Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site ecsvax.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!mcnc!ecsvax!dgary From: dgary@ecsvax.UUCP (D Gary Grady) Newsgroups: net.bio Subject: Re: Identical twins and handedness Message-ID: <295@ecsvax.UUCP> Date: Thu, 22-Aug-85 12:52:49 EDT Article-I.D.: ecsvax.295 Posted: Thu Aug 22 12:52:49 1985 Date-Received: Sun, 25-Aug-85 06:16:17 EDT References: <233@drutx.UUCP> <289@ecsvax.UUCP> Organization: Duke U Comp Ctr Lines: 19 A recent article in SCIENCE (18 Aug 85) indicates left-handed and ambidextrous persons have a larger corpus callosum than right-handers. The corpus callosum is the structure that connects the hemispheres. One possibility is that in left-handers and the ambidextrous, brain function is not as specialized between the two hemispheres of the brain, so more interhemispheric communication is needed. This would suggest that in twins with different handedness, their brains would be quite significantly different. Nature-vs-nurture studies involving twins have tended to assume identical twins have the same "nature" (so any observed difference would presumably be due to environmental factors). If it is true that identical twins tend to have different handedness, this assumption may be invalid. -- D Gary Grady Duke U Comp Center, Durham, NC 27706 (919) 684-3695 USENET: {seismo,decvax,ihnp4,akgua,etc.}!mcnc!ecsvax!dgary