Question

What criteria would you use to determine whether an observed behavior was an evolved psychological mechanism in a species? Use lecture notes about the characteristics of evolved psychological mechanisms to answer this question, as well as anything from the Alcock readings that you think addresses this question and Identifying Adaptive Problems by Buss (this reading sent to you via email). You might want to also use Observing and Analyzing Human Non-verbal Behavior by Bernstein and Living our Limbic Legacy by Navarro and Karlins (these two readings also emailed to you earlier in the class) and Yawning, by Robert Provine (in Exploring Animal Behavior). Using these last three readings may depend on what behavior you decide to assess as an EPM.

Answer 1

What criteria would you use to determine whether an observed behavior was an evolved psychological mechanism in a species?

• A psychological adaptation is a functional, cognitive or behavioral trait that benefits an organism in its environment. Psychological adaptations fall under the scope of evolved psychological mechanisms (EPMs), however, EPMs refer to a less restricted set. Psychological adaptations include only the functional traits that increase the fitness of an organism, while EPMs refer to any psychological mechanism that developed through the processes of evolution.
• These additional EPMs are the bi-product traits of a species’ evolutionary development (spandrels), as well as the vestigial traits that no longer benefit the species’ fitness. It can be difficult to tell whether a trait is vestigial or not, so some literature is more lenient and refers to vestigial traits as adaptations, even though they may no longer have adaptive functionality.
• For example, xenophobic attitudes and behaviors appear to have certain EPM influences relating to disease aversion,however, in certain environments these behaviors may actually have a poor effect on a person's fitness. The principles of psychological adaptation rely on Darwin’s theory of evolution and are important to the fields of evolutionary psychology, biology, and cognitive science.

Evolved adaptation vs learned behaviour

• An area of disagreement arises between evolutionary psychologists, cognitive scientists and behaviourists on where to draw the line on what is considered a psychological adaptation, and what is considered a learned behaviour.^[5] Where behaviourism explains certain behaviours as conditioned responses, cognitivism may push that these behaviours arise from a psychological adaptation that institutes a preference for that behaviour.
• Evolutionary psychology proposes that the human psychology consists primarily of psychological adaptations, which is opposed by the tabula rasa or blank slate model of human psychology. Early behaviourists, like B.F. Skinner, tended to the blank slate model and argued that innate behaviors and instincts were few, some behaviourists suggesting that the only innate behavior was the ability to learn.
• On the other hand, Steven Pinker presents the cognitivist perspective in his book, The Blank Slate, in which he challenges the tabula rasa models and argues that human behaviour is shaped by psychological adaptations.
• This difference in theory can be seen in research on modern human sexual preferences, with behaviourists arguing that attraction has conditioning influences, such as from the media or cultural norms, while others arguing it is based on psychological adaptations. However, sexual preferences are a difficult subject to test due to the amount of variance and flexibility exhibited in human mate choice.
• A hybrid resolution to psychological adaptations and learned behaviours refers to an adaptation as the species’ capacity for a certain behavior, while each individual organism still needs to be conditioned to exhibit that behaviour. This approach can explain language acquisition in relation to linguist and cognitive scientist Noam Chomsky's model of human language.
• His model supports that the capacity for language is a psychological adaptation (involving both the language necessary brain structures and disposition for language acquisition), however, children lack any particular instantiation of language at birth, and must instead learn one in the their environment.