432 Part V Biological/Evolutionary Theories
understand that these strategies are not conscious with a plan or foresight in mind,
but rather are blind (nonconscious). Traits get “selected” simply because they lead
to greater survivability and hence more offspring with that trait survive to repro-
ductive age. These individuals, in turn, have more offspring. Darwin’s genius was
being the first (along with Alfred Wallace) to recognize this was the process that
drove evolution of all life forms.
Darwin realized there were certain traits that contradicted natural selection
because they directly made survival less, not more, likely. The big, bulky, color-
ful feathers of the peacock were a prime example. Why do such characteristics
exist if they make survival more difficult? His answer was sexual selection rather
than natural selection (Darwin, 1859; Miller, 2000). Sexual selection operates
when members of the opposite sex find certain traits more appealing and attractive
than others and thereby produce offspring with those traits. The key is that these
qualities have to be markers of fitness that can’t be easily faked. For instance, in
the example of the peacock, only males with the healthiest and brightest plumage
are most attractive to peahens. But plumage cannot be faked—that is, not just any
male can pretend to have the brightest plumage. In fact, the brightest plumage is
a true marker of fitness, that is, these really are the strongest and healthiest males
in the cluster/pride (Zahavi & Zahavi, 1997). In fact, these traits are handicaps
that only the truly strong and healthy can pull off. They signal to peahens, “Hey,
select me; I am the strongest and healthiest.” By mating with these peacocks,
peahens are unconsciously producing the strongest and healthiest offspring. In
humans, strength, physical beauty, dominance, intelligence, and status are quali-
ties many find attractive and are therefore sexually selected for. For example, a
recent study of over 400 individuals, many of whom were creative artists and
poets, revealed a positive correlation between creativity and sexual success. That
is, more creative people were also more sexually active (Nettle & Clegg, 2006).
The researchers argue that their findings support the theory, first proposed by
Darwin and more recently by Geoffrey Miller (2000), that human creative ability
is a sexually selected trait because it is a quality that increases one’s attractiveness
to members of the opposite sex.
The evolutionary process (natural and sexual selection and chance) results in
three distinct outcomes: adaptations, by-products, and noise (D. Buss, 1999; Tooby
& Cosmides, 1992). Adaptations are evolved strategies that solve important sur-
vival and/or reproductive problems. Adaptations are often the products of natural
or sexual selection and must have a genetic or inherited basis to them. Sweat
glands, for example, are adaptations because they solve the problem of thermal
regulation. Taste preferences and sexual attraction are also adaptations. We like
sugary and fatty foods because they are good sources of energy and in earlier
evolutionary times were relatively scarce. Human intelligence and creativity are
adaptations because they facilitate adaptive solutions to problems of survival (Feist,
2006; Miller, 2000).
By-products are traits that happen as a result of adaptations but are not part
of the functional design (D. Buss, 1999; Tooby & Cosmides, 1992). By-products
“come along for the ride” of natural or sexual selection. Scientific ability or driv-
ing skill is each a by-product of adaptations. We clearly did not evolve to do