that depression is adaptive because it leads us to give up on unattainable
goals and thereby save resources (Wrosch & Miller, 2009). There is somelogic to this position, but it is quite a leap to say that we were better able to
survive as a species because we have the capacity to become depressed.
To fully appreciate this limitation, consider the example offered by one
psychologist (Cornell, 1997). As discussed in Chapter 10, some researchers use
evolutionary theory to explain gender differences, such as why men are more
dominant, stronger, and more sexually promiscuous than women (Archer,1996; Gangestad & Thornhill, 1997). But imagine if just the opposite were
the case —that men were more timid and physically weaker than women, and
less likely to seek out multiple sex partners. One could use evolutionary theory
to explain these results as well. We could speculate that because men were free
to roam and did not have to protect offspring, the tendency for them to timidly
run away from potential fights evolved. Women evolved to be stronger becausechild-care responsibilities required them to carry children, lift them into trees
for safety, and fight off predators. And sexual promiscuity allowed a woman
to avoid the risk of pairing up with a man who might be unable to make herpregnant and thus not allow her to pass along her genes. As this example illus-
trates, if a theory can explain all possible outcomes, it cannot be tested. As a
result, the research support for many of the ideas postulated by evolutionary
personality psychologists remains relatively weak.
Another criticism is directed at theory and research on temperament.
Students and researchers may be bewildered by the lack of an agreed-uponmodel. One prominent model identifies three basic temperaments. Yet other
models describe five, seven, and nine temperament dimensions (Bates, Wachs, &
Emde, 1994). Students have a right to ask which of these is correct. More impor-
tant, it is difficult to make comparisons across investigations when researchers
rely on different names and descriptions for these temperaments. Is the “inhib-
ited”child the same as the “slow-to-warm-up ”child? We can hope that clearer
answers about the number and description of basic temperaments will be forth-coming as researchers continue to work in this area.
Like the trait approach, the biological approach offers few suggestions for
personality change. Although many ideas from this approach are probably use-ful for psychotherapists, there are no schools of psychotherapy based on this
perspective. On the contrary, the message from the biological approach is thatwe need to be more aware of some of the limitations on how much we can
change people. Therapists might do better to recognize that, because of biologi-
cal differences, not all clients will respond identically to their treatments.
SUMMARY
1. Hans Eysenck was an early proponent of the biological approach to per-
sonality. He argued that personality can be divided along three primary
dimensions. He called these extraversion –introversion, neuroticism, and
psychoticism. Research suggests that introverts are more sensitive to
stimulation than extraverts and that extraverts may be more attracted to
rewards. Eysenck argued that differences in personality are largely basedin inherited biological differences.248 CHAPTER 9 The Biological Approach