Evolutionary Psychology and Human Behavior: Wright's Moral Animal

Introduction to Evolutionary Psychology

To understand Robert Wright, it is first necessary to define evolutionary psychology, which is the foundation of Wright's theory. Evolutionary psychology contends that most, if not all, of human behavior can be understood through the interests of internal psychological mechanisms. These internal mechanisms are adaptations — products of natural selection that helped human ancestors survive and reproduce. Evolutionary psychology looks at the challenges early humans faced in their hunter-gatherer environments and the problem-solving they engaged in to meet those challenges. Based on these problem-solving adaptations, it establishes the common roots of ancestral behavior and, especially relevant to Wright's book, how these common behavioral roots are observed and acted upon today. Human behavior, just like physical traits, has passed from one generation to the next. In their brains, humans carry specific knowledge that helps them adapt to the environment. The brain is subject to natural selection just like any other organ.

As Wright explains in the introduction (9), evolutionary psychologists discern the second level of human nature: anthropologists find recurring themes in cultures, such as a need for social approval and a capacity for guilt. Psychologists explain that these themes vary from person to person — one person's desire for social approval may be low while another's is high. Genetic differences play a role, but genetic commonalities play a larger one. There is a species-wide developmental program that absorbs information from the social environment, and the brain adjusts accordingly.

Wright explains that humans are genetically shaped by evolution to replicate their genes. There is a biologically based human nature in which all organs in the body are "adaptations" or "fine products of inadvertent design" (26), which exist today because in the past they contributed to an ancestor's fitness. All these organs, as noted above, are species-typical. There may be individual differences, but on the whole, most of the genes governing one organ, such as the lung, are the same from one person to the next.

Darwin summed up natural selection as "Multiply, vary, let the strongest live and the weakest die" (24). Here, according to Wright, "strongest" does not refer only to the physically powerful, but also to other ways of adapting to the environment — such as camouflage and, in the case of this book, cleverness and other mental adaptations. The word "fitness" refers to the task of transmitting genes from generation to generation within a specific environment. Fitness is the factor that natural selection continually "seeks" to maximize and improve as it continuously redesigns the species. Fitness is what drove humans to act as they do today. The human body was shaped by hundreds of thousands of incremental advances, with each increment being the result of an accident that helped one ancestor get its genes into the next generation.

Wright then extends this concept to the brain and today's modern mind. Why, he asks, should the organ of the brain be any different from these other organs? Mental organs, which make up the mind, are species-typical as well. The hundreds of thousands of genes that affect human behavior — genes that created the brain and control neurotransmitters and other hormones — have persisted from early ancestors to the present for a reason: they drive humans to extend their genes from one generation to the next. Assuming the theory of natural selection is correct, then everything about the human mind should be understood in these terms. The fundamental ways that people feel about each other, the basic things individuals think and express to one another, are all part of the makeup of the mind because they were able to pass on genetic fitness.

Male and Female Reproductive Strategies

Wright explains that differences exist between males and females and their ultimate goals in achieving fitness. To determine what females are inclined to seek in males — and males in females — it is necessary to refer back to the ancestral environment. The behavior observed today is not based on the present environment, but on the one that existed thousands of years ago, to which early humans adapted. This ancestral environment helps explain why females are less sexually reserved than females in any other species, and why the level of reserve for females in the human species is higher than it is for males, regardless of the environment. This is based on the premise that over her lifetime, an individual female is able to produce many fewer offspring than an individual male. Such reproductive asymmetry exists much farther back in evolutionary time than early humans; it extends through the reptiles. Female snakes, for example, mate only with certain males. Females are thus inherently selective — or "precious" — because of their biological role in reproduction and the slow rate at which they can reproduce.

This choosiness by females is grounded in natural selection, because it "gives great moment to their choices," as Darwin noted (34). If females prefer to mate with a particular kind of male, those kinds will proliferate. The ornamentation of male animals — such as the lizard's inflatable throat sac — has evolved not because it aids daily survival, but because it can attract females. Similarly, a stag's horns help win in combat. Both ornamentation and combat ability are components of sexual selection.

Natural selection unconsciously ingrained in organisms both certain physical and mental traits to maximize genetic legacy. This goal implies different tendencies for males and females. Males can reproduce hundreds of times a year, but females can only reproduce once a year. For men, reproductive success is advanced by having more partners and getting more genes into the next generation. For women, however, the answer is quality, not quantity. Having a child involves a great deal of time and effort. Each child, because of genetic reproduction, is very precious.

Parental investment includes producing the egg or sperm, achieving fertilization, gestating the egg, and rearing the offspring. Females make the higher investment both before and, in most cases, after birth. The child must survive and in turn pass on its genes to the next generation. Women must therefore be very selective about the men they choose as co-producers of these children. Unconsciously, shaped by thousands of years of history, a woman "sizes up" a man and is attracted or not attracted based on natural selection. Genes leading to attractions that proved good for genetic legacies have flourished; those leading to less productive attractions did not. People's minds are designed to maximize fitness in the environment in which those minds evolved. Only the traits that propelled genes from one generation to the next should, in theory, be part of today's human nature — and these stem from the hunter-gatherer environment.

As noted by Trivers (42), quantifying the imbalance of investment between mother and father helps to better understand many phenomena: the dichotomy between male eagerness and female coyness, the intensity of sexual selection, subtle aspects of courtship and parenthood, and the dynamics of male-female bonding, fidelity, and infidelity. Such behavior, as Trivers suggested, results from a deep psychological complexity. The basic emanations of natural selection extend from the older parts of the brain all the way into the newest tissue.

References

Wright, Robert. The Moral Animal. New York: Pantheon Books, 1994.