[tips] RE: Those amazing identical twins

[John Kulig]

So long as you have a control comparison, such as di-zygotic twins similarly separated. IF beer choice is more similar for MZ than DZ, we'd have evidence of genetics. The MZ - DZ comprisons assume both groups of twins are treated the same (equal-environment assumption). When twins are separated early in life, you assume the environment did not work to make MZ more similar. Whenever I show my intro class the pictures of the Jim twins and other fascinating MZ similarities (or coincidences) I have to work very hard to remind them (and me) this evidence, by itself, is not conclusive. You need a control group, and this is where DZ comes in.   Though to get the full picture, do the full array of genetic similarity - from no relations through cousins and aunts, to parents, siblings, and then twins. The correlation (sort of) between similarity in genotype and similarity in phenotype is the heritability coefficient.   Tangent: An interesting aspect of the environmental issue is that people shape their own environment. My brother is a mathematican whose environment (from an early age) included massive doses of mathematic books. But, of course, he selected those books himself (covariance of genetics & environment factors). ----------------------------- John W. Kulig Professor of Psychology Director, Psychology Honors Plymouth State University Plymouth NH 03264 -----------------------------   From: Michael Sylvester [mailto:[EMAIL PROTECTED] Sent: Monday, November 13, 2006 8:15 PM To: Teaching in the Psychological Sciences (TIPS) Subject: [tips] Those amazing identical twins There are reports of identical twins raised apart  who show  identical behaviors and interests. The assumption is that genetics have a definitive role in this. What could be alternative explanations? If one adopted twin was raised in Canada and chooses Molson as the preferred beer,and the other was raised in New York and also chooses Molson as the preferred beer,wouldn't this be a choice influenced by genetic factors?   Michael Sylvester,PhD Daytona Beach,Florida --- To make changes to your subscription go to: http://acsun.frostburg.edu/cgi-bin/lyris.pl?enter=tips&text_mode=0&lang=english --- To make changes to your subscription go to: http://acsun.frostburg.edu/cgi-bin/lyris.pl?enter=tips&text_mode=0&lang=english