Evolutionary Psychology - Gender Differentiation

Evolutionary Psychology - Gender Differentiation

PSYCHOLOGICAL EVOLUTION and GENDER-BASED DIFFERENTIATION

Gender-based differentiation is nearly universal among all sexually-reproducing biological organisms. Generally, males and females of every known species exhibit characteristic differences; furthermore, in most cases, these differences are consistent across the biological spectrum, with relatively few exceptions. Exceptions do exist, such as where the female is larger and more dominant; in several known species, only the male broods over fertilized eggs. But similar frequencies of exception also exist with regard to most non-gender-specific behaviors and they merely represent an alternate evolutionary solution to a problem rather than a contradiction of general observations of extreme consistency of gender-specific behavioral (Barash & Lipton 2001).

Generally, the most common gender-based differences relate to relative body size, dominance, physical aggression, and to equally distinctive courtship, mating, and parenting behaviors, which parallel the same differences in very different and evolutionarily-distant species (Zimbardo 2005). The more we learn about the evolution of species, the more similarities we find in organic structures, neurological architecture and processes, hormonal regulation, and external manifestations of those organic similarities between human beings and thousands of different species of so-called "animals."

In fact, the evidence is so persuasive and complete that the fairest possible distinction we should make may be between "non-human" animals and "human" animals. Fair, because we differ from the rest of the animal kingdom only in degree and hardly in kind. Since the development of DNA technology and forensic testing techniques, we have been able to pinpoint some of the precise genes that differentiate human behavior from our closest Simian relatives. The same techniques allow us to peer backward in evolutionary time to the more general differentiation of mammalian and reptilian behavior. Nevertheless, the sheer complexity of human social relationships, if not the uniqueness of our physiology, does correspond to some of the most interesting observations of gender-based evolutionary differences in species.

General Behavior:

From earliest childhood, human males and females exhibit differential behavior patterns: boys tend to socialize in the context of an external focus, such as a physical objects or within group activities; girls tend to focus more directly on each other. Girls are much more likely to form close relationships with another specific individual, and they devote more time, in comparison to boys, to talking about themselves, other people, and to expressing their feelings verbally (Zimbardo 2005).

Females of all ages tend to talk more about people and feelings, whereas males focus more on discussing things, like sports, cars, politics, and business interests.

Evolutionary theorists suggest that this difference relates all the way back to our primitive prehistoric early humanoid ancestors, whose males evolved behavioral tendencies conducive to the requirements of group cooperation, planning, and in the execution of physical tasks like hunting and fending off physical threats (Margulis & Sagan 1999). Females evolved behavioral tendencies conducive to establishing necessary family and extended family social bonding and, especially, behavioral tendencies conducive to communicating with and understanding the needs of infants. In our distant evolutionary past, females evolved the instinctive ability to establish and maintain social relationships with other females and the perceptual ability to recognize the needs of their infants. Females who did were simply more successful at reproducing and raising an infant than those who did not evolve those behavioral characteristics (Margulis & Sagan 1999).

Similarly, human males mirror the general physiology and behavioral differences observed in other hominid species between the genders: they tend to grow larger, stronger, and more physically robust; they are more likely to pursue the excitement and challenge of novelty or even dangerous risks; they are more dominant as well as more inclined toward displaying it; they are much more territorial and prone to violent confrontations; and in the modern extreme, they are also more likely to become criminals (Macionis 2002). Finally, as will be discussed in greater detail in the subsequent section, like males of most other species, human males also devote much more energy and resources to continual status displays, which stem from the same evolved urges whether their ultimate social expression involves eating first and wildly tearing up branches or talking loudly in public and driving expensive vehicles (Branden 1999).

The Mating Urge and Parenting:

As with other components of biologically-evolved human behavior, the mating urge is expressed very differently in most species, although notable exceptions and role- reversals have been well documented. In humans, the principle differences relate to the fact that males have a genetic reason to pursue multiple sexual partners throughout their reproductive lives, whereas human females benefit from selecting male partners with the best genes, and from their ability to maintain a partner's interest at least long enough to raise infants supported by resources and protection provided by her partner (Ackerman 1995).

Just as our earliest female ancestors must have been drawn to more dominant males who commanded both control over others and access to resources, modern females are correspondingly drawn to powerful men, except that in contemporary society, those traits are exhibited by powerful careers and the accumulation (and display) of monetary worth. Both men and women are drawn to physical symmetry in bone structure and size proportionality, sometimes even with respect to differences too small to be perceived consciously but measurable with precision equipment (Zuk 2002).

Nevertheless, symmetry seems to be valued more highly among females as a criterion for potential selection of male candidates for partnership (Margulis & Sagan 1999), possibly as a simple function of the fact that they must consider potential genetic investment more judiciously and critically than males.

Women have evolved two strategies in that regard: identifying behavioral clues that a given potential partner possesses some of the traits consistent with higher incidence of compassion, loyalty, and nurturance; or, in the alternative, by coaxing some of those behaviors out of their eventual choice of partner (Ackerman 1995). In all likelihood, human females probably employ both strategies in combination as well as according to need. In some respects, the very traits of males that were most valuable to humanoid females actually conflict with the traits consistent with empathy, fidelity, and long-term resource dedication. Highly dominant, physically aggressive, and protective males are much less likely to exhibit higher degrees of the behaviors necessary to ensure long-term devotion than less dominant, aggressive, or protective males (Barash & Lipton 2001).

Reciprocally, the males best-suited to long-term devotion and the prehistoric precursors of so-called family values exhibited fewer of the physical characteristics and behavioral tendencies of their more aggressive and dominant counterparts.

Males, on the other hand, benefit much more, (in evolutionary terms, that is), from investing as few resources in any particular female as necessary to impregnate her; his job is finished at that point. In "cold" evolutionary terms, he may actually have a better statistical chance of propagating his genes successfully to subsequent generations simply by impregnating as many females as possible, even if relatively few manage to deliver a healthy infant and protect and feed it to full development without his continued involvement (Barash & Lipton 2001). In its modern behavioral incarnation, male mating behavior often consists of very strong parallels to male mating behavior observed in the rest of the natural world. For example, the human male may not maintain large harems the way male lions do, but he pursues sexual liaisons with comparatively little thought into what potential every sexual partner may represent in terms of long-term qualities.

Physical attraction in general, and physical indicators of high estrogen levels (and therefore, fertility) in particular, are sufficient to provoke a man's sexual interest in a specific woman (Margulis & Sagan 1999). Women are also attracted to external indicators, (such as high testosterone and physical strength), but generally require more than mere physical attraction to develop a focused sexual interest, or sexual receptivity to male overtures. As mentioned already, many of the very external physical and behavioral male features consistent with prized genetic value often come at the expense of other desirable traits that are less characteristically male (Barash & Lipton 2001).

As a result, women have evolved so as to retain some of the physical features and behaviors associated with an infant's ability to inspire parental bonding and protection, such as a high voice, relatively small body size, and larger eyes in proportion to body size (Zuk 2002). These evolved female characteristics are designed to help facilitate a bond, particularly on his part, sufficient to guarantee his continued attention and protection throughout at least one parenting cycle. While males need not necessarily consider every sexual liaison as carefully, they have still evolved tendencies toward sexual interest in specific female traits (now) known to be consistent with fertility (Zimbardo 2005). For example, regardless of national orientation or cultural of origin, men across the world tend to exhibit a strong sexual preference for a specific hip-to-waist ratio, along with other physical features, like a clear complexion, fuller lips, and soft hair that have also recently been determined experimentally, to correspond to much higher female fertility levels (Margulis & Sagan 1999).

For that matter, according to evolutionary biologists, the phenomenon of hidden female fertility cycles evolved as a very specific adaptation to the male's roving eye.

Since males of all sexually reproducing species are naturally drawn to signs of fertility in females (Zuk 2002), they naturally express more interest in females when they ovulate, or come into heat in the vernacular applied to non-human animals. In many other species that do not rely as much on a monogamous pair bond for the survival of the fetus (Barash & Lipton 2001), females exhibit very clear external signals corresponding to their ovulation. This system is very well suited to species where a single male (or several) mate with many females, such as among lions and many mammals; in fact, it probably reduces any potential for conflict among harem females for male attention.

Human females replaced the outward signals of ovulation and fertility by evolving a suppression of any outward manifestation, precisely, to ensure that males provided for, guarded, and protected them continually rather than only that portion of the time that females were most fertile (Margulis & Sagan 1999). Furthermore, male and female primates, (including human primates), even evolved gender-specific behaviors for increasing their statistical probability for long-term genetic propagation by supplementing the genetic contribution of their mate with genetic material from other partners (Margulis & Sagan 1999). Several species of female primates and non-primates have evolved a tendency to stray from their primary pair bond on occasion. The most interesting aspect of these dalliances, is that they tend to do so very specifically when they are fertile rather than at random times. As it turns out, (Margulis & Sagan 1999) human females exhibit the very same predisposition: studies of infidelity among married females indicate that the occurrence of illicit sexual affairs spiked in relation to their ovulation.

Even more interestingly, those studies also suggested that their specific choices of partners for sexual affairs tended to emphasize both raw physical attractiveness as well as some of the very characteristics associated with male dominance and strength that, fundamentally, may be inconsistent with male traits like fidelity for which they selected their husbands (Margulis & Sagan 1999). It seems that modern human females have evolved a preference in their illicit affairs for the very male candidates whose genetic material supplements the relative deficiencies in their primary partner's. Finally in this regard, the most fascinating aspect of theses studies is that the marked coordination between female sexual affairs in marriage (and the preference for superficial traits instead of those suggesting that a man is good long-term mate potential) exists even when the woman very specifically does not wish to become pregnant from the affair (Barash & Lipton 2001). Such is the unconscious effect of biologically-evolved sexual adaptations on modern human behavior.

Human males and females display characteristic differences in their relative degrees of natural ability in communication skills and in their natural responses to infants and children as well. Whereas males tend to communicate with children primarily in the context of teaching and disciplining, females are much more attentive to the subtle needs of children for focused attention, feeding, and nurturing. Men often exhibit better navigation skills, sense of direction, and analytical ability, whereas women exhibit better social skills, linguistic, and communication skills.

Distinguishing Biology From the Contributions of the Human Socialization Process:

One complication in interpreting modern manifestations of human behavior is that the social evolution of human societies has also had a profound effect on observable human behavior, including many aspects of differential male and female characteristics (Zimbardo 2005). Recent literature (Angier 2007) emphasizes the degree to which certain components of what we consider to be "typically" male or female behavior are the result of the socialization process that begins as early as the color selection of the blankets placed over newborns in the hospital, continuing into childhood and even into our expectations of adult choices.

Disparate treatment, rather than genetic differences can also account for many directional choices, but the vast majority of evidence strongly suggests that socialization, while significant, pales in its power to determine our behavior compared to biological influences (Macionis 2002). In this regard, some of the best anecdotal evidence comes from children born with externally ambiguous genitalia, as well children born with an obvious natural predisposition toward a reversed gender identity. It is relatively common practice, for example, that in the case of children born with both male and female genitalia, physicians generally make the choice of whether or not to remove the penile structure based on its apparent degree of departure from normal development: barely formed penile tissue is simply removed and the child raised as a female, and vice- versa, in the case of better developed male genitalia (Zimbardo 2005).