Evolutionary Psychology 101 by Glenn Geher PhD;

Author:Glenn Geher, PhD;
Language: eng
Format: epub
Publisher: Springer Publishing Company, Inc.
Published: 2013-04-15T00:00:00+00:00

The Oftentimes-Helpful, Churchgoing Ape

KEY TERMS

The altruism problem

Inclusive fitness

Direct versus indirect fitness

Relatedness

Reciprocal altruism

Moral emotions

Cheater detection

Competitive altruism

Sexually selected altruism

Multilevel selection and altruism

Evolutionary accounts of religion

Wilson’s idea of the “horizontal” and “vertical” dimensions of religion

In the field of evolution, there are many paradoxes—things about the nature of life that seem to fly in the face of evolutionary principles, or things about life that simply make little sense from an evolutionary perspective. Perhaps the best-known example of such a phenomenon is altruism, generally defined as the helping of another organism at a cost to oneself. Think about it. If “evolution is right,” and organisms that evolved and typify life on this planet are full of adaptations that facilitate their own reproductive success—why and how could altruism evolve?

This issue has become known as the altruism problem and, fortunately, as you’ll see, examining this problem actually led to extraordinary advances—not only in our understanding of evolutionary processes, but in our understanding of altruism as well. In other words, the altruism problem didn’t take down evolutionary theory. Rather, it bolstered evolutionary theory.

KIN-SELECTED ALTRUISM

William Hamilton, a renowned zoologist whose work in the 1960s revolutionized our understanding of evolution, was the first to make substantial headway in solving the altruism problem. At the time, Hamilton (1964) was studying several species described as the social insects. Social insects include many species of bees, wasps, ants, and other kinds of insects. The defining feature of a social insect species is the fact that individuals work together and function as something of a group organism—such as honeybees, with a hive including a queen and thousands of worker bees and drones that work in a coordinated fashion to obtain food, help build the nest, and so on. In short, the social insects seem to show extraordinary levels of altruism, including behavior that is clearly for the benefit of the hive and/or the queen—often at a cost to the individual (with many species of social insects displaying kamikaze behaviors!).

So if you’re an evolutionist and you study the social insects, you’ve got to wonder: How could these complicated and seemingly altruistic behaviors have evolved? Due to our understanding of genetics, there’s an answer—and Hamilton was the first to document this connection between genetic constellations of particular species and patterns of altruistic behaviors. Hamilton’s big insight is essentially this: The social insects have a different pattern of genetic relatedness to one another compared with other sexually reproducing species such as humans. Drones receive 100% of their genes from the queen—and workers will share 75% of their genes with one another (as opposed to the 50% of shared genes that humans share with full siblings).

So here’s the connection that inspired Hamilton’s big insight—perhaps relatively high levels of genetic interrelatedness among individuals within a species relates in an important way to the amount of altruism we expect to see within that species. And this idea relates importantly to Hamilton’s theory of inclusive fitness. Inclusive fitness, described in the first chapter, suggests that there are two distinct methods by which an organism can increase its fitness or levels of reproductive success.

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