The Dangerous Passion: Why Jealousy Is as Necessary as Love and Sex (10 page)

But what if you had a choice—experiencing your partner having
sexual intercourse with someone else or becoming emotionally involved with
someone else? This is what I call the “Sophie’s choice” of the jealousy
dilemmas. In the movie
Sophie’s Choice,
the female lead, played by
Meryl Streep, is forced to choose which of her two children will be killed.
Clearly, this dilemma is a horror that no parent should ever face. But when
forced, Sophie indeed makes a choice. This dilemma revealed a preference that
may never have been revealed by any other situation.

The jealousy dilemma is in some ways analogous to “Sophie’s
Choice.” Although having a partner become sexually or emotionally involved with
someone else is a monogamist’s nightmare, men and women can determine which one
would be more upsetting when asked to imagine the dilemma. Here is what we
asked the participants in one study: “Please think of a serious committed
relationship that you have had in the past, that you currently have, or that
you would like to have. Imagine that you discover that the person with whom
you’ve been seriously involved started seeing a former lover. What action would
be
more difficult
for you to
forgive?
(
a
) Your
partner rekindles passionate sexual intercourse with the former lover, or (
b
)
Your partner rekindles a deep emotional attachment to the former lover.” In
this study of 530 men and women, 67 percent of the men reported that they would
find the sexual involvement of their partner more difficult to forgive, whereas
only 44 percent of women reported that the sexual infidelity would be more
difficult to forgive.

Verbal reports are reasonable sources of data, but ideally,
confirming evidence from other types of tests is more convincing for experts
and nonexperts alike, so we brought 60 men and women into our
psycho-physiological laboratory. To evaluate physiological distress from
imagining the two types of infidelity, the experimenters placed electrodes on
the corrugator muscle on the brow of the forehead, which contracts when people
frown. We also attached electrodes on the first and third fingers of the right
hand to measure electrodermal response, or sweating, and on the thumb to
measure pulse or heart rate. Then participants were asked to imagine either a
sexual infidelity (“imagining your partner having sex with someone else . . .
get the feelings and images clearly in mind”) or an emotional infidelity
(“imagining your partner falling in love with someone else . . . get the
feelings and images clearly in mind”). Participants pressed a button when they
had the feelings and images clearly in mind, which activated the physiological
recording devices for the next 20 seconds.

The men became more physiologically distressed by the sexual
infidelity. Their heart rates accelerated by nearly five beats per minute,
which is roughly equivalent to drinking three cups of strong coffee at one
time. Their skin conductance, also an indication of distress, increased with
the thought of sexual infidelity, but showed a smaller change from baseline in
response to the thought of emotional infidelity. And their forehead brow muscle
began to contract accordion-like in response to sexual infidelity, indicating
deep displeasure, as compared with smaller contractions in response to
emotional infidelity. When we observed the men in this condition through a
one-way mirror, many appeared flushed and so obviously upset that we hardly
needed the physiological recording devices to document it.

Women tended to show the opposite pattern. They exhibited
greater physiological distress at the thought of emotional infidelity. Women’s
frowning, for example, increased nearly three times as much in response to a
partner’s emotional infidelity as compared to sexual infidelity. The
convergence of psychological and physiological reactions of distress strongly
confirms the predicted sex difference—men and women may be equally jealous, but
the events that trigger jealousy differ.

Not every psychologist agrees with our interpretation. David
DeSteno and Peter Salovey proposed that men and women differ in their “beliefs”
about sexual and emotional involvement. When a man thinks that his partner is
becoming sexually involved with a rival, for example, he might also think that
his partner will be getting emotionally involved as well—a so-called double
shot of infidelity. The reason men get more upset about sexual rather than
emotional infidelity, they argue, is not because men are really more jealous
about sexual infidelity but because they “believe” that a sexual infidelity
will result in the double shot of infidelity, which includes emotional
infidelity.

Women, they argue, have different beliefs, although DeSteno and
Salovey fail to explain why. Women believe in a reverse double shot, that if their
partner becomes emotionally involved with a rival, he will also become sexually
involved. It’s women’s beliefs about this double shot of infidelity that upsets
them, DeSteno and Salovey argue, and not that women really are more upset about
an emotional betrayal.

Our theory opposes the double-shot theory. Given the large sex
differences stemming from fundamental differences in reproductive biology, it
would be extremely unlikely for selection to have failed to produce
psychological sex differences about the two forms of infidelity. The hard hand
of data usually settles scientific disagreements. So my research collaborators
and I conducted four studies in three different cultures to pit the predictions
from our evolutionary theory against the predictions from the double-shot
hypothesis. One study involved 1,122 participants from a liberal arts college
in the southeastern United States. We asked them to imagine their partner
becoming interested in someone else: “What would upset or distress you more: (
a
)imagining
your partner forming a deep emotional (
but not sexual
) relationship
with that person, or (
b
) imagining your partner enjoying a sexual (
but
not emotional
) relationship with that person?”

Men and women differed by roughly 35 percent in their responses,
as predicted by the evolutionary model. Women continued to express greater
upset about a partner’s emotional infidelity, even if it did not involve sex.
Men continued to show more upset than women about a partner’s sexual
infidelity, even if it did not involve emotional involvement. If the
double-shot hypothesis was the correct explanation for the initial sex
differences that we found, then the sex difference should have disappeared when
we isolated the sexual and emotional components of infidelity. It did not.

In a second study of 234 women and men, we used a different
strategy for pitting the competing hypotheses against each other. We asked
participants to imagine that their worst nightmare had occurred, that their
partner had become both sexually
and
emotionally involved with someone
else. We then asked them to state
which aspect
they found more
upsetting.

The results were conclusive. We found large sex differences
precisely as predicted by our evolutionary theory: 63 percent of the men, but
only 13 percent of the women, found the sexual aspect of the infidelity to be
most upsetting; in contrast, 87 percent of the women, but only 37 percent of
the men, found the emotional aspect of the infidelity to be most upsetting. No
matter how the questions were worded, no matter which method we used, we saw
the same sex difference in every test.

Together with Jae Choe, at Seoul National University, and Mariko
and Toshikazu Hasegawa, at the University of Tokyo, we conducted a final study
on Koreans and Japanese. Choe and the Hasegawas found precisely the same sex
differences: women reported more distress than men when imagining that their
partner was emotionally unfaithful; men reported more distress than women when
imagining a partner having sex with a rival.

Several other scientists have now confirmed our results using
somewhat different methods. In a study of 392 men and women in Sweden, Michael
Wiederman and Erica Kendall of Ball State University posed these dilemmas:
“Please read the following two scenarios and circle the one you would find most
upsetting: (
a
) Your partner recently made friends with a co-worker of
the other gender and has been spending more and more time with that person. You
are sure that the two of them have not had sexual intercourse, but they seem to
like each other very much. The two of them have many things in common and you
suspect that they are falling in love. Or (
b
) You discover that, while
your partner was away on vacation, your partner met someone and had sexual
intercourse once with that person. You are sure that your partner loves you
very much and highly values your relationship together. You also realize that,
even though your partner did have sexual intercourse while on vacation, it was
a ‘one night stand’ and your partner would never see that person again.”

Wiederman and Kendall found that a majority of the Swedish men
(62 percent) found the sexual infidelity of their partners more upsetting,
whereas the majority of the Swedish women (63 percent) found the emotional
infidelity of their partners more upsetting. They concluded that “contrary to
the double-shot explanation, choice of scenario was unrelated to attitudes
regarding whether the other gender was capable of satisfying sexual relations
outside of a love relationship.”

These and similar sex differences have now been replicated in
China, Germany, the Netherlands, Korea, Sweden, and Japan. The Swedish and
Chinese findings are particularly intriguing because they represent cultures at
opposite ends of the spectrum of sexual liberality. Sweden tends to be a
sexually open culture, with high rates of premarital and extramarital sex.
Swedes stress equality between the sexes in most matters, including sexuality.
China, according to David Geary of the University of Missouri-Columbia, strongly
frowns on premarital sex and shows low affair rates. The same basic sex
differences emerge in all these diverse cultures. Men’s jealousy is more
sensitive to cues of sexual infidelity, and women’s jealousy is more sensitive
to cues of emotional infidelity. These cross-cultural findings provide striking
support for the theory that these are universal sex differences. The
double-shot theory cannot explain why these sex differences would be universal.

These basic sex differences also emerge in actual reports of
jealous episodes. We asked several hundred men and women to describe, in their
own words, the details of a specific episode where they experienced jealousy.
The following example is one woman’s description:

“My boyfriend chose to talk about a problem with a female friend
of his instead of me. She happened to be home when he called and I wasn’t. His
friend doesn’t like me and always tells my boyfriend bad things about me. What
triggered my jealousy was just the fact that he chose to talk to her instead of
me . . . it made me so mad! He doesn’t talk about his feelings often, so when
he does it’s a really special experience. I yelled at him because he felt
better after talking to her, and didn’t want to talk more about it, even to me.
I cried because I was really hurt.”

Another woman reported the following episode that triggered her
jealousy:

“My boyfriend got a call from a girl that used to like him not
that long ago and they were talking up a blast. He was laughing and sounded
really interested in what she was saying and cracking jokes with her . . . etc.
The fact that we had not had a conversation like that in a really long time and
we were supposed to hang out that night, and while he was on the phone, I just
sat there waiting for him . . . I yelled at him when he got off and refused to
have sex that night.”

The emotional aspects of the betrayal pervaded women’s
descriptions of the situations that triggered their jealousy. Contrast these
with a man’s description of what triggered his jealousy:

“I had a feeling that my girlfriend was cheating on me. When I
got home one evening, I checked the messages and there was some guy who had
called for her. I looked up the number on our caller ID, and called the guy.
The guy basically admitted that they had been together, having sex. When my
girlfriend came home she confessed. I grilled her about every detail of their
sexual activity. We tried to make it past this explosion, but I could not get
the images out of my mind. I kept picturing her naked underneath this other
guy, trying out sexual positions we had tried. She swore that she loved me and
that it would never happen again, but it tore me up; I couldn’t get the images
out of my head. We split up a few weeks later.”

Men’s sexual jealousy can be triggered even before a full-blown
relationship has formed, as illustrated by the following case:

“I’ve got a smart, cool, attractive neighbor that I’ve been
falling in love with. I had been actively pursuing her for weeks, helped set her
up in her apartment, showed her the town, and had fun with her. Then my [male]
roommate and I had a big party. He is handsome, I can admit, and he ended up
hooking up with [having sex with] the woman I had been falling in love with.
Then, last night, while I was at work, my roomie and my attractive neighbor
cooked dinner, drank a little, smoked a little pot, and wound up having sex
again! The shitty part was that I was wired on caffeine and trying to fall
asleep, and I could hear them kissing in his room because the door was open. I
had actively pursued this girl for weeks, and my roommate spends one fucking
night with her, and bang. I got dressed and left, because when I get jealous I
get really hot and flustered and nauseous. I walked the streets for hours
alone, cursing the way this cookie had crumbled.”