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Home : Other Subjects : Psychology Study Guides : 101 : Evolution and Genes : Evolutionary Psychology
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Evolutionary Psychology
Evolutionary psychology uses evolutionary theory to explain similarities in
psychological characteristics. According to evolutionary psychologists, patterns of
behavior have evolved through natural selection, in the same way that physical
characteristics have evolved. Because of natural selection, adaptive
behaviors, or behaviors that increase reproductive success, are kept and
passed on from one generation to the next.
Mating Behavior
Because reproductive success is such a hot topic in evolutionary
theory, evolutionary psychologists often choose to study mating behavior.
Researchers such as Robert Trivers have proposed that mating strategies
depend on the amount of parental investment made by males and females of a
species. Parental investment refers to all the resources spent
to produce and raise offspring. In many species, males and
females don’t make equal parental investments. The sex that invests less
competes with others of its sex to mate with the sex that invests more. The
sex that invests more in parenting tends to discriminate more when
selecting a mate.
Sexual Selection
Usually, the female of the species invests more in parenting. Females
of many species choose their mates based on certain characteristics, such as
large canine teeth in a male baboon or flashy tail feathers on a peacock,
which in turn means those traits will be passed on to their male offspring.
Biologists call this process sexual selection, which is related
to natural selection. Whereas natural selection results in adaptations that
make organisms more likely to survive, sexual selection just makes them more
likely to mate. Sometimes the adaptations that are a result of sexual
selection, such as flashy tail feathers, are not actually much help in terms
of survival.
Polygyny
A situation called polygyny arises when a single male
mates with many different females. Polygyny tends to occur in certain animal
species, notably those in which females invest more in parenting than males.
In a polygynous mating system, males compete with other males in order to
get access to females. Females tend to pick the winners of such
competitions. Picking winners helps to ensure that their offspring will have
good genes.
Problems
with Evolutionary Explanations
Scientists have used evolutionary theory to explain human behavior
patterns, such as a female tendency toward monogamy and a male tendency toward
promiscuity. However, other researchers argue that such explanations don’t apply
well to humans, because the theories stem from stereotypes. Humans behave in
complex and variable ways, and factors such as culture strongly influence this
behavior. Furthermore, it is difficult to tie variation in behavior to variation
in reproductive success. Evolutionary explanations also raise controversy
because people can use them to support various social and political agendas.
Some researchers criticize evolutionary explanations because anyone can
work backward from an observation to develop an evolutionary explanation. These
psychologists point out that the fact that a trait exists does not necessarily
mean that trait is adaptive. The trait may have been helpful earlier in our
human history but did not remain adaptive, or the trait could be a side effect
of another adaptive trait.
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