Download Good Genes Three key bits of conceptual background.

Good Genes
Three key bits of conceptual background.
- What “a gene for X” means.
- Competition between genes.
- Popularity of genes.
The concept of “good genes.”
Psychological implications.
- Good genes, social perception, and sexual attraction.
- Research on “the scent of symmetry”.
What “a gene for X" means:
(3 different ways of saying same thing)
- the gene is probabilistically associated with X.
- All other things being equal, having one particular variant of the gene (compared to
any other variant of the gene) tends to be associated with a somewhat different
outcome on characteristic X.
- When measured across a population, there is a nonzero correlation between (a)
variation on the specific gene, and (b) measureable outcome on characteristic X.
Competition between genes:
Dawkins: “It is differences that matter in the competitive struggle to survive; and it is
genetically-controlled differences that matter in evolution.”
Evolution isn’t influenced so much by the effects associated with a particular gene (or
variant of a gene). It is influenced by differences between effects associated with
different genes (or variants of genes).
Popularity of genes:
Dawkins: “Evolution is the process by which some genes become more numerous and
others less numerous in the gene pool. It is good to get in the habit, whenever we are
trying to explain the evolution of some characteristic, such as altruistic behavior, of
asking ourselves simply: ‘What effect will this characteristic have on frequencies of
genes in the gene pool?’”
Research within evolutionary psychology is informed by answers to this question:
What specific genetically-based psychological tendencies were likely to have made a
gene more ‘popular’ under ecological circumstances that characterized ancestral
populations?
The concept of “good genes”
Dawkins on “good genes”: “They have an effect on the embryonic development of each
successive body in which they find themselves, such that that body is a little bit more
likely to live and reproduce than it would have been under the influence of the rival gene
or allele.”
The “goodness” a gene is defined jointly by:
- How well it builds a body.
- Eventual reproductive success of that body.
Psychological implications
Three useful questions to ask:
(As a means of generating testable hypotheses)
Who might be especially sensitive to evidence of “good genes”?
When might they be especially sensitive to this evidence?
What phenotypic traits might provide this evidence?
The scent of symmetry
(Research by Gangestad & Thornhill, and others)
Two hypotheses:
Women judge the smell of highly symmetrical men to be more sexually attractive than
the smell of less symmetrical men.
This effect varies across the menstrual cycle, and occurs primarily during the most
fertile phase of the cycle.