Personality, Reading # 2, Ch. 9, p.304-317
Evolutionary Theory and Personality
Biologists and psychologists distinguish between two kinds of explanation: Ultimate causes and
Ultimate causes refer to explanations associated with evolution (why behaviour of interest evolved
and the adaptive functions it served).
Proximate cause explanations refer to biological processes operating in the organism at the time
the behaviour is observed.
Contemporary psychologists’ analyses of evolutionary forces differ and as a result, there exist
“evolutionary psychologies.” Main points of difference involve the degree to which psychological
tendency is hardwired versus being a tendency that arises as a result of interactions between
biology and culture.
Writers who highlight the evolutionary hardwired aspects of human nature have gained much
prominence in personality psychology. In this approach, contemporary human functioning is
understood in relation to evolved solutions to adaptive problems faced by the species over millions
of years. Basic psychological mechanisms are the result of evolution by selection, that is, they exist
and have endured because they have been adaptive to survival and reproductive success. The
fundamental components of human nature can be understood in terms of evolved psychological
mechanisms that have adaptive values in terms of survival and reproductive success.
Four points about evolution and the human mind are highlighted in this approach to evolutionary
1) The features of mind that evolved are ones that solve problems that are important to
2) The evolved mental mechanisms are adaptive to the way of life of hundreds of centuries ago,
when our ancestors were hunters and gatherers. An implication is that we may have evolved
psychological tendencies that no longer are good for us. Ex: our taste preference for fat.
3) Evolved psychological mechanisms are domain-specific. The body and mind consists of
evolved mechanisms that solve specific problems that occur in specific types of settings, or
domains. For example, evolution does not give us a general tendency to be afraid, but instead
selects for psychological mechanisms that cause us to fear specific stimuli that have been
threats to humans across the course of evolution.
4) This concerns the components and overall structure of the mind, or what is commonly called
the “architecture” of mental systems. One view of mental architecture is that the mind is like
a computer; evolutionary psychologists reject this conception of mental architecture. A core
idea of evolutionary psychology is that the mind contains multiple information processing
devices, each of which processes information from one specific domain of life. Since many
different problems arise in different domains of life, the mind is said to consist of multiple
domain-specific mental mechanisms. These mechanisms often are called mental “modules,” a
term that is meant to capture the fact that they are special-purpose mechanisms designed to
carry out a domain-specific mental function.
A) Social Exchange and the Detection of Cheating
Cosmides explored a particular type of social setting and associated problem that, she reasoned,
has been of significance throughout the course of evolution. The social setting involves “social
exchange,” that is, the exchange of goods and services. Throughout evolution, part of people's
social interaction has involved the mutual exchange of beneficial goods. In any such exchange, it
is important to avoid being cheated. The ability to detect cheating has survival value. Cosmides
reasoned that the mind contains distinct systems for the detection of cheaters. Studies suggest that the ability to solve cheating problems is a human universal. Findings suggest
that there exists a specific neural subsystem of the brain that has evolved to solve such problems.
B) Sex Differences: Evolutionary Origins?
The evolutionary psychologist’s reasoning is that, throughout evolution, male and female human
beings have had different roles to play as a natural result of biological differences between the
sexes. Differences, of course, are found in physical stature as well as in child care (ex: pregnancy,
breastfeeding). Men and women, as a result of facing somewhat different problems across the
course of evolution, are predicted to have somewhat different brains that predispose them to
different patterns of thinking, feeling and action.
Men and women also differ socially; sex differences could be socially constructed, rather than
being biologically caused. A core idea of evolutionary psychology, however, is that biology
determines sex differences. David Buss advanced the notion that evolved psychological
differences between men and women are seen as responsible for the gender differences we
observe in society.
a) Male-Female Mate Preferences
According to evolutionary theory, as introduced by Darwin, selection pressures across the
course of human evolution have produced sex differences in preferences for mates.
Two ideas underlie the contemporary evolutionary psychologist's analysis of sex differences:
1) Parental Investment Theory
The theory is an analysis of the different costs, or investments, that men versus women have
made in parenting throughout the ages. Biological differences between the sexes cause women
to invest more in parenting. Parental investment is greater for females because of the greater
“replacement costs” for them. it follows that females will have stronger preferences about
mating partners than will males and that males and females will have different criteria for the
selection of mates. Women need men to help with the burdens of pregnancy and childcare, and
thus should seek men who have the potential for providing resources and protection. Men
should be less interested in protection; instead, they are expected to focus on the reproductive
potential of a partner (the person’s youth and other biological markers of reproductive fitness).
2) Parenthood Probability Theory
Since women carry their fertilized eggs, they can always be sure that they are the mothers of
the offspring. On the other hand, males cannot be so sure that the offspring is their own, and
therefore must take steps to ensure that their investment is directed toward their own offspring
and not those of another male. It follows that males have greater concerns about sexual rivals
and place greater value on chastity in a potential mate than do females.
The following are some of the specific hypotheses that have been derived from parental
investment and parenthood probability theories:
1) A woman’s “mate value” for a man should be determined by her reproductive capacity
as suggested by youth and physical attractiveness. Chastity should also be valued in
terms of increased probability of paternity.
2) A man’s “mate value” for a woman should be determined less by reproductive value
and more by evidence of the resources he can supply, as evidenced by characteristics
such as earning capacity, ambition and industriousness.
3) Males and females should differ in the events that activate jealousy, males being more
jealous about sexual infidelity and the threat to paternal probability, and females more
concerned about emotional attachments and the threat of loss of resources.
Results from a questionnaire showed that males valued physical attractiveness and relative
youth in potential mates more than did females, consistent with the hypothesis. The prediction
that males would value chastity in potential mates more than would females was supported.
Females were found to value the financial capacity of potential mates more than did males and valued the characteristics of ambition and industriousness in a potential mate to a greater
extent than males, consistent with the hypothesis.
b) Causes of Jealousy
Most males reported greater distress over a partner’s sexual infidelity while most females
reported greater distress over a partner’s emotional attachment to a rival.
Males showed greater physiological distress in relation to imagery of their partner’s sexual
involvement and women showed greater physiological distress in relation to imagery of their
partner’s emotional involvement.
The results supported the hypothesis of sex differences in activators of jealousy.
c) Evolutionary Origins of Sex Differences: How Strong are the Data?
In recent years, new research findings have begun to raise questions about the validity of the
theory as it applies to sex differences in social behaviour.
In evaluating evolutionary psychology, a major question is whether patterns of sex differences
are found universally, that is, across all cultures of the