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 (24 page)

 

So the scorecard for evolutionary psychology, as of 2007, is 3–3. Three of the six questions on Wright's 1994 list have been satisfactorily solved; the other three remain unsolved.

To this list of three remaining questions, we would like to add a few more. Here are a few other questions that currently present theoretical puzzles to evolutionary psychology.

 

7.
Why do children love their parents?

At first glance, this question may appear absurd.
Of course
children love their parents; it is only natural. But why?

If you really think about it, there is absolutely no evolutionary psychological reason why children should love and care for their parents. Some people (usually parents themselves) have suggested to us that parents will be more motivated to invest in children who love them back. But this is not true; from an evolutionary psychological perspective, parents
have to
love their children, whether the children love them back or not, in order to motivate their parental investment. And, as Daly and Wilson's work on discriminative parental solicitude shows, parents are motivated to invest not necessarily in the children who love them most, but in those who have the greatest potential to attain higher reproductive success themselves (more attractive, more intelligent, healthier children, or boys if the parents are wealthy, girls if they are poor, etc.). If parents with limited resources have two children, one an intelligent, physically attractive, and healthy child who hates them, and the other a handicapped, unattractive, and sickly child who loves them, the cold evolutionary logic dictates that the parents invest in the former, not the latter. So the children do not really have to love their parents.

This is especially true for adult children. While the parents are still young, they can potentially produce further offspring with whom the children share half their genes. So it might make sense for the children to invest in and take care of their parents, so that they can produce more siblings. But once the parents are past the reproductive age, this is no longer possible. So it makes no evolutionary psychological sense for adult children to take care of their elderly parents.

Yet the overwhelming evidence from most human societies shows that children do love their parents, and this is a theoretical puzzle for evolutionary psychology—although probably
only
for evolutionary psychology.

 

8.
Why do parents in advanced industrialized nations have so few children?

This is slightly different from question 3 above on Wright's list about why some people choose to be childless. Most people—for example, 90 percent of contemporary Americans—have children. However, despite the fact that most middle-class Americans could comfortably raise four or five children and invest sufficient resources in each of them, most parents choose to have only about two children.

In fact, there is an additional layer to this puzzle. Most Americans prefer to have a boy and a girl, rather than two boys or two girls. Parents who have two children of the same sex are more likely to have a third child than parents who have a boy and a girl.
¹⁸
Why Western parents do not have as many children as they can safely afford and invest in, and why they have a preference for a child of each sex, remains a mystery from the evolutionary psychological perspective.

 

9.
Why do people find a tan attractive? Why do men hog the remote control and typically channel surf much more than women? Why are men mostly responsible for barbecuing and carving meats while women do most of the other cooking?

These are some of the trivial observations that we and others have made that are too widespread, consistent, and strong to be coincidental or the result of cultural socialization. It is likely that there are some biological or evolutionary reasons behind such consistent observations. For example, some argue that tanning is young, single women's means to advertise their health and beauty and that this is why young, single women are more likely to get a tan than others.
¹⁹
To the best of our knowledge, no one has begun to propose explanations for any of the other puzzles.

In order for evolutionary psychology to explain such phenomena, however, we must first make sure that they are truly culturally invariant human universals (or if there are minor cultural variations, they can be explained as interactions between evolved psychological mechanisms and local ecology and environment).
²⁰
If the observations are not truly culturally universal, then it is unlikely that they have biological or evolutionary roots. The first thing evolutionary psychologists must do in order to explain widespread behavior is to establish that it is culturally universal.

This is exactly what the pioneer evolutionary psychologist David M. Buss did in the 1980s, when he conducted research in thirty-seven different cultures on all continents to ascertain that the preferences for ideal mates expressed by students at the University of Michigan are indeed widely shared by people in all human societies.
²¹
Others have followed in Buss's footsteps. One recent study was conducted in fifty-two nations, ten major world regions, six continents, and thirteen islands, and found that expressions of sexual desires (such as the desire for sexual variety) and their consequences (such as the practice of “mate poaching”—stealing someone else's mate) are more or less the same in all societies.
²²
Cultural universality is one of the hallmarks of the evolved mind.

 

We hope this quick survey of remaining theoretical puzzles in evolutionary psychology makes it abundantly clear that there are still many questions to be asked and many puzzles to be solved in modern evolutionary psychology. We both left sociology and became evolutionary psychologists in response to
one sentence
by Robert Wright in his 1994 book
The Moral Animal
: “For now, this is the state of evolutionary psychology: so much fertile terrain, so few farmers.”
²³
We became farmers and started tilling the fertile terrain. Wright's observation for evolutionary psychology is much less true now in 2007 than it was in 1994, as a large number of young and talented graduate students in psychology, anthropology, and elsewhere choose to pursue evolutionary psychology, which is probably the fastest growing academic field today.

At the 17th Annual Conference of the Human Behavior and Evolution Society (the main academic organization of evolutionary psychologists) held in Berlin in 2004, the then HBES president Bobbi S. Low remarked that the number of people who were on the program committee, which successfully planned and organized the Berlin conference in 2004, was larger than the entire group of people who originally gathered only two decades earlier to form the academic organization that later became HBES. Many attendees of these early meetings slept on the floor of Low's house when they met at the University of Michigan in the 1980s.
²⁴
Twenty years later, the 2005 HBES meetings were held in the Hyatt Regency in Austin, Texas, with nearly five hundred participants. We have a feeling that five hundred house guests would have stretched even Low's enormous hospitality.

The growth of evolutionary psychology has also been international; in addition to the United States and the United Kingdom, where scientific research in every field is most active, evolutionary psychology has a particularly and disproportionately large following in Japan and Belgium. Yet we could always use more bright minds to help us solve the remaining theoretical puzzles in evolutionary psychology. Apply within.