The Evolutionary Psychology FAQ

Edward H. Hagen, Institute for Theoretical Biology, Berlin

Do evolutionary psychologists think that everything is an adaptation?

Evolutionary adaptation is a special and onerous concept that should not be used unnecessarily, and an effect should not be called a function unless it is clearly produced by design and not by chance. When recognized, adaptation should be attributed to no higher a level of organization than is demanded by the evidence. George C. Williams, opening words of Adaptation and Natural Selection 1966

No. From an adaptationist perspective, there are four types of phenomena: adaptations, byproducts of adaptations, malfunctions of adaptations, and noise (this typology can be refined, although I won't do so here). Each of the first three types of phenomena are the subject of serious research efforts in evolutionary psychology. For example, Martin Daly and Margo Wilson primarily offer byproduct hypotheses for homicide in their landmark book Homicide (A. de Gruyter, 1988), a work that has been cited over 450 times according to ISI. Daly and Wilson are highly respected researchers in evolutionary psychology. They are considered pioneering researchers in the field, and currently edit the principle evolutionary psychology journal, Evolution and Human Behavior. In Homicide, Daly and Wilson argue that many adult homicides are byproducts of male status striving. They also discover that stepparents, by almost two orders of magnitude, are the single biggest risk factor for child abuse and infanticide. They do NOT argue that infanticide is an adaptation expressed in stepparents. Rather, they argue that the high rates of abuse and infanticide are a byproduct of a lack of parental solicitude. That is, that parenting requires an enormous degree of care and attention, but that the suite of parental care adaptations may fail to fully activate in stepparents due to a lack of genetic relatedness to the offspring. The resulting injuries and deaths are byproducts of a RELATIVE degree of decreased effort, and are not the products of adaptive behavior.

Simon Baron-Cohen is an influential researcher exploring autism from an evolutionary psychological perspective (a quick search on a psychological research journal database yielded over 100 articles written by him). Far from arguing that autism is an adaptation, Baron-Cohen argues persuasively that it results from a malfunction of a 'theory-of-mind' module, a psychological adaptation designed to allow humans to infer the mental states of others. This theory has been quite influential, and has stimulated a significant amount of research. Similar approaches are being applied to schizophrenia by Christopher and Uta Frith, among others.

It is true that many functional hypotheses have been offered for a variety of psychological phenomena, and it is also true that most of these hypotheses are probably wrong. However, hypotheses outnumber established theories in just about any field you care to name, and evolutionary psychologists are no less discriminating than other scholars. Every field has its 'brass ring.' For particle physicists, it is a new particle. For entomologists, it is a new insect taxon. For evolutionary psychologists, the brass ring often involves identifying a new psychological adaptation. Successfully identifying a new psychological adaptation will substantially increase a researcher's reputation. That's why so many functional hypotheses have been proposed. By the same token, other researchers will not easily accept new hypotheses--to accept a shaky idea would diminish their reputation. Just as particle physicists subject claims of new particles to intense scrutiny, so do evolutionary psychologists subject claims of new adaptations to intense scrutiny (I know, I've experienced this first hand). In my experience, the critiques of functional hypotheses by evolutionary psychologists are far more incisive than those of researchers with less experience in the field. This isn't surprising, really, but may be news to critics of evolutionary psychology.

Copyright 1999-2002 Edward H. Hagen