Stuart Newman wrote:
Given what genes actually do (specify primary sequences of proteins, and
they don't even do that in a straightforward fashion--almost every RNA
transcript in vertebrates is spliced, and at least half are alternatively
spliced), the idea of a "genetic explanation" for any trait at all, let
alone behaviors and beliefs, is problematic. There are clearly some cases
in which morphology (e.g., wrinkling of peas, number of fingers in humans),
a disease propensity (for sickle cell disease, cystic fibrosis), a sensory
capability (color blindness, perfect pitch), and undoubtedly behavioral
propensities, are strongly influenced by one or more genes. But in none of
these cases does there exist a genetic explanation of the trait affected by
the gene variants.
REPLY: From a developmental systems perspective "genetic explanations" are not
problematic, they are false. Genes don't determine outcomes at any level of
explanation. However, genes obviously will be involved in outcomes that are
selected for. Whether specific outcomes in human psychology and behavior are
selected for is an empirical matter.
Obviously species-typical outcomes may indicate selection at work and so
evolutionary psychology is correct to concentrate on these. An emphasis on
Tinbergen's four questions concerning proximal, developmental, functional and
evolutionary approaches helps us to formulate specific hypotheses that can be
assessed on a number of different levels of analysis.
Of course a stable outcome need not be selected for, biological explanations do
not reduce to genetic explanations, and adaptations need not necessarily
be adaptive in the current environment.
With all due respect this is simple, basic biology that no one in evolutionary
psychology should require any tutoring on. To be honest I find it difficult to
believe that any biologist would write the following:
"It is clear, however, that inheritance of traits almost never means there
are genes "for" that trait, and differences between individuals with regard
to a trait, even if the trait breeds true, doesn't necessarily mean that
there are allelic (gene sequence) differences between those individuals. So
what are evolutionary psychologist talking about?"
You aren't seriously offering this as a problem for evolutionary psychology?
Or is your position that we should simply discount any evolutionary
hypothesis if there is some other non-evolutionary hypothesis, however
implausible? Even Gould wouldn't go along with you on this.
Ian Pitchford PhD CBiol MIBiol
The Human Nature Review
Department of Psychiatry
Creighton University School of Medicine
3528 Dodge Street
Omaha, NE 68131, USA