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INTERPERSONAL RELATIONS AND GROUP
PROCESSES
Is Human Mating Adventitious or the Result of Lawful Choice?
A Twin Study of Mate Selection
David T. Lykken and Auke Tellegen
Pairs of middle-aged twins and their spouses provided data on 74 mainly psychological variables.
Neither spousal similarity nor idiosyncratic criteria could account for specific mate selection in
these 738 couples. Of the twins (and their spouses), 547 independently rated their initial attraction
to their twin’s mate (or to their spouse’s twin): Findings suggest that characteristics both of the
chooser and the chosen constrain mate selection only weakly. This article proposes that it is roman-
tic infatuation that commonly determines the final choice from a broad field of potential eligibles
and that this phenomenon is inherently random, in the same sense as is imprinting in preco-
cial birds.
The heart has its reasons that the reason knows not of.
—Blaise Pascal, ∕⅛hλ⅛, Section IY No. 277
Mate selection: choosing whom we hope will be our life’s
companion, the person who will contribute half the parenting
and halfthe genome for our children-our Windowsofopportu-
nity on genetic immortality-is perhaps the most important
choice we ever make. Whether mate selection is coolly rational
or emotionally intuitive, we assume that salient characteristics
of the chosen will be related in some sensible way to character-
istics of the chooser. In this article, we report a series of four
studies testing various models of mate selection. The first study
tests the similarity model, the hypothesis that we select mates
similar to ourselves. It is argued that the equity model, the hy-
pothesis that we seek a partner similar in “mate value” to our-
selves, can be regarded as a facet of the similarity model and
shares its limitations. The poverty model, which holds that
most people have few mating opportunities and must, in effect,
take what they can get, leaves unexplained the widely shared
perception of romantic couples that they have “found their one
and only.” The second study tests the idiographic model, the
hypothesis that we each act on idiosyncratic criteria that law-
fully determine mate selection. Study 3 is a test of the hypothe-
sis that monozygotic (MZ) twins, who are similar because they
share a common genome and similar rearing experiences and
David T. Lykken and Auke Tellegen, Department of Psychology,
University of Minnesota.
This research was supported by National Institute of Mental Health
Grant MH37860-07 and a University of Minnesota Graduate School
Grant to the Minnesota Twin Registry. We are indebted to four anony-
mous reviewers for their careful and constructive comments on a draft
of this article and to J. D. Lykken for statistical consultation.
Correspondence concerning this article should be addressed to Da-
vid T. Lykken, Department of Psychology, Elliott Hall, University of
Minnesota, Minneapolis, Minnesota 55455-0344.
who therefore tend to have similar tastes and make similar
choices, should be similarly attracted to the same spousal can-
didates. Study is a test of the related hypothesis that the
spouses of MZ ins, having become romantically attached to
one twin, should therefore have found their spouses’ cotwin
more attractive than, say, some random friend of their spouse.
The results of these studies have led us to conclude that,
whereas much human choice behavior is undoubtedly lawful
and, to some extent, predictable, mate selection is to a surpris-
ing extent random and unpredictable. Although this is perhaps
disconcerting to psychologists, this conclusion will come as no
surprise to poets, parents, and siblings. We suggest an explana-
tion of these findings based on evolutionary considerations.
Study 1: The Similarity Model of Mate Selection
The simplest hypothesis about mate selection is that of posi-
tive assortative mating, the conjecture that we choose mates
who are like ourselves in cognitive ability, personality, interests,
values, attitudes, and so on. A related model, negative assort-
ment or complementary selection (“opposites attract”), can be
tested at the same time with thd same data. With remarkable
consistency, spousal correlations have been shown to be posi-
tive although relatively small (Buss, 1984; Vandenberg, 1972).
Modest positive spousal correlations have been reported for
anthropometric variables (rs = . 10 to .30; Plomin, DeFries, &
Roberts, 1977) and for IQ (r = .37; Bouchard &. McGue, 1981);
somewhat stronger ones have been reported for physical attrac-
tivenesses= .38 to .52; Murstein, 1972; White, 1980) and educa-
tional attainment (r = .46; Plomin, DeFries, & Roberts, 1977).
Spousal similarity in personality, measured by self-report or
other rated, is weak, with correlations ranging from —.23 to .47
but averaging about . 15 (Buss, 1984), whereas correlations for
personal values are slightly higher (rs = .20 to .58; Caspi, Her-
bener, & Ozer, 1992; Jensen, 1978). Similar correlations have
been reported also for the unwed biological parents of adopted
Journal of Personality and Social Psychology, 1993, Vol. 65. No. 1,56-68
Copyright 1993 by the American Psychological Association, Inc. 0022-3514∕93∕J3.00
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