Chapter 1
Charles Darwin observed that
closely related organisms typically varied across geographic locations
separated by physical barriers and across geological periods separated by long
time intervals. Darwin reasoned that a process of Natural Selection, analogous
to the selective breeding of domestic animals, created differential survival
and reproduction of certain individuals within a population. Eventually, over
many generations, populations were transformed by natural selection into new
species. A second Englishman, Alfred Russel Wallace, independently developed
the concept of Natural Selection and the general theory was presented to the
Scientific community with excepts from both Darwin and Wallace in 1858.
An unshakable foundation for
Darwinian evolution theory was provided by the development of modern genetics.
Understanding that traits were transmitted as discrete, non-blending units
(genes) led to an understanding of evolution as a sustained, directional shift
in population gone frequencies. Spontaneous changes in genes (mutations)
provide new raw material for evolutionary change. Delineating the chemical
structure of DNA, the molecule of heredity has made it possible to study
evolution at the molecular level.
From the inception of
evolutionary theory, it was understood that behavioral traits were shaped by
Natural Selection just like morphological and physiological traits. Charles
Darwin understood this, as did the American philosopher and psychologist
William James. William James founded the Functionalist approach in psychology,
which is based on the idea that complex mental functions are evolved traits.
This adaptationist approach
to human psychology fell out of favor for nearly a century as a consequence of a
number of tragic historical events. Darwinian theory was used as a prop to
support a number of versions of the Naturalistic fallacy. Social Darwinists
argued that the exploitation of the poor by the rich was just the natural order
of things and Nazi death camps were created to eliminate “inferior” races.
Partially as a result of these abominations, behavioral theories based on
environmental determinism were embraced by psychologists (behaviorists) and
anthropologists (cultural relativists).
Discoveries in the science
of ethology (animal behavior) and sociobiology, such as the concept of
inclusive fitness provided the basis for the modern reemergence of an
adaptationist approach to human psychology, evolutionary psychology. Evolutionary
psychology focuses on the evolved psychological mechanisms that comprise the
mind as the central locus of behavioral adaptation. Evolutionary psychologists use information from a variety of sources to
identify which aspects of human behavior represent evolved psychological
mechanisms. The validity of the hypothesized adaptations is tested by
generating and verifying specific predictions that are implied by evolved
functionality as well as testing predictions that follow from alternative
hypotheses. The interdisciplinary nature of evolutionary psychology gives it an
inherently sound scientific basis.