Beholder
Let us turn our attention to reproductive value in females as the former relates to males' judgment of female beauty and correspondingly, mate selection. Firstly, human males cannot ascertain a woman's reproductive value directly as compared to our closest primate relative, the chimpanzee. When the female chimpanzee enters estrus, for example, showing maximal sexual receptivity, the latter is advertised by a number of cues: bright red swollen genitals and scents that are highly attractive to chimpanzee males. Human males, however, show a markedly different form in sensing the mating potential of females. First, women's ovulation is relatively concealed or cryptic and the transition from advertised estrus to concealed ovulation posed a poignant adaptive problem for human ancestral males (Buss, 2012). When ovulation is not advertised, how could males discern a female's reproductive value? The concealment of ovulation shifted the problem from one of detecting when a woman was ovulating to one of determining which women were likely to be capable of conceiving children--the problem of determining a woman's reproductive value or fertility (Buss, 2012). Thus, ancestral men evolved adaptations sensitive to observable qualities of a woman that correlated with underlying, future, reproductive potential (Buss, 2012; Symons, 1979; Symons, 1995). Evolved selection fashioned preferences in men for those observable qualities that pointed to female's overall health and reproductive capability. Eventually these qualities became incorporated into judgments of beauty, influencing the mating strategies of men. As per human self-domestication, females who displayed such qualities would likely be favored in the human group, improving not only a female's chances for personal survival, through adult/parent attention and access to life dependent resources, but for reproductive success as well. That is, the female possessing attractive qualities, leading in all likelihood to preferential treatment, would more likely survive long enough to eventually mate and produce viable offspring. The more the female embodied qualities signaling good health, and thus, reproductive capability, the more likely potential male suitors would have sought her out. Over the course of evolution, these qualities likely became the embodiment of an aesthetic of beauty/attractiveness. Further, the observable signs of beauty eventually became woven into a culture's notions of the beautiful, notions based in part on the reproductive potential of the female and a female's desirability; the latter as demonstrated by male mate choice in accordance with the traits associated with a female's reproductive value noted above.
Bowlby and Attachment Theory
According to attachment theory, as articulated by Bowlby (1969), every infant is endowed with certain behavioral and physical features that draw the attention of its caretakers. Bowlby (1969), in his study of infant- caretaker attachment, has advanced an ethological theory of attachment that emphasizes evolved attachment behaviors--gestures and signals, which promote and maintain proximity to caretakers. Bowlby was inspired by zoologist Konrad Lorenz's study of imprinting in baby geese (1952) which drew the former's attention to the critical period, or optimal time frame, within which human infants become bonded. It is the infant's attachment behaviors that promote bonding, the latter having survival value for the dependent members within the human community.
Behaviors that enter into the infant-mother bonding process, Bowlby (1969) labeled, 'attachment behaviors', and these include: crying (as a distress call to obtain the parent's attention) the baby's smile, babbling, grasping, gazing, clinging, and sucking. Also, the large eyes, round face, small nose and chin, chubby cheeks, all add to the aforementioned attachment behaviors and constitute evolved 'cute' facial features to which parents and adults respond positively (Eibl-Eibesfeldt, 1972). Further, the persistence of juvenile traits into adulthood has been found to not only readily elicit helping behavior from others towards those adults who display juvenile traits, known in ethological circles as neoteny (Keating et al. 2003; Petri & Govern, 2012), but general admiration is conferred by the human community of neoteny-inspired traits toward adults (Kandel, 2012; Sternglanz et al. 1977) and children who possess such features.
As we can see, helping behavior, and the associated attention that is given to infants, can also be directed toward adults who possess these advantageous, juvenile features. A clue to the influence that traits have on our response to organisms that possess certain physical and behavioral features, and to be discussed at length later in this paper, is shown by research on the domestication of the silver fox (Belyaev, 1969; Trut, 1999). In the course of selective breeding of the silver fox, an initiative undertaken by Belyaev, it was demonstrated that the character of the wild fox over the course of several generations gave way to increasing amenability to domestication, or tamability; that is, a reduction in the wild nature of this animal (e.g., aggression and fear) (Belyaev, 1969; Trut, 1999) and the emergence of behavioral features that make this animal more social in its relation to humans. Tamability was shown by reduced aggression toward humans, including: "not [being] afraid of people ... an active positive reaction to human contact.... seek[ing] contact with familiar persons.lick [ing] their hands and faces ... [and] at the sight of even a strange person, they try to attract attention with whining, wagging tails" (Belyaev, 1978, pp. 302-303). In follow-up research on Belyaev's (1969; 1978) work, Trut (1999), confirming the former's results, found the same "eagerness to establish human contact, whimpering to attract attention and sniffing and licking experimenters like dogs," among the domesticated foxes that comprised her research group (Trut, 1999, p.163). Gradually, over the course of many generations, however, it wasn't just the foxes' behavior that changed; the foxes looked different. This combination, then, of behavioral changes coupled with physical ones in the case of domestication of the silver fox, may have a bearing on how we may view the evolution of human infant features that Bowlby (1969) had reported. In the case of the silver fox, it was noted that within 10 generations, white patches started to appear on their fur. A few generations later, their ears became floppier. Eventually the males' skulls shrank and began to look more like those of females (Barras, 2018; Belyaev, 1969; Trut, 1999). The research on fox domestication suggests that perhaps a similar process, which we may call human self-domestication, might have taken place over the course of our own evolution (Barras, 2018; Cieri et al. 2014; Wilkins et al. 2014), leading to the desirable behavioral signals and physical features among human infants that Bowlby noted in his attachment research. It might be added, that when confronted with the observable evolved qualities displayed by the human infant, these qualities act to solicit attention, protection, and nurturance from adults to which infant care has been placed. It is reasonable to suppose from the foregoing that just as a selection pressure for tamability through domestication of the silver fox resulted over the generations to changes in physical and behavioral qualities altering the wild fox into a more human-friendly creature, a similar selection pressure, unique to our species, might also have been at work over the course of our evolution, bringing about the very physical and behavioral features to which Bowlby and others (Ebil-Eibesfeldt, 1970; Ebil-Eibesfeldt, 1989) have noted in the human infant. The babbling, cooing, gazing, and reflex smile that Bowlby (1969) noted among infants may be the human counterpart of the domesticated foxes' 'whining and whimpering,' as the latter seek the attention of their handlers. In addition, Trut (1999) observed on several occasions that the domesticated foxes snarled fiercely at one another as they sought and competed for the favor of their human handlers. This rivalry for the favor of the handler has its counterpart on the human level in the oft reported observation by parents of the conflict among siblings as the latter compete with one another for parental attention, resources and approbation (Buckley, 2005; Buss, 2012). Thus, in taking into account the foregoing discussion in the present section, I suggest that the silver fox domestication studies and Bowlby's (1969) work with human infants point to the value and function of certain evolved physical and behavioral features in both non-human animals and humans, and the bearing that these evolved features have on our respective responses to our charges. The proliferation of breeds among dogs, for example, show just how much we regard certain characteristics that we intentionally and selectively breed in these animals, shaping an aesthetic of appreciation that has become institutionalized as the 'dog show.' And in the case of humans, we have always admired certain physical and behavioral qualities, having universal representation among infants and appeal among adults and, figuring into the latter's judgments of what constitutes cute, desirable and beautiful.
Overall, the attachment behaviors and physical features of the human infant, and the pattern of physical and behavioral features of the domesticated fox, respectively, point to a collection of evolved features for each species that influence the attachment patterns established in relation to caretakers, whether parents in the case of the human infant, or handlers in the case of the silver fox. In the context of mother-infant interaction, Kagan (1971) notes that the "socially attractive child smiles, babbles frequently ... becomes responsive (laughing and cooing) when an adult talks to him, tickles him, or picks him up" (p. 37). Infants who behave in the aforementioned manner are more likely to attract adult attention, receiving the benefits that arise out of positive and sustained interaction with caretakers. And thus, Kagan continues, "the responsive baby.. .becomes even more responsive as a result of increasingly frequent interaction with others" (p. 37), garnishing for itself the social stimulation that being responsive to others brings. In combination with the evolved features that Bowlby (1969) noted, the responsive child participates in establishing the mother-infant bond as well as providing for itself the necessary stimulation that is essential to its own cognitive, social and emotional development.
The behavioral signals and physical features displayed by the infant, act to solicit attention, protection and nurturance from adults, all of which are essential to infant survival. Taken together, these infant characteristics, according to Bowlby (1969), are innate; they have a common pattern in almost all members of the species (i.e., are universally represented) and have adaptive value for the species by promoting the survival of its younger, dependent members. In other words, these features have evolved, are crucial for personal survival, and are broadly represented within our species. Similarly, the qualities that we associate as constituting notions of beauty have also evolved and come to influence our estimation of what is attractive. It appears then, both in the case of infants and the reproductively capable female, the more one possesses certain preferred, attractive-based features, the more likely one is regarded as attractive, desirable, and beautiful. Beauty has adaptive value in terms of the care one receives, starting in infancy, and how one is regarded and sought after in terms of male mate choice when a female reaches reproductive maturity.
Aesthetics and Evolution
Taking into account the results reported by Ford & Beach (1951) on attractiveness, it is conceivable that humans evolved an aesthetic of the beautiful, attractive, desirable, which is grounded in Darwinian natural selection. Those that possess physical features considered attractive are more likely to be included and favored in a group and thus have improved chances of survival, eventually reproducing and passing their favored characteristics into the next generation. And it is not just physical features that are favored; behavioral features, as reported in Bowlby's attachment research, are considered both adaptive and desirable. For example, the research of Cieri et al. (2014) on the role of social tolerance and sociability in humans, shows that these aforementioned behavioral characteristics are a necessary prerequisite to life in high-density populations. "Humans", according to Cieri et al. (2014), "are notable for their high levels of social tolerance and their remarkable capacity for prosocial helping and cooperation" (p. 419); behavioral patterns which have arisen from a selection pressure throughout our evolution. These behavioral patterns, as evolved, inherent human dispositions, through the mechanisms of natural selection, maturation and socialization, are encouraged from birth and integral to successful adaptation within the human group. Thus, the evolved nature of the behavioral patterns to which Cieri et al. (2014) make reference, combined with the earliest manifestation of infants' attachment behaviors as outlined by Bowlby (1969), along with the evolved qualities associated with reproductive value that influence mate selection, may be accommodated within a Darwinian model of evolution by natural selection and intentional human self-domestication.
Like Bowlby, Cieri et al. (2014) emphasize the evolution of those features, social tolerance and cooperation, which are essential to individual and collective survival. It may be that throughout our evolution, we have favored certain physical and behavioral attributes and have not left their promotion and representation within the human group to the mechanism of natural selection alone. We may have, as we have done over the past 30,000 years of animal and plant domestication, engaged in our own self-domestication, holding up certain physical and behavioral attributes as not only adaptive but, from the standpoint of aesthetics, attractive as well.
In this light, how might domestication fit into this evolution of what is considered beautiful (and behaviorally preferable)? Have desirable features been cultivated in a process of domestication through natural selection? Have we as humans intentionally self-domesticated certain physical attributes that we now hold as the hallmarks of beauty? Even during the early stages of infancy, newborns show a preference when looking at photos and simplified drawings of faces with features arranged naturally (upright) rather than unnaturally (upside down or sideways) (Berk, 2012). Newborns prefer (i.e., fixate longer at) photos of faces with eyes open and direct gaze (Fantz, 1961; Farroni et al. 2002; Turati, et al. 2006). Similarly, Slater et al. (2000) noted that there is the tendency among infants to look longer at faces judged by adults as attractive--a preference that may be the origin of the widespread social bias favoring physically attractive people that is already in evidence at a very young and tender age.
It appears on the basis of the foregoing, at the very start of life, infants have a built-in bias towards faces that embody certain features similar to the facial preferences adult's judge as attractive. For infants, the preference they show for certain facial features cannot be attributed to the bias of their parents or community, but rather to a built-in biological bias that has been the product of evolution rather than culture.
Darwin and Domestication
More than 150 years ago, Charles Darwin noticed something peculiar about domesticated mammals. In his encyclopedic investigation of domesticated species, The Varieties of Plants and Animals under Domestication (1868), Darwin noted an intriguing phenomenon. From his survey of animal breeding work, he found that domesticated mammals in general exhibit a suite of behavioral, physiological and morphological traits not observed in their wild forebears (Wilkins et al., 2014). Today, following Darwin's early work on domestication, modern biologists, Belyaev (1969; 1978), Trut (1999), Cieri et al. (2014), Wilkins et al. (2014) have noted that: the full set of characteristics to which Darwin earlier drew attention include; increased docility and tameness, coat color changes, reductions in tooth size, changes in craniofacial morphology, alterations in ear (e.g., floppy ears) and tail form (e.g., curled tails), more frequent and non-seasonal estrus cycles, alterations in adrenocorticotropic hormone levels, changed concentrations of several neurotransmitters, prolongations in juvenile behavior and reduction in total brain size and of particular brain regions. This general combination of traits in domesticated mammals is now known as the, "domestication syndrome" (DS) (Wilkins et al. 2014, p. 796).
An oft cited study of the phenomenon of animal domestication is Belyaev's selective breeding experiments with Siberian silver foxes (Belyaev, 1969). The protocol for experimental domestication of the foxes involved intensive selective breeding for increasing degrees of docility and tameness by selecting the tamest kits at each stage and then breeding only those. At each generation, the foxes were examined for morphological and behavioral changes. The full suite of traits of the DS noted in Belyaev's domestication research, has also been reported by subsequent researchers (Popova, 2004; Trut, 1999; Wilkins et al. 2014).
After more than 50 years of selective breeding work, and following in the footsteps of Belyaev's (1969; 1978) earlier research, Trut (1999; Trut, 2001) confirmed the results of Belyaev's selective breeding studies with foxes and was able to report that the suite of traits that comprise the DS displayed by her experimental animals were also accompanied by behavioral attributes normally associated with domestic dogs. The tame strain of foxes showed less aggression toward humans, a greater propensity as adults to play with humans, increased sensitivity to human communicative gestures, and the use of juvenile vocalizations by adults. In classifying the degree of tameness in her series of selective breeding experiments, Trut (1999) noted the following when assigning the foxes to one of three domestication classes. "The least domesticated foxes," she reports, "those that flee from the experimenters or bite when stroked or handled, are assigned to Class III ... Foxes in Class II let themselves be petted and handled but show no emotionally friendly response to experimenters. Foxes in Class I are friendly toward experimenters, wagging their tails ... whining" (p. 163). Trut introduced another class of domesticated foxes that she added to the three classes noted above. She called members of this group, Class IE; the "domesticated elite." Class IE foxes were "eager to establish human contact, whimpering to attract attention and sniffing and licking experimenters like dogs" (Trut, 1999, p. 163).
Overall, Belyaev's early work on selective breeding has given rise to a catalogue of traits which have received corroboration from a number of researchers in the field of domestication studies (e.g., Cieri et al. 2014; Trut 1999; Trut et al. 2009; Wilkins et al. 2014). Many species carry aspects of the DS, including our own and this has led evolutionary biologists to consider the possibility that modern humans might be a domestic version of our extinct relatives and ancestors (Barras, 2018; Cieri et al. 2014; Wilkins et al. 2014).
In the case of animal domestication, certain traits are intentionally encouraged through genetic engineering and over successive generations a selection pressure makes for desired features becoming more prevalent in the new breed. Might there be a relationship between human domestication with its concomitant changes in our physical and psychological makeup on the one hand, and a resultant aesthetic of the beautiful on the other? The more domesticated we become, the more likely we would display those psychophysical features considered desirable and transmit these benefits to our offspring. Ultimately then, over the course of our own evolution, a selection pressure has been placed on certain traits becoming the embodiment of what qualifies as the beautiful, or at the very least, preferable and adaptive. As noted earlier in this paper, the reproductive value of the human female that can be discerned by the male requires not only the evolution of female qualities signaling child bearing potential, but an evolved sensitivity on the part of the male to take note of these qualities and thus, female reproductive capability influencing male mate selection and this appears to be correlated with those evolved qualities of the female that enter into judgments of beauty.
Art and the Beautiful
In his discussion of a 'beholders emotional response to art,' notably the response to female portraiture, Kandel (2012) says, "certain ... features are universally considered attractive in the female face: arched eyebrows, large eyes, small nose, full lips, narrow face, and small chin" (p. 380), to name a few characteristics that constitute the aesthetic of beauty. Having a particular interest in the art of the fin de siecle Austrian artist, Gustav Klimt (1862-1918), Kandel (2012) goes on to say that the aforementioned features cited above are "ubiquitous in Klimt's oeuvre" (p. 380).
Another facial feature to which Kandel draws our attention is symmetry. Good symmetry indicates good genes and the "degree of symmetry in a person's face may. indicate how capable that person's genome is of resisting disease and maintaining normal development in the face of challenges" (Kandel, 2012, p. 379). Thus, symmetry, at least as it is expressed in faces, is beautiful not just for strictly formal reasons but for what it communicates about the health of a potential mate and the mate's offspring.
Those adopting a Darwinian model of mate selection (e.g., Buss, 2012; Gangestead et al. 1994; Langlois & Roggman, 1990; Petri & Govern, 2013; Symonds, 1995) are in agreement that both sexes find body symmetry (especially facial symmetry) attractive because it indicates good health in a potential mate. Further support for Kandel's observations reveal that men find young women with long hair, clear skin, full lips, smaller, rounded chins attractive because these characteristics indicate health, high fertility, and youthfulness, and thus a longer period during which the woman can conceive children (Ford & Beach, 1951; Petri & Govern, 2013; Symons, 1995). Thus, irrespective of cultural conventions regarding what constitutes the beautiful, it appears that certain features in the female are identified as more desirable and beautiful, and the research results of Ford & Beach (1951), Symons (1979), Cunningham et al. (1995), Buss (2008), Buss (2012) and Petri & Govern (2013) provide support for the consensus among different cultural groups as to what constitutes attractiveness. Furthermore, the importance of physical characteristics of men that influence female mate choice has also been noted. The evolutionary psychologist, David Buss (2012) reports: "Women prefer men who are relatively tall, athletic, muscular, and display a V-shaped torso, with shoulders broader than hips--signals that indicate a man's ability to protect a woman and her children" (p. 120), and this preference among women has been noted by others researching the latter's preference in the male physique (Dixon et al. 2003; Harrison et al. 2009).
Thus, within the context of a Darwinian model of preference for those characteristics considered desirable for women and men, it is clear that in the realm of human domestication, certain features have evolved lending support to an evolutionary approach to the biology of aesthetics. Along with the domestication of a broad range of physical and behavioral characteristics, we have over the eons placed a selection pressure on those features that define what we mean by the beautiful.
In a recent article in New Scientist, entitled Survival of the Tamest, Barras (2018) says our ancestors not only domesticated dozens of animal species but also engaged in domestication of our own species. One major insight into what happens when a species is domesticated comes from experimental genetic research by Dmitry Belyaev (1969) noted above. Over the course of several generations of selective breeding, Belyaev reports that the foxes behaved more like pets; i.e., the foxes became tamer. The tame foxes not only behaved differently from their wild counterparts, they also looked different, suggesting that the behavior and physical changes due to Belyaev's breeding program were more or less occurring in tandem. In addition to behavioral changes, physical differences between the wild and the selectively bred tamer foxes emerged. The bred foxes had white patches on their fur, their ears became floppier and the males' skulls shrank and began to look more like those of the females (Barras, 2018; Belyaev, 1969; Trut, 1999).
In subsequent studies on domestication, Popova (2004) and Cieri et al. 2014) found that foxes selectively bred showed the following features: "decreased sexual dimorphism in canine size, coat depigmentation and piebald coloration, reduced cranial capacity, feminized craniofacial skeletons in the case of the male foxes, with later generations of male foxes possessing skulls significantly shorter and wider (and more like female foxes) than the wild type" (Cieri et al. 2014, p. 422). Craniofacial feminization, to be discussed later in this paper, has also been found to be the case in human males over the course of evolutionary time by researchers in the fields of biology and physical anthropology ( Cieri et al. 2014; Wilkins et al. 2014). Collectively, the aforementioned changes reported by Popova are part of the domestication syndrome noted by researchers in the field of domestication studies (Belyaev, 1969; 1978; Cieri et al. 2014; Trut, 1999; Trut, 2004; Wilkins et al. 2014).
As for our own species, we may also display aspects of the domestication syndrome. We too have smaller teeth, relatively short faces and no prominent brow ridges. Our relatively large brains are smaller than those of our Neanderthal cousins (Barras, 2018) and it has been suggested that the reduction in brain size in modern humans is associated with "reductions in particular components of the forebrain, such as the amygdala of the limbic system (Wilkins et al. 2014). According to Cieri et al. (2014), changes in human craniofacial morphology reflect reductions in androgen activity leading to lower levels of circulating testosterone.
On the basis of the foregoing, the question arises: how is it that tameness is linked with the suite of physical and behavioral traits that form the domestication syndrome?
Neural Crest Hypothesis
Wilkins et al. (2014) pointed out that the one thing that unites the various parts of the body influenced by mammalian domestication is deficits in a tiny collection of stem cells during embryonic development. This cluster of cells is called the neural crest. Under normal developmental circumstances, as the embryo develops in the uterus, and eventually forms a fetus, the cells of the neural crest are sent around the body to form different tissues, including ear cartilage, the dentin that makes teeth, and melanocyte cells producing skin pigments. On the physiological level, the neural crest cells give rise to the development of the adrenal glands, which play a key role in fear and stress. During the initial stages of domestication of animals, the selection of certain characteristics to be promoted during selective breeding led our ancestors to select individuals that were less fearful of them, and less aggressive towards them. That made them easier to breed in captivity. Unwittingly, the tamers were selecting animals that had smaller, less active adrenal glands, a feature linked to domestication through less active neural crest cells. One outcome of less active neural crest cells is a reduction in adrenal gland function leading to a lowering of the physiological reaction to stress. In lowering the stress reaction, and reducing fearful reactivity, domesticates have a longer 'socialization window' within which to become bonded to their handlers. Neural crest deficiencies slow down the development of the physiological stress reaction by increasing the duration of immaturity of the system. Under normal captive rearing conditions domesticated animals are exposed to repeated interactions with human caretakers before the full physiological fear response is possible (Trut et al. 2004; Wilkins et al. 2014). Early human exposure means that caretakers are already perceptually recognized as low-threat stimuli by the time the physiological stress reaction matures, and thus humans do not initiate the fear response nor are they by virtue of domestication seen as a threat. A combination of neural crest deficiencies and experiential opportunities to interact with handlers makes for a tamer animal.
Trut (1999) noted that with increasing domestication, foxes displayed a delayed fear response. A delayed fear response gives more time for the animal to adapt to, and become incorporated into, a human social environment. Thus, genes with links to the neural crest should all change as a result of domestication (Wilkins et al. 2014), in keeping with the neural crest hypothesis. In looking at genetic differences between modern humans and Neanderthals, for example, the resulting variations through the process of natural selection that caused our species to diverge from our Neanderthal forebears were variations linked to the neural crest (Barras, 2018). Our own domestication, as is the case in animal domestication, it is hypothesized, resulted from neural crest cell deficiencies (Barras, 2018; Wilkins et al. 2014).
Thus, some of the genetic differences that distinguish us from Neanderthals are the same as those that distinguish dogs from wolves and European cattle from European bison and thus early in human evolution our species underwent the same sort of domestication as these other animals did. Unlike most species that underwent deliberate domestication by us, the question arises: who or what tamed us?
In response to the aforementioned question, we can say that over the course of our own evolution we placed a selection pressure on ourselves that encouraged the evolution of friendlier and cooperative traits. In doing so, we have self-domesticated (Barras, 2018). How did this come about? The objects archaeologists have found, for example, jewelry, musical instruments and other cultural artifacts became common within the past 100,000 years, 200,000 years after Homo sapiens first appeared. The question arises: Why was there this delay in our cultural development? Steven Churchill, an evolutionary anthropologist (cited in Barras, 2018) suggests that this delay might have been linked to an "intense pulse of human self-domestication 100,000 years ago" (p. 31). Our species had the capacity to innovate but the social networks necessary for ideas and other innovations to spread were not available. Why? We were too hostile and aggressive to include others, i.e., strangers, into our tribal societies. Good ideas and knowledge lived and died in the family group. The cross-fertilization of ideas and the creative efforts coming from diverse quarters was not possible in a xenophobic environment. However, as population densities began to rise, it might have been a good idea to include others, share information and technologies and thus humans experienced a selection pressure to be more friendly and welcoming of others (Barras, 2018; Cieri et al. 2014).
Cieri et al. (2014) have argued modern behaviors associated with technological innovation, such as making art and developing rapid cultural exchange, came at the same time that we developed a more cooperative temperament by dialing back aggression with lower testosterone levels. "Elevated levels of circulating testosterone," says Cieri et al. (2014) "beginning at puberty ... in males ... tend to predominantly affect facial elongation and brow ridge development" (p. 423). In addition, Cieri et al. (2014) propose that "temporal changes in human 'craniofacial feminization' reflect reductions in androgen reactivity...which in turn reflects the evolution of enhanced social tolerance since the Middle Pleistocene" (p.419). Thus, a drop in male hormone levels over the course of human domestication evolution resulted in a blooming of society with gentler personalities, temperament, reduced aggression and, less ferocious features. According to Barras (2018), "brow ridges and long, powerfully built faces faded away to leave our species looking more feminine, just like Belyaev's foxes" (p. 31, emphasis added). These physical and behavioral changes serve as overt signals that you are not going to be aggressive, and with reduced aggression and a more welcoming disposition toward strangers a sharing of ideas, technologies and artifacts that have been an advantage to the continued survival and growth of our species. Thus, the feminine aspect, in domesticated animals and humans, in both appearance and manner, evolved as a result of a selection pressure that promoted less aggressive appearance and less aggressive behavior. In humans, an ethic of social tolerance and cooperation developed. These more desirable domesticated physical attributes and behavioral dispositions have resonated over the course of our own evolution, encouraging us to prize certain attributes, especially those embodied in women and as worthy of the designation, 'beautiful.'
Femininity and the Beautiful
In his survey of the 'history of beauty,' Eco (2004) chose a reproduction of a painting by the Italian artist Agnolo Bronzino, entitled Portrait of Elenora of Toledo, c. 1545, to adorn the cover of his book. In many respects, the woman in the portrait embodies features of what constitutes the 'beautiful' to which Kandel (2012) and others draw our attention. These include the arched eyebrows, large eyes, small nose, full lips, narrow face, and small chin (e.g., Godinho et al. 2018). Additionally, arched eyebrow movements, in both women and men, allow us to express complex emotions as well as perceive the emotions of others. Our "mobile eyebrows ... play a key role in social signaling and communication" (Godinho et al. 2018, p. 1). A rapid 'eyebrow flick' also serves as a greeting signal of recognition, as an appeasement gesture; it is a feature that facilitates social interaction and is one we also admire (Eibl-eibesfeldt, 1972; Kandel, 2012).
According to Kandel (2012), the aforementioned facial features "are universally considered attractive in the female face" (p. 380). In Eco's gorgeously illustrated book, the features of female beauty that Kandel says are universal indications of attractiveness, appear again and again in the artistic renditions of the female in art. For example, Eco reproduces Leonardo da Vinci's La Belle Ferroniere, 1490-1495, (Eco, 2004, p. 203) and his Lady with an Ermine, 1485-1490 (Eco, 2004, p. 192). In these two portraits by Leonardo, we see the aforementioned features of attractiveness in the portrait of the female sitters. And later, in the history of art, in George Romney's Lady Hamilton as Circe, painted c. 1782 (Eco, 2004, p. 265), we note the arched eyebrows, large eyes, small nose and mouth, round face and blushed cheeks of the female sitter, this painting having been executed some three centuries after da Vinci's La Belle Ferroniere and Lady with an Ermine. Even as far back in the sculpture of Nefertiti, c. 1340 (Eco, 2004, p. 34), we see features of the beautiful expressed in Nefertiti that coincide with Kandel's (2012) catalogue of features, thus reinforcing the idea that there are universal features that have come to influence our judgment of what constitutes the beautiful.
The pervasiveness of universally shared features that bear upon judgments of the beautiful, or at the very least attractiveness in females, can be seen in artistic renditions in males as well. For example, in Albrecht Durer's, Self-Portrait in Fur, 1500 (Eco, 2004, p. 219), we note the following features: arched eyebrows, small, aquiline nose, small mouth, high cheek bones, large eyes, prominent, smooth forehead, delicate jaw line and chin, all of which reveal the incorporation of the feminine into the portrait of this handsome male. Moving ahead some four centuries to the 20th century, we see in the photos of Cary Grant, James Dean, and Marcello Mastroianni (Eco, 2004, p. 424), for example, an ensemble of softer and agreeable features representing the feminine in the features of these handsome men. And, several studies (Penton-Voak et al. 2004; Perrett et al. 1998; Rhodes et al. 2000; Rhodes et al. 2001b) have reported that feminized male faces are preferred over masculinized male faces (e.g. thick brows, thin lips, square chins, and small eyes are least preferred). Perrett et al. (1998), suggesting that this preference may reflect the perception of more positive personality traits; less dominant, warmer, more honest and cooperative, and more likely to be a good parent, in less masculine faces. Perrett et al. (1998) results coincide with the work of Cieri et al. (2014) on craniofacial feminization in human males; both sets of studies demonstrating that feminine features are evolved, domesticated features, to which both natural selection and intentional human self-domestication have contributed.
Linking back to the phenomenon of human self-domestication, the human male, across eons, has exhibited softer physical features and this constitutes a radical departure from the prominent brow ridge, large skull and face, extended and powerful jaw line of modern males' Neolithic forebears. The ferocious appearance and manners of human males' forebears, have given way to an assortment of physical (e.g., craniofacial feminization) and behavioral attributes (e.g., increased social tolerance) that have collectively contributed to our success as a species (Cieri, et al. 2014). Yet, to be truly tame, to be civilized, is to be feminine (e.g., cooperative, empathic). We show our appreciation and admiration of the feminine in our portrayal of women in art throughout the ages; upholding 'woman' as the embodiment of the beautiful, the desirable, the admirable, both in appearance and manner. Through continued self-domestication, we as a species became tamer and it is tameness that has contributed to our individual and collective survival. With tameness has evolved cooperation, empathy, altruism, and tolerance; the ingredients necessary for us to flourish as a species. And 'woman' may serve as the model for the aforementioned attributes, embodying what we mean, including and beyond the physical, by 'the beautiful'.
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The author would like to thank Eric Oosenbrug, PhD candidate in the history of psychology at York University, Toronto, Canada, for his helpful editorial comments.
Frank J. Marchese
York University, Canada
Author info: Correspondence should be sent to: Dr. Frank Marchese, York University, Toronto, Ontario, Canada
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|Author:||Marchese, Frank J.|
|Publication:||North American Journal of Psychology|
|Date:||Dec 1, 2018|
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