Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site watarts.UUCP Path: utzoo!watmath!watarts!mupmalis From: mupmalis@watarts.UUCP (mike upmalis) Newsgroups: net.followup,net.misc Subject: Re: Results of handedness survey Message-ID: <8334@watarts.UUCP> Date: Sat, 16-Mar-85 12:24:29 EST Article-I.D.: watarts.8334 Posted: Sat Mar 16 12:24:29 1985 Date-Received: Sun, 17-Mar-85 01:12:09 EST References: <649@mhuxt.UUCP>, <224@vaxwaller.UUCP> <5209@utzoo.UUCP> Organization: U of Waterloo, Ontario Lines: 39 Xref: watmath net.followup:4665 net.misc:7544 > > Certain tests seem to indicate that you either have a gene for > right handedness, or you are neutral. Right handedness is dominant. > The neutrals seem to spilt 50/50 into being left or right handed. > > Laura Creighton > utzoo!laura One of the more intreresting points that has not been really raised in this discussion or at least no applied is that hand use does not exist as a dichotomy in the population. People exhibit preference in their hand use and you notice a bimodal distribution in the population on preference. Dr. Phil Bryden at the University of Waterloo has read and written extensively on lateralization of function in the human brain. A bit of digression first. What is known about speech in humans is that in 90%+ of the population language is in the right hemisphere. A small number have it both hemispheres and the balance have it in the right hemisphere. Now the fun part, researchers into speech thought that the hemisphere that language is in can be co-related with hand use. The idea is that lefties are mirror image of righties and people with no hand preference might reflect a low level of lateralization. While the numbers follow this idea it is only a trend and not of predictive or modeling value. The next step was to measure actual hand use. Next time you eat dinner watch what peolpe do with the fork and knife. Do they switch the fork to the right hand after sawing away with their knife? When you brush your teeth do you switch hands, do you pitch a ball with your right hand and bat from the left side of the plate? While people look at writing as an indicator of handedness, there are a number of other indicators. The author above refers to Annet's model of hand use. One of the problems is that it cannot predict why men and females different on hand preference by extremity. Males tend to be more extreme on hand use while females tend to be closer while still being bimodally distributed. For those who are interested I would refer to a book by Phil Bryden on Cerebral Lateralization. -- ~~ Mike Upmalis (mupmalis@watarts)