Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site tardis.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!wjh12!tardis!rst From: rst@tardis.UUCP (Robert Thau) Newsgroups: net.bio,net.women Subject: Re: Left vs right brains Message-ID: <10042@tardis.UUCP> Date: Thu, 18-Apr-85 20:49:00 EST Article-I.D.: tardis.10042 Posted: Thu Apr 18 20:49:00 1985 Date-Received: Sun, 21-Apr-85 02:02:31 EST References: <1649@decwrl.UUCP> <1649@ittvax.UUCP> <5754@duke.UUCP> Distribution: net Organization: Harvard University, Cruft Lab (TARDIS) Lines: 80 Xref: linus net.bio:35 net.women:4286 > In article thau@h-sc1.UUCP (robert thau) writes: > >> > Does anyone know why (historically and currently) women's shirts button > >> > right over left and men's button left over right (or is it vice versa)? > >> > Why make the thing differently depending on who is supposed to wear it? > >> > >> A possible explanation comes from the biology of the brain... > >> [some stuff unlikely to explain the differences between mens' and > >> womens' shirt buttons] > >> > >Handedness seems to me to be a lot more relevant that 'brainedness' > >(whatever that means), and a majority of both sexes are right-handed. > > > The meaning of 'more developed' in the above quote is not clear. I wrote "more relevant," not "more developed." I still think that handedness is a lot more relevant than brainedness to shirt buttons. The hands are closer to the buttons. However ... > In addition to the fact that most people are right handed, > most people are left brained with respect to language > in the sense that if the language areas in the left hemisphere > are injured, recovery is slow and incomplete. If the analogous areas > in the right hemisphere are injured, recovery is much faster and more > complete. The sex difference in language dominance, if it exists, is small. > The neurological differences between males and females is much more > subtle (and less well understood, certainly by me and Im pretty sure > by people who study these things). True as far as it goes; in fact there is even a correlation with handedness (lefties are about 50-50 for language dominance, righties are almost all left-brained for language). However, I don't think it's at all proper to equate "left-hemisphere language dominant" with simply "left-brained." What I really meant by the "whatever that means" is that the original posting (long ago, far away) seemed to smack of some trendy pop-psych hype based on the fact that (gasp!) the brain has two hemispheres. The idea is that there are people who have "right-brain" or "left-brain" modes of thought, with "right-brain" (visual, intuitive) generally considered somehow better. I once took one of these quizzes which is supposed to tell you whethe you are right- or left- brained. I came out in the middle. With that background ... It is known that there are differences between brain hemispheres, like language dominance, but the extent and meaning of the differences is just not understood. For example, the areas corresponding to the left-hemisphere speech centers in the right brain are active when a person is talking, despite the evidence from stroke recovery which seems say that they aren't used. The language areas have been known since the 1800's, but the laterality stuff hit high gear with some experiments in the 1950s by Roger Sperry. His subjects were epileptics who were treated by separation of the two cerebral hemispheres. Subsequently, the two hemispheres could be coaxed to act like two very different "people" stuck in one skull. By and large, the left brain had trouble with visual tasks but could do language well, while the right brain was the other way 'round. (Sound familiar?) However, to this day the extent to which these differences reflect differences in what the hemispheres can do (as opposed to ingrained habits) is simply unknown. For that matter, the operation's effects on the brain itself aren't entirely well characterized. For all anyone knows, the division of tasks is imposed after the operation, so that the two brains stay out of each others' way, based perhaps on a much less rigid division of labor in the normal brain. There's also a semantic problem --- as Joel pointed out, most people are left-brain dominant for language. However, the right hemisphere is almost certainly dominant for other tasks. To use an inappropriate example, most people are right-handed for most tasks, but prefer the left hand for some. Now, where this leaves the article in Discover magazine which claimed to describe right- and left-brain personality types I don't know. I certainly hope that the personnel departments which were alleged to be trying brainedness as a job qualification have as shaky a basis in known fact as their theories do. Contrary opinions welcomed. Robert Thau [bio major] rst@tardis.ARPA h-sc1%thau@harvard.ARPA