>Much concerning a theory which relates brain size, DHEA, testosterone
>and human evolution.
>Darwinians, myself included, will have a hard time taking this theory
>seriously. What is selected for directly is not hormone levels or  
>brain size, but behavior. Any given behavior is likely to be
>influenced by many biochemical factors, not just a few as implied by
>Mr. Howard's argument.
>    In particular, it is implausible that changes in brain size over a
>number of different hominid species can be attributed to the global
>effects of the same few hormones for a series of different hominids.
>Also any evolutionary increase in brain size is likely to be due to a
>selective pressure for some critical behaviors, which may be
>facilitated by the increase in the size to those parts of the brain
>which affect that behavior. The size of the brain is a very crude
>evolutionary measure.

>Agreed -- any theory that tries to reduce a complex, multi-dimensional
>process like human evolution to a single, simple causative agent, like
>testosterone, isn't a theory -- it's a cartoon.
>Paul Myers                               Department of Biology

>http://fishnet.bio.temple.edu/           Philadelphia, PA 19122

> Much concerning a theory which relates brain size, DHEA, testosterone
> and human evolution.

> Darwinians, myself included, will have a hard time taking this theory
> seriously. What is selected for directly is not hormone levels or  
> brain size, but behavior. Any given behavior is likely to be
> influenced by many biochemical factors, not just a few as implied by
> Mr. Howard's argument.