Why Beautiful People Have More Daughters: From Dating, Shopping, and Praying to Going to War and Becoming a Billionaire–Two Evolutionary Psychologists Explain Why We Do What We Do (3 page)

All of our claims are fully referenced to scientific studies that provide supportive evidence. For endnotes that simply give citation information, we use the standard endnote reference numbers, for example.
¹
References that give greater information not contained in the text have reference numbers with brackets, for example.
^[2]

Evolutionary psychology is a new, emerging field. The first landmark studies in evolutionary psychology were published in the late 1980s,
¹
and the birth of modern evolutionary psychology was marked in 1992 with the publication of the tome
The Adapted Mind: Evolutionary Psychology and the Generation of Culture
,
²
which is often regarded as the bible of modern evolutionary psychology.
³
What was there before then? Before we tackle the question, “What is evolutionary psychology?” in this chapter, let's pause a moment to consider what theories and explanations were available to social scientists before its advent.

A Typical View from the Social Sciences

Most social scientists explain human behavior in a more or less typical fashion. The particular school of thought is called “the Standard Social Science Model.”
⁴
Because social scientists and their theories tend to have a lot of influence on the general public, the same view also characterizes how ordinary people account for human behavior in their everyday lives.

What exactly is the Standard Social Science Model? A set of related principles characterize its main tenets.

 

1.
Humans are exempt from biology
. Social scientists who subscribe to the Standard Social Science Model know that biology (and its branches, like zoology, ornithology, and entomology) can explain the behavior of all other species in nature. Yet they make an exception for humans as a sole species whose behavior is not explained by biological principles and theories. Human exceptionalism is the hallmark of the Standard Social Science Model. Many social scientists have averse reactions to biological explanations of human behavior.
⁵
This principle says that humans are exceptions in nature.

 

2.
Evolution stops at the neck.
⁶
Social scientists in the Standard Social Science Model tradition, who do not believe in biological influences on human behavior and cognition, nonetheless acknowledge that human anatomy has been shaped by evolution. They recognize that human body parts, such as the fingers and the toes, are the way they are because of a long evolutionary process of natural and sexual selection. However, they contend that evolution has had no effect on the contents of the human brain and the human mind. This principle says that the brain is an exception in the human body.

 

3.
Human nature is tabula rasa (a blank slate)
.
⁷
As a result of principle 2 above, social scientists in the Standard Social Science Model tradition contend that humans are born with a mind like a blank slate. Once again, they recognize that all the other species have innate natures: dogs have an innate dog nature, which makes them behave more or less the same no matter where they live or what their individual life experiences have been, and cats have an innate cat nature, which similarly makes them behave the same but different from dogs. The same goes for all species in nature—
except for humans.
Humans do not have an innate nature, as they are born with minds that are blank slates. Principle 3, like principle 1, is an example of human exceptionalism.

 

4.
Human behavior is a product almost entirely of environment and socialization.
Since, according to the Standard Social Science Model, humans have no innate human nature that guides their behavior, the contents of human nature must be written after birth. The Standard Social Science Model contends that this occurs by a lifelong process of socialization (learning via instruction, imitation, copying, etc.) by the agents of socialization (parents, other family members, teachers, other adults in society, the media). Humans become the way they are because of socialization; socialization makes them human. In particular, men and women acquire their typical male and female behavior through gender socialization. This is why another name for the Standard Social Science Model is
environmentalism.
Most social scientists believe that the environment and life experiences almost entirely shape and determine human behavior.

 

Admittedly, this is a somewhat simplified version of the Standard Social Science Model, but it is not far off the mark. Not all social scientists agree with all of the four tenets, but most would agree with most of them to a large extent (and many agree with all).
⁸
Recent surveys of introductory textbooks in sociology and psychology reveal very cursory (and often incorrect) discussions of human evolution and its effect on behavior.
⁹

The Evolutionary Psychological Perspective
^[10]

Let us now look at the basic principles of evolutionary psychology. You could not possibly miss the sharp contrast between the Standard Social Science Model and evolutionary psychology.

As we said in the introduction, evolutionary psychology is the study of human nature. While the phrase “human nature” is used in common discourse to mean something essential but otherwise undefined about being human, it has a specific meaning in evolutionary psychology. It refers to a collection of components called
evolved psychological mechanisms
or
psychological adaptations
(these two terms are roughly synonymous). Human nature is the sum of such evolved psychological mechanisms, and evolutionary psychologists aim to discover more and more such psychological adaptations in humans. What, then, is an evolved psychological mechanism or psychological adaptation?

Evolved Psychological Mechanisms: What Human Nature Is Made Of

An adaptation is a product of evolution by natural and sexual selection,
^[11]
and it allows an organism to solve particular problems.
¹²
Our body is full of adaptations. Our eye is an adaptation; it allows us to see, navigate efficiently and safely, find prey, and avoid predators. Our hand is an adaptation; it allows us to hold and manipulate objects efficiently, collect and eat food, throw objects, and use and manufacture tools. If you imagine what your life would be like without an eye or a hand, you can begin to see the range of problems that these physical adaptations solve. Problems that adaptations allow us to solve are called adaptive problems. Adaptive problems are problems of survival and reproduction. Without solving adaptive problems, we will not be able to live long or reproduce successfully.

Psychological adaptations are like these physical adaptations in our body, except they are in our brain. They allow us to solve some adaptive problems by predisposing or inclining us to think or feel in certain ways. Just like we see or manipulate objects without much conscious thought, psychological adaptations often operate behind and beneath our conscious thinking. All adaptations (physical and psychological) are also
domain-specific
; they operate and solve problems only within a narrow area of life. The eye allows us to see but not manipulate objects; the hand allows us to manipulate objects but not see them. What the eye can do, the hand cannot, and vice versa. This is true for evolved psychological mechanisms as well; they only operate and solve problems in a narrow range of life.

Our preference for sweets and fats is an example of an evolved psychological mechanism.
¹³
Throughout most of human evolutionary history, getting enough calories was a serious problem; malnutrition and starvation were common. In this environment, those who, for reasons of random genetic mutation, had a “taste” for sweets and fats, which contain higher calories, were better off physically than those who did not have such a taste. Those who had a sweet tooth therefore lived longer, led healthier lives, and produced more healthy offspring than those who did not. They in turn passed on their (genetically influenced) taste to their offspring, over many thousands of generations. In every generation, those with this taste out-reproduced those without it, generation after generation, until most of us living today have a strong preference for sweets and fats.

Male sexual jealousy is another example of an evolved psychological mechanism.
¹⁴
Because gestation in humans and most other mammalian species occurs inside the female body, males of these species (including men) can never be certain that they are the father of their mates' offspring, while females are always certain of their maternity. In other words, the possibility of unwittingly raising children who are not genetically their own exists only for men. The technical term for this is
cuckoldry
. A man is
cuckolded
when his wife has an affair with someone, has a child by the lover, but successfully passes the child off as the husband's. According to one estimate, about 13–20 percent of children in the contemporary United States and 9–17 percent in contemporary Germany are not the genetic offspring of the man whose name appears on the child's birth certificate.
¹⁵
Another study shows that about 10–14 percent of children in Mexico have legal fathers different from their genetic fathers.
¹⁶
Earlier estimates from the US, the UK, and France range around 10–30 percent of all children.
¹⁷
As anyone who's ever watched a daytime talk show knows, concerns about biological paternity are far from a remote theoretical possibility; in fact, anywhere from one out of ten to one out of three children are raised by men who are unrelated to them genetically.

In evolutionary terms, men who are cuckolded and invest their financial and emotional resources in the offspring of other men end up wasting these resources, as their genes will not be represented in the next generation. For this reason, men have a strong evolutionary reason to be sexually jealous, while women, whose maternity is always certain, do not. The same psychological mechanism of sexual jealousy often leads to men's attempts to guard their mates physically, in order to minimize the possibility of their mates' sexual contact with other men, sometimes with tragic consequences.
¹⁸

While men and women present the same frequency and intensity of their jealousy in romantic relationships,
¹⁹
there are clear sex differences in what triggers jealousy. The evidence from surveys and from physiological studies conducted in different cultures indicates that men become jealous of their mates'
sexual infidelity
with other men, underlying their reproductive concern for cuckoldry. In contrast, women become jealous of their mates'
emotional involvement
with other women, because emotional involvement often leads to diversion of their mates' resources from them and their children to their romantic rivals.
²⁰
While recent critics of evolutionary psychology have questioned these conclusions mostly on methodological grounds,
²¹
both strong evolutionary logic and a preponderance of empirical evidence support the clear sex differences in romantic jealousy described above.
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Hardwired, Not Hardheaded

Recall that evolved psychological mechanisms mostly operate behind and beneath conscious thinking. We do not consciously
choose
or
decide
to like sweets and fats. We like them but we do not know why; sweet and fatty foods just taste good to us. Similarly, we do not consciously
choose
or
decide
to feel jealous. We feel jealous under some circumstances, in response to certain predictable triggers, but we do not always know why. Evolutionary psychology contends that these evolved psychological mechanisms are behind most of our preferences, desires, and emotions, and they incline us to behave in certain ways. Evolutionary psychology explains human behavior in terms of the
interaction
between these evolved psychological mechanisms; the preferences, desires, and emotions that they produce in us;
and
the current environment in which they express themselves. This is why both biology and environment are important components of any complete explanation for human behavior, even though, for reasons we noted in the introduction, we tend to emphasize the biological factors more in this book.

Evolutionary psychology is an application of evolutionary biology to human behavior. It is characterized by the following four principles, which form very clear contrasts to the four principles of the Standard Social Science Model, which we discussed above.

 

1.
People are animals.
²³
The first and most fundamental principle of evolutionary psychology is that there is nothing special about humans. They are just like all the other animal species. Now that does
not
mean that humans are not unique; they are. But then so are all other species. If humans are not unique, they would not be a separate species. The reason why human beings are a separate species is because no other species have exactly the set of characteristics that humans do. But the same thing can be said of chimpanzees, gorillas, dogs, cats, and giraffes. Humans are unique, but no more or no less so than fruit flies. Evolutionary psychology recognizes that the same biological laws of evolution apply to humans as they do to all other species. It therefore refutes the human exceptionalism of the Standard Social Science Model. In the words of the great sociobiologist Pierre L. van den Berghe, “certainly we are unique, but we are not unique in being unique. Every species is unique and
evolved
its uniqueness in adaptation to its environment.”
²⁴