Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!usc!orion.oac.uci.edu!ucivax!gateway From: turpin@cs.utexas.EDU (Russell Turpin) Newsgroups: soc.feminism Subject: Re: physiological differences between male and female brains Summary: Beware of extrapolating from individual brain topology. Message-ID: <18425@cs.utexas.edu> Date: 13 Mar 91 18:31:01 GMT References: <1991Feb22.215346.8448@aero.org> <1991Mar8.034313.29112@ux1.cso.uiuc.edu> Organization: U. Texas CS Dept., Austin, Texas Lines: 36 Approved: tittle@ics.uci.edu Nntp-Posting-Host: zola.ics.uci.edu ----- In article <1991Mar8.034313.29112@ux1.cso.uiuc.edu> forbes@aries.scs.uiuc.edu (Jeff Forbes) writes: > According to _Evolution of the Vertebrate Brain_, the adult human > female brain (taking into account body height) is on the average 200 > grams less than that of the adult human male brain, using the same > scaling. What does this mean? Possibly nothing more than another odd > medical statistic. You got it. There is quite a bit of variation in cranium shape, including overall size, overall shape (thus, some heads are egg-shaped, some more round, some people have high foreheads, etc), and also in the particular bumps and dents in each skull. Despite the popularity of phrenology in the previous century, which found the reason for everything from criminal behavior to the particular nature of women (!) in the shape of the skull, there is no evidence that skull shape (and hence, brain size) has any correlation with intelligence, cognitive abilities, character, or personality. (The exception is when a particular skull feature indicates some other problem. For example, some people attribute Blaise Pascal's recurring headaches and religious visions to a cranial suture that grew into the brain rather than closing properly.) The brain is actually quite adaptable while the child grows. There was one case where the brain's ventricles, for some reason I forget, grew into a large cavity, forcing the rest of the brain structure into a relatively thin hemisphere next to the skull. This did not result in any functional problems. One American Indian tribe would keep their male infants in an odd kind of cradle that forced the head between two slanted boards, in order to give the head a flat shape. (Who knows how these things develop? Perhaps this was an early gender-based AA program.) Russell