Chapter 14 The Major Motives of Life: Food, Love, Sex, and work 491These findings have inspired some oversim-
plifiers to call oxytocin the “love” or “cuddle”
hormone, or even “liquid trust.” Cute, but if it
really is such a spur to love and attachment, why
are humans fighting so much? It turns out that
giving people doses of oxytocin makes them more
likely to favor their own group over other groups,
and increases defensive aggression against outsid-
ers (De Dreu et al., 2011). So perhaps oxytocin
is the “cuddle your own kind and the hell with
the rest of you” hormone. Moreover, high levels
of oxytocin in women and of vasopressin in men
are actually biological markers of relationship dis-
tress (Taylor, Saphire-Bernstein, & Seeman, 2010).
Finally, people’s love
and attachment his-
tories affect how they
respond to oxytocin
as well as the other
way around; this is
why giving oxytocin
to people with at-
tachment problems often backfires, making them
even more distrustful (Miller, 2013). For example,
after inhaling oxytocin, men who had had good
attachments to their mothers remembered them as
being unusually caring and supportive, compared
to men with similar attachments who received a
placebo. But men who had troubled early home
lives remembered their mothers as being much less
caring than did similar men who got the placebo
(Bartz et al., 2010).
Some of the characteristic feelings and ac-
tions that occur during attachment are mediated
by reward circuits in the brain that involve the
release of endorphins, the brain’s natural opiates.
When baby mice and other animals are separated
from their mothers, they cry out in distress, and
the mother’s touch (or lick) releases endorphins
that soothe the infant. But when puppies, guinea
pigs, and chicks are injected with low doses ofpartner’s scent can turn you on (or off). Physical
cues in a potential partner’s voice and body shape,
and even in how similar his or her face is to yours,
may attract or repel you. You may be exhilarated
by the same rewarding dopamine jolt that makes
anticipation of a fabulous meal or an addictive
drug so pleasurable, and you may be aroused
by an increase in adrenaline (Aron et al., 2005;
Cozolino, 2006). Eventually, hormones become
involved in the longer-lasting phase of attachment
and bonding.
The neurological origins of passionate love
may begin in infancy, in the baby’s attachment to
the mother. In the view of evolutionary psycholo-
gists, maternal and romantic love, the deepest
of human attachments, share a common evolu-
tionary purpose—preserving the species—and so
they share common neural mechanisms, the ones
that make attachment and pair-bonding feel good.
Key neurotransmitters and hormones that are
involved in pleasure and reward are activated in
the mother–baby pair-bond and again later in the
pair-bond of adult lovers (Diamond, 2004).
Two important hormones for social bond-
ing are oxytocin and vasopressin, which are similar
in molecular structure and influence feelings and
expressions of love, caring, and trust not only be-
tween mothers and babies but also between friends
and between lovers (Poulin, Holman, & Buffone,
2012; Walum et al., 2008). In one study, volun-
teers who inhaled oxytocin in a nasal spray were
later more likely than control subjects to trust one
another in various risky interactions (Kosfeld et
al., 2005). In another study, couples given oxyto-
cin increased their nonverbal expressions of love
for one another—gazing, smiling, and touching—
compared with couples given a placebo (Gonzaga
et al., 2006). Conversely, when prairie voles, a
monogamous species, are given a drug that blocks
oxytocin, they continue to mate but don’t get at-
tached to their partners (Ross et al., 2009).
The biology of the baby–mother bond may be the origin of adult romantic love, with its exchange of loving gazes and
depth of attachment.
About the “Cuddle
Hormone”Thinking
CriTiCally