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DAVID T. LYKKEN AND AUKE TELLEGEN
husbands of female MZ twins do more often say they liked than
they disliked their wives’ twin sister, although only 13% admit
that they might have fallen for her myself We suggest that these
data merely reflect the well-established tendency of men to
attach more importance to physical appearance.
We cannot of course claim that these data are dispositive.
Mate selection may be based on real or perceived similarities, as
yet undiscovered, that are strong enough to permit the similar-
ity or equity models to account for specific choices. The spouses
of MZ twins may be very similar on variables other than those
that we studied, similar enough to support the idiographic
model of’mate selection. Our interpretation of Studies 3 and 4
assumes the validity of our respondents’ reports of how at-
tracted they were to their cotwins’ mate or to the cotwin of their
own recently selected mate; this assumption may be erroneous.
If we provisionally accept our interpretation of these data, we
are left with a curious and disquieting conclusion: Although
most human choice behavior lawfully reflects the characteris-
tics of the chooser and of the choice, the most important choice
of all, that of a mate, seems to be an exception. Although we do
tend to choose from among people like ourselves, another per-
son who is remarkably like ourselves (our MZ twin) is not likely
to be drawn to the same choice we make. Having made a choice,
when we are then confronted with a second mate candidate
who is remarkably like the person we have chosen, we are not
also strongly attracted to that person. Because these conclu-
sions are surprising, we hope others will find new ways to test
them. Meanwhile, we outline a theory that is compatible with
these interpretations, namely, that human pair bonding is rela-
tively adventitious, based on romantic infatuation which, as
Stendhal observed, “is like a fever that comes and goes quite
independently of the will.”
Pair Bonding
Ah! Sweet mystery of life, at last I’ve found you!
Ah! I know at last the secret of it all!
-Victor Herbert
In a fascinating discussion of the evolution of love, Mellen
(1981) attempted to account for the fact that, unlike our pri-
mate cousins (excepting the solitary gibbon) we are a pair-bond-
ing species. These pairings are not always exclusive nor do the∣'
always endure for life, but pair-bonding is characteristic of our
kind across cultures and since before there were cultures. There-
fore, the fact that pair bonding (sometimes polygynous pair
bonding) is universally supported by cultural institutions at-
tests to its adaptational importance without denying that its
primal roots are in the human genome. And that adaptational
importance, of course, derived from the need for the shared
efforts of a male and female parent to provide for the nutrition
and protection of the uniquely altricial human infant.
The bond to which Mellen refers, the capacity for which
evolved during the Plio-Pleistocene, motivated those ancestral
fathers to stand between their families and danger and to trek
home from hunting expeditions carrying heavy loads of meat
instead of merely consuming their fill on the spot. And these
impulses had to be sustained at least through the mate’s preg-
nancy and the early infancy of the offspring of that bond. This
pair bonding that was adaptive during the evolution of our spe-
cies and thus became a species-typical human disposition
should be distinguished from what Berscheid and Walster
(1978), among others, refer to as companionate love, “the affec-
tion we feel for those with whom our lives are deeply inter-
twined” (p. 117). In ancestral times, and often in modern times
as well, companionate love developed after mating or marriage,
and the literature on close relationships (e.g., Drigotas & Rus-
bult, 1992; Hendrick, 1989; Huston, І974; Ickes, 1985; Stern-
berg & Barnes, 1988) is largely concerned with those factors
that determine whether companionate love blossoms or
withers. But companionate love takes time to flower, for mu-
tual adjustments, for the sharing of experiences, for the forging
of the ties that bind. One universal of human culture is the
institution of marriage, which has the effect (and was presum-
ably designed for this effect) of providing the time for pair
bonding to mature into a more stable companionate relation-
ship.
But it is necessary to ask What effected this'result during the
Pleistocene? What served to bind the mated pair together until
the glue was set? It seems appropriate to invoke the concept of
infatuation or romantic love (e.g., Walster& Walster, 1978). The
time course of romantic love is opposite to that of Companion-
ate affection, the first peaking early and then tending to subside
while the second more gradually matures. Young lovers gener-
ally feel an intense and exclusive commitment to one particular
beloved, often after only months or even weeks of acquain-
tance. Berscheid and Campbell (198 1) described the state of the
young lover as one “of heightened and intensified positive emo-
tional experiences perhaps unmatched by any other period in
most people’s lives” (p. 227).
Some empirical support for this characterization of the early
stages of romantic love can be found in the responses of
hundreds of young lovers to whom Hendrick and Hendrick
(1986) administered a 42-item Love Attitudes Scale. Among the
items most strongly endorsed by these subjects were “My lover
and I have the right physical ‘chemistry’ between us”; “I feel that
my lover and I were meant for each other”; and “My lover fits
my ideal standards of physical beauty/handsomeness” (their
Table 1, p. 395). Among the students studied by Hazan and
Shaver (1987), some 85% rejected the statement, “The kind of
head-over-heels romantic love depicted in novels and movies
doesn’t exist in real life” (their Table 7, p. 5 18). Tennov (1979),
who coined the term limerence specifically to distinguish ro-
mantic delirium from the more sober and stable companionate
love that limerence ideally will presage, provided many case
histories illustrating the phenomenon. Tennov also provided
examples of nonlimerent people, both from her researches and
from the literature (e.g., Richard Wagner and Lord Byron): peo-
ple experienced in sexual relationships who yet had never been
“in love.”
If the capacity for companionate love evolved in our species
to enhance the viability of vulnerable hominid young, it seems
reasonable to conclude that the related capacity for romantic
infatuation, which may be specific to our species, evolved con-
currently because it enabled pair bonding. Within broad limits,
it would not have mattered who paired with whom; as long as
the female was young and healthy and the male strong and an
attentive provider, the evolutionarily important goal-the