Evolutionary Psychology and Human Relationships

What is Evolutionary Psychology

Evolutionary psychology is the study of behavior, thought, and feeling through the lens of evolutionary biology. Modern evolutionary psychology is a synthesis of developments in several fields, including zoology, ecology, cognitive neuroscience, anthropology, and social psychology. Central to this synthesis is Charles Darwin's theory of evolution by natural selection. Following Darwin, evolutionary psychologists presume that human behaviors reflect the influence of physical and psychological predispositions that helped our ancestors survive and reproduce.

The first question an evolutionary theorist asks about any feature of a living organism is this: What is its adaptive function? How does this feature help the organism survive and, more importantly, reproduce? Why do hawks, but not moles, have excellent vision? Why do peacocks, but not peahens, have bright feathers? Evolutionary psychologists examining human relationships consider the functional implications of human evolutionary history (e.g., living in omnivorous hierarchical primate groups populated by kin) for relationships with friends, lovers, enemies, and kin. Although we humans may take romantic relationships, friendships, and status hierarchies for granted, many of our mammalian relatives never concern themselves with the questions that often consume our days. As discussed later, the adaptive function of a particular feature can take different forms depending whether the human being in question is a male or a female, young or old, and currently mated or not.

Domain-Specific Mechanisms

People must make important decisions within several different domains—some are nonsocial (what to eat, how to keep warm, for example); others are social (who to trust as a friend, whom to make a romantic overture toward, etc.). A key assumption of an evolutionary approach is that different problems cannot be solved using one single-domain general rule. Although it is generally true to say that people interact with others to get rewards, or to maximize benefits and minimize costs, such explanations fail to explain why and when some things are pleasant and others are unpleasant. A kiss may be a reward or a punishment, depending on who is kissing whom (a lover vs. a panhandler, for instance). Likewise, winning a competition may feel bad or good, depending on who is being beaten (one's 5-year-old daughter vs. an arrogant coworker, for example). From an evolutionary perspective, different relationships are assumed to be controlled by different psychological mechanisms, each characterized by different decision rules.

This assumption is supported by a broad literature suggesting that animal's brains are composed of a number of specialized “modular” mechanisms. For example, birds use different memory systems and different rules for remembering song, tastes of poisonous food, and locations of food caches. Likewise, humans inherit different memory [Page 545]systems for dealing with different, sometimes conceptually incompatible tasks, including learning language, learning to avoid poisonous foods, and remembering other people's faces. Researchers interested in human relationships have begun to apply the concept of domain specificity to understanding the differences between friendships, status hierarchies, family relationships, and short- and long-term romantic relationships, all of which seem to operate according to slightly different rules.

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