One of the problems with the model as stated here
is that the feedback mechanism isn't totally efficient.
That is, we all agree that intelligence is useful for
its "survival value", BUT . . .
an individual who happens to have high intelligence
can still die before reproducing, due to famine,
accident, war, or disease.
or become gay, and fail to reproduce at all.
In the animal kingdom, let us surmise a fish that has
won the molecular lottery and has developed (in a time
of climactic change) a greater resistance to drought
(say, a lungfish, perchance)? The model does NOT talk
about how this protects it from being eaten while still
an infant, before it passes on its genes.
Or what these type of events do to affect the RATE of
evolutionary development.
Not true or false, but incomplete, up to a point.
[Asbestos suit donned.]
Ain't there a gene for that?????
;^)
Sort of like politics. You may have noticed that for most creatures, life is cruel and short.
The desirability or quality of genes is measured entirely by whether the carrier reproduces. There is no other measure.
Many observed traits traits, such as skin color, intelligence, physical health and strength are multivariate, they are the result of many genes working together. There is, for example, a theory that autism is (in an oversimplified way) an overdose of genes responsible for intelligence. Autistic people seldom reproduce, but their relatives will have lesser doses of the same genes, and will thrive as a result. Their might be a similar dynamic involved in homosexuality, if there is, in fact, a genetic link.
The other thing that needs to be considered is varying environments. There are times when physical strength is more useful than intelligence, and vice-versa. And there are times when quirky traits, such as sickle-cell trait, are more useful than "normal" health.