Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site faron.UUCP Path: utzoo!linus!faron!sidney From: sidney@faron.UUCP (Sidney Markowitz) Newsgroups: net.kids,net.med Subject: Re: Changing Left-handedness to Right-handedness Message-ID: <329@faron.UUCP> Date: Thu, 15-Aug-85 11:26:59 EDT Article-I.D.: faron.329 Posted: Thu Aug 15 11:26:59 1985 Date-Received: Sun, 18-Aug-85 22:38:37 EDT References: <1076@ihlpg.UUCP> <29639@lanl.ARPA> Reply-To: sidney@faron.UUCP (Sidney Markowitz) Organization: The MITRE Corporation, Bedford, MA Lines: 43 Xref: linus net.kids:1544 net.med:1855 [replace this line with your bug] The 16 August 85 issue of "Science" has an article titled "The Brain Connection: The Corpus Callosum is Larger in Left-Handers" on pg 665. The corpus collosum, the portion of the brain that connects the two hemispheres, is an average of 11% larger in left-handed and ambidextrous people than it is in right-handers. What does this mean? Well, besides the interesting speculations regarding the need for more cross-hemispheric activity because of less segregation of functions according to hemisphere, there's the following quote from the article, discussing possible mechanisms for the difference in size, attributing it to a *reduction* in the initial number of neurons that occurs in the righties, but to a lesser degree in the lefties: Elimination of callosal collaterals has been suggested to underlie this decrease in fiber number and to be completed soon after birth. If more fibers do exist in the larger callosa of mixed-handers, the neuroanatomical difference between hand-groups may be related at least in part to axonal elimination, which occurs prior to most environmental influences. In other words, handedness appears to be related to details of the brain structure which are fixed shortly after birth. It doesn't make much sense to try and train a kid to be a righty. By the way, a disproportionate number of mathematicians and computer scientists (especially those that are female) are left-handed, and of professional musicians (especially the more successful) are ambidexterous. Sidney Markowitz ARPA: sidney@mitre-bedford UUCP: ...{allegra,decvax,genrad,ihnp4,philabs,security,utzoo}!linus!sidney -- Sidney Markowitz ARPA: sidney@mitre-bedford UUCP: ...{allegra,decvax,genrad,ihnp4,philabs,security,utzoo}!linus!sidney