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From: ka@hou3c.UUCP (Kenneth Almquist)
Newsgroups: net.flame
Subject: Re: Breeding of Humans
Message-ID: <153@hou3c.UUCP>
Date: Fri, 23-Dec-83 00:01:30 EST
Article-I.D.: hou3c.153
Posted: Fri Dec 23 00:01:30 1983
Date-Received: Sat, 24-Dec-83 11:11:08 EST
References: <331@hocda.UUCP>, <1123@rocksvax.UUCP> <1128@rocksvax.UUCP> <1160@mhuxm.UUCP> <677@ut-sally.UUCP>
Organization: Bell Labs, Holmdel, NJ
Lines: 21

In response to Prentiss Riddle's question, intelligence is definitely
inheritable.  Realizing that identical twins are geneticly identical, C.
Burt examined the correlations between the intelligence of various pairs
of children in 1958 (The Inheritance of Mental Ability.  Amer. Psychol.
13: 5-10):

	RELATIONSHIP				CORRELATION
	Idential twins raised together		.92
	Identical twins raised separately	.77
	Nonidentical twins raised together	.55
	Nontwin siblings raised together	.53
	Nontwin siblings raised separately	.51
	Unrelated children raised together	.26

This (as well as more recent studies) shows that intelligence is affected
by heredity.  The fact that there is a higher correlation between identical
twins raised separately than between nonidentical twins raised together
indicates that there is a definite hereditary component to intelligence.
Although the data here do not prove it, intelligence is also affected by
environment.  In particular, a poor environment can decrease intelligence.
					Kenneth Almquist