Article

Estrogens and relationship jealousy

Abstract and Figures

The relation between sex hormones and responses to partner infidelity was explored in two studies reported here. The first confirmed the standard sex difference in relationship jealousy, that males (n=133) are relatively more distressed by a partner’s sexual infidelity and females (n=159) by a partner’s emotional infidelity. The study also revealed that females using hormone-based birth control (n=61) tended more toward sexual jealousy than did other females, and reported more intense affective responses to partner infidelity (n=77). In study two, 47 females were assessed four times across one month. Patterns of response to partner infidelity did not vary by week of menstrual cycle, but significant relations between salivary estradiol level and jealousy responses were obtained during the time of rising and high fertility risk. The implications, at least for females, are that any evolved psychological, affective, or behavioral dispositions regarding reproduction-related relationships are potentially moderated by estradiol, and that the use of synthetic hormones may disrupt this relation.
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ESTROGENS AND RELATIONSHIP JEALOUSY
David C. Geary
University of Missouri at Columbia
M. Catherine DeSoto
University of Northern Iowa
Mary K. Hoard, Melanie Skaggs Sheldon, and M. Lynne Cooper
University of Missouri at Columbia
The relation between sex hormones and responses to partner infidelity
was explored in two studies reported here. The first confirmed the stan-
dard sex difference in relationship jealousy, that males (n = 133) are rela-
tively more distressed by a partner's sexual infidelity and females (n=159)
by a partner's emotional infidelity. The study also revealed that females
using hormone-based birth control (n = 61) tended more toward sexual
jealousy than did other females, and reported more intense affective re-
sponses to partner infidelity (n = 77). In study two, 47 females were as-
sessed four times across one month. Patterns of response to partner
infidelity did not vary by week of menstrual cycle, but significant rela-
tions between salivary estradiol level and jealousy responses were ob-
tained during the time of rising and high fertility risk. The implications,
at least for females, are that any evolved psychological, affective, or be-
havioral dispositions regarding reproduction-related relationships are po-
tentially moderated by estradiol, and that the use of synthetic hormones
may disrupt this relation.
KEY WORDS: Infidelity; Relationship jealousy; Sex differences; Sex hormones
Received March 1, 2001; accepted May 16, 200l.
Address all correspondence to: David C. Geary, Department of Psychological Sciences, 210
McAlester Hall, University of Missouri, Columbia, MO 65211-2500. E-mail:
GearyD@Missouri.edu
Copyright 2001 by Walter de Gruyter, Inc., New York
Human Nature, Vol. 12, No.4, pp. 299-320. 1045-6767/01/$1.00+.10
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Human paternal investment and female-female competition over this in-
vestment make human reproductive dynamics unusual, in comparison
with those of other mammalian species (Andersson 1994; Clutton-Brock
1989; Darwin 1871; Geary 2000; Geary and Flinn 2001; Trivers 1972). In ad-
dition to creating a resource over which females compete, human paternal
investment results in extensive costs to males who have been cuckolded
(Daly et al. 1982; Geary 1998). It has been hypothesized that these repro-
ductive dynamics resulted in the evolution of a sex difference in the pattern
of relationship jealousy (Buss et al. 1992; Daly et al. 1982; Symons 1979). To
reduce cuckoldry risk and thus increase the likelihood that parental efforts
will be directed toward one's biological offspring, an evolved sensitivity of
males to a partner's sexual infidelity has been hypothesized. For females, a
partner's emotional infidelity is hypothesized to be relatively more dis-
tressing than his sexual infidelity. This is because maternity is certain and
because a male partner's attentiveness and emotional investment in the re-
lationship are cues to the likelihood that he will maintain the relationship
and invest in any future offspring. If the male develops an emotional at-
tachment to another female, then this is a potential threat to the relation-
ship and thus any future paternal investment.
Empirical studies conducted in the United States, China, and a number
of European nations have generally confirmed these predictions and have
typically been interpreted as support for this evolution-based model (Buss
et al. 1992; Buunk et al. 1996; Geary et al. 1995; Wiederman and Kendall
1999; but see DeSteno and Salovey 1996; Harris 2000; Harris and Christen-
feld 1996). Across all of these studies, males, more so than females, indi-
cate that a partner's sexual infidelity is relatively more distressing than a
partner's emotional infidelity. Females, more so than males, indicate that
a partner's emotional infidelity is more distressing than a partner's sexual
infidelity.
Although the empirical result is well established, several issues remain to be
addressed. First, females who are using hormone-based birth control
do not show the same pattern of sexual behavior and mate preferences as
females who are not using these synthetic hormones (e.g., Chavanne and
Gallup 1998; Gangestad and Thornhill 1998). The implication is that the
use of synthetic hormones may disrupt many of the affective, psychologi-
cal, and behavioral systems that influence the dynamics of reproduction-
related relationships. Because relationship jealousy is an integral part of
the suite of variables that influence reproduction-related relationships, the
possibility that the use of synthetic hormones disrupts naturally occurring
patterns of relationship jealousy needs to be explored. In other words, if fe-
male responses to relationship jealousy covary with the use of synthetic
hormones, then previous studies that have combined---in unknown pro-
portions--- females who are and are not using these hormones may not
Estrogens and Jealousy
301
have provided an accurate assessment of naturally occurring sex differ-
ences in this area. The first study reported here was designed to address
this issue. The second study assessed whether patterns of relationship jeal-
ousy vary across the menstrual cycle, and are related to salivary levels of
estradiol for females who are not taking synthetic hormones.
HORMONE-BASED BIRTH CONTROL
The most common hormone-based birth control method used in the
United States includes synthetic forms of estradiol and progesterone (i.e.,
progestin) administered by means of either oral contraceptive or implant
(Ferin et al. 1993). The biochemical structure of these synthetic hormones
differs from that of human 17-beta estradiol---the estrogen that appears to
be the most biologically active across the menstrual cycle---and proges-
terone, and the sites and mechanisms of biological action may differ as
well. In fact, many forms of progestin are derived from testosterone and
can have androgenic effects. The use of hormone-based birth control thus
has the potential to change females’ psychological and social behavior in
ways that differ from the influence of natural estrogens or progesterone
(e.g., Gangestad and Thomhill,1998).
FEMALE SEXUALITY AND THE MENSTRUAL CYCLE
Females who are not taking hormone-based birth control exhibit, as a
group, systematic changes in cognition, sexual behavior, and mate prefer-
ences during the second week of the menstrual cycle, that is, during the
time of rising and high fertility risk (Bellis and Baker 1990; Chavanne and
Gallup 1998; Gangestad and Thornhill 1998; Kimura 1999; Penton-Voak
and Perrett 2000; Penton-Voak et al. 1999; Thornhill and Gangestad 1999;
Wedekind et al. 1995; Wilcox et al. 2000). Bellis and Baker found that fe-
males who engage in an extra-pair copulation are most likely to do so dur-
ing the time of high fertility risk and are less likely to use a contraceptive
than during copulations with their long-term social partner. The pattern
suggests that the extra-pair copulation may be with a more fit male and
that the long-term partner may be cuckolded if pregnancy occurs.
In keeping with this view, sensitivity to and rated attractiveness of male
pheromones increases during this time as well. Gangestad and Thornhill
(1998) found that the scent of facially symmetric males (as assessed
through scent on their shirts, without the male) was rated as more attrac-
tive and sexy than was the scent of less symmetric males, but only during
the time of rising and high fertility risk (see also Thornhill and Gangestad
Human Nature, Vol. 12, No. 4, 2001
302
1999). Similarly, Penton-Voak and colleagues have found that females rate
masculine faces, those with a more prominent jaw, as more attractive dur-
ing the second week of the menstrual cycle than at other points in the cycle
(Penton-V oak and Perrett 2000; Penton-Voak et al. 1999). Scent, facial sym-
metry, and a masculine jaw bone may, in turn, be proximate cues to male
genetic fitness, including immunocompetence (Folstad and Karter 1992;
Shackelford and Larsen 1997; Wedekind et al. 1995).
This pattern is consistent with the position that females have an evolved
sensitivity to proximate cues of male fitness, but a sensitivity that is only
expressed during times of rising and high fertility risk, that is, during the
second week of the menstrual cycle. The pattern also suggests that female
sexuality can involve a mixed social and reproductive strategy, whereby
the female's social partner---the male providing paternal investment---
may not be the father of her offspring (Bellis and Baker 1990; Gangestad
and Simpson 1990, 2000; Gangestad and Thornhill 1998; Geary 1998). In
this view, females are generally attentive to the relationship with the social
partner and thus maintain his investment (Geary 2000), becoming sensi-
tive to the cues of a more fit male only during the brief period of rising and
high fertility risk. In this way, the risk of her partner detecting cuckoldry
is reduced, given the relatively brief period during which she is attracted
to and potentially sexually responsive to other males.
The systematic changes in female sexual behavior and mate preferences
across the menstrual cycle suggest that females' responses to a partner's
sexual infidelity or emotional infidelity may also vary across the menstrual
cycle and with estradiol levels. One proposal is that during the time of ris-
ing and high fertility risk, females will be especially sensitive to cues that
are predictive of their social partners' continued investment-that is, they
should show more distress in response to a partner's emotional infidelity
(Gaulin et al. 1997). An alternative possibility is that females are more sen-
sitive to sexual cues in general during the time of rising and high fertility
risk and thus might respond more intensely to a partner's sexual infidelity.
The one study that tested this hypothesis did, indeed, find that females
were more likely to report that a partner's emotional infidelity was more
distressing than his sexual infidelity during the time of rising and high fer-
tility risk and the opposite pattern during menstruation (Gaulin et al. 1997).
Gaulin and his colleagues also estimated females' estradiol and proges-
terone levels, based on reported day in menstrual cycle, and found that
estradiol, but not progesterone, estimates were positively correlated with a
tendency toward emotional jealousy. However, this study compared two
groups of females who were at different points in the menstrual cycle,
rather than testing the same females at different points in the cycle. The sec-
ond study described below attempted to replicate this result but with the
use of a within-subjects design, that is, by assessing the same females four
Estrogens and Jealousy
303
times across one month. The second study also extended Gaulin and col-
leagues' research through examination of the relation between females' re-
sponses to partner infidelity and salivary estradiol levels, rather than
estimated estradiol levels based on day in cycle.
STUDY ONE
Sex differences in patterns of distress and reported affective responses to a
partner's sexual or emotional infidelity were assessed in the first study, as
were differences between females taking hormone-based birth control and
those who were not. The latter comparison is important because it is not
known if the use of synthetic estradiol and progestin influences the jeal-
ousy responses of females. As noted, many forms of progestin are derived
from testosterone and could thus result in more male-like responses to
partner infidelity, whereas the elevated levels of synthetic estradiol may
work in the opposite manner.
Subjects
The initial subject pool consisted of 398 general psychology students
from the University of Missouri, but the sample was restricted to the 292
students who reported having had sexual intercourse at least once in their
lifetime. The restriction was imposed to reduce potential differences in the
sexual relationships of females who are taking some form of hormone-
based birth control and those who are not. Of these 292 subjects, 159 were
female and 133 were male. The respective mean ages of the females and
males were 19.1 years (s.d. = 1.0) and 19.6 years (s.d. = 1.5). Owing to re-
stricted variability in the age of the sample, the sex difference was statisti-
cally, though not practically, significant (p < .0001).
Procedure
Assessment measures. All subjects were administered a battery of cogni-
tive and psychological measures. The focus of the current study is on sur-
veys of relationship jealousy, sexual activity, and use of birth control.
The first jealousy item was based on research by Buss and colleagues
(Buss et al. 1992) and asked subjects to "imagine that their most recent sex-
ual partner had become interested in someone else and told you about it
right now. What would distress or upset you more right now?" Subjects
then selected one of the options below:
A. If your partner told you he or she had formed a deep emotional at-
tachment to another person.
Human Nature, Vol. 12, No. 4, 2001
304
B. If your partner told you he or she had passionate sex with another
person.
Following completion of the above item and to obtain a more nuanced
assessment of reactions to partner infidelity, subjects were asked to first
imagine that their partner had developed a deep emotional attachment to
another person and then respond, based on how they would feel today, to
four items that assessed their affective reactions to this scenario (Geary et
al. 1995). For the first item, the subjects rated the relative degree of hurt
feelings or anger on a 5-point scale, ranging from -2 (much more hurt
than angry) to 2 (much more angry than hurt); for the analyses, this item
was rescaled from 1 (much more hurt than angry) to 5 (much more angry
than hurt). For the next three items, the intensity of their hurt feelings,
anger, and jealous feelings, respectively, was rated on a 1 (not hurt/ angry /
jealous) to 5 (extremely hurt/ angry /jea10us) scale. The subjects then com-
pleted the same four items, after imagining their partner having passion-
ate sex with another person.
All subjects were asked to indicate the number of times they had had sex
in the past week and to describe their relationship with the person with
whom they last had sex using one of the following choices: (a) someone you
just met; (b) a casual friend or acquaintance; (c) someone you are dating, but
not seriously; (d) a steady boyfriend or girlfriend/ dating seriously; or (e)
your fiancé/spouse. These items were included as a means to control for the
possibility that responses to the partner infidelity items may be more
strongly related to the nature of the most recent reproduction-related rela-
tionship than to biological sex (i.e., being male or female) or hormone use
per se. The females were also asked to indicate whether or not they were
currently using a form of hormone-based birth control.
Administration. The battery was administered once to each subject, ac-
cording to standard instructions and in groups of up to 50 subjects. The
session took about 1 hour to complete.
Results
Sex differences. There was no sex difference in the proportion of males
(40%) or females (37%) who had had sexual intercourse during the past
week (F(1,268) < 1, p> .50). There was, however, a significant sex difference
in the nature of the relationship with their last sexual partner [χ²(4) = 11.61,
p < .05]. As shown in Table 1, a higher proportion of males reported that
their last sexual relationship was with someone they had just met or with
an acquaintance, whereas a higher proportion of females reported that
their last sexual relationship was with a serious boyfriend or with a fiancé/
spouse.
Estrogens and Jealousy
305
Table 1. Sex Differences in the Nature of Most
Recent Sexual Relationship
Percentage
Nature of Relationship Male Female
Just met 11 4
Acquaintance 19 11
Dating, not serious 12 14
Dating, serious 57 65
Fiancé/ Spouse 2 6
Note: The first column does not total to 100, owing to rounding.
χ² (4) = 11.61, P < .05
As with previous studies, most of the males (73%) indicated that their
partner's sexual infidelity was more distressing than their partner's emo-
tional infidelity, whereas most of the females (63%) indicated the opposite
pattern b:2(1) = 37.36, P < .001]. Mean scores for the reported affective re-
sponses to the imagined emotional and sexual infidelity items are shown
in Table 2. The first item, relative degree of hurt/anger, was submitted to
a 2 (sex) by 2 (infidelity status: emotional or sexual, based on response to
the basic partner infidelity item) analysis of variance (ANOVA). The three
other items (degree of hurt feelings, anger, and jealous feelings) were first
submitted to a 2 (sex) by 2 (infidelity status) multivariate analysis of
Table 2. Sex Differences in Reported Emotional
Reactions to Partner Infidelity
Item
Male
Mean s.d.
Female
Mean s.d.
EMOTIONAL INFIDELITY
Hurt/Anger 2.37 1.12 1.68 0.90
Hurt 3.38 1.36 3.97 1.27
Angry 2.89 1.33 3.15 1.27
Jealous 3.02 1.37 3.52 1.21
SEXUAL INFIDELITY
Hurt/Anger 3.59 1.19 3.32 1.38
Hurt 3.37 1.37 3.92 1.25
Angry 3.64 1.38 4.07 1.16
Jealous 3.20 1.39 3.33 1.37
Note: Hurt/Anger scores range from 1 (Much more hurt than angry) to 5 (Much more angry than
hurt). All other scores range from 1 [Not hurt (angry, jealous) at all] to 5 [Extremely hurt
(angry, jealous)].
Human Nature, Vol. 12, No. 4, 2001
306
variance (MANOVA). Significant effects were followed up with 2 by 2
ANOVAs.
For imagined emotional infidelity, both females and males reported
more intense hurt feelings than anger, but females reported relatively
more intense hurt feelings than did males (F(l,284) = 26.46, p < .0001). For
imagined sexual infidelity, both females and males reported more intense
anger than hurt feelings, with no sex difference in this respect (F(l,287) =
2.62, p >.10). The MANOVAs revealed a significant main effect for sex for
both imagined emotional infidelity (F(3, 282) = 4.11, p < .01) and imagined
sexual infidelity (F(3,283) = 6.42, p < .001), but the main effects for infidelity
status and the sex by infidelity status interactions were not significant (p
values>.05). Follow-up ANOVAs revealed that in response to imagined
emotional infidelity, females reported more intense hurt feelings (F(l,284)
= 9.68, p < .01) and jealous feelings (F(l,284) = 8.05, p < .01) than did males.
In response to imagined sexual infidelity, females reported more intense
hurt feelings (F(l,285) = 16.18, p < .0001) and anger (F(l,285) = 9.80, p < .01)
than did males.
Relationship commitment. Because the nature of the last sexual relation-
ship varied from "just met" to "fiancé/spouse," it could be determined
if jealousy reactions differed with respect to the degree of relationship
commitment.
Infidelity status (i.e., emotional versus sexual) was not related to the na-
ture of the last sexual relationship for either males [χ² (4) = 6.56, p> .10]
or females [χ²(4) = 4.99, p > .25]. The same pattern was found when
this variable was dichotomized into uncommitted ("just met," "acquain-
tance," "dating, not serious") versus committed ("dating serious," "fi-
ancé/spouse") relationships: males [χ² (1) 2.19, p > .10], females [χ² (1) <1,
p> .25].
However, responses to the affective intensity items were correlated with
the nature of last sexual relationship; the latter was coded as a continuous
variable in terms of degree of commitment [1 (just met) to 5 (fiancé/
spouse)]. The nature of this relationship was significantly correlated with
seven of the eight imagined infidelity items and the same pattern of corre-
lations was evident for both males and females (thus the male and female
samples were combined). For their partner's imagined emotional infidelity,
being in a more committed relationship was associated with feeling rela-
tively more hurt than anger (r(255) = - .21, p < .001) and with more intense
overall levels of hurt feelings (r(257) = .45, p < .001), anger (r(257) = .25, p <
.001), and jealous feelings (r(257) = .33, P < .001). For their partner's imag-
ined sexual infidelity, being in a more committed relationship was not cor-
related with degree of hurt/anger (r(257) = - .01, p > .50) but was associated
with more intense overall levels of hurt feelings (r(257) = .44, p < .001), anger
(r(257) = .38, p < .001), and jealous feelings (r(257) = .25, p < .001).
Estrogens and Jealousy
307
Finally, to determine if the sex difference in the nature of the last rela-
tionship was related to the sex differences in intensity of affective re-
sponses to partner infidelity, all of the significant effects described in the
previous section were reanalyzed using the last relationship variable as a
covariate (i.e., in an analysis of covariance, ANCOVA). The results re-
vealed that all of these effects remained significant (p values <.05), with
one exception. For imagined sexual infidelity, the sex difference in terms
of intensity of reported anger no longer reached the conventional sig-
nificance level, although the effect was close to this level (F(I,254) = 3.73,
p = .055).
Hormone status. Of the 159 females, 61 indicated the use of some form of
hormone-based birth control, 77 reported that they did not use this form
of birth control, and the remaining subjects did not respond to this item
and were thus excluded from the subsequent analyses.
A higher proportion of females using hormone-based birth control re-
ported a sexual relationship during the past week (48%) than did females
not using hormone-based birth control (23%) (F(1,123) = 9.23, p < .01). As
shown in Table 3, a higher percentage of females not using hormone-based
birth control reported that their last sexual relationship was with someone
they had just met or with an acquaintance, whereas a higher percentage of
females using hormone-based birth control reported that their last sexual
relationship was with a serious boyfriend [χ² (4) = 12.44, p < .05].
Response to the infidelity item varied with use or lack of hormone-based
birth control, although the difference did not reach the conventional sig-
nificant level [χ² (1) = 3.05, p = .08; Φ= .15]. The majority (70%) of females not
using hormone-based birth control indicated that the emotional infidelity
of their partner was more distressing than their partner's sexual infidelity,
whereas only about one-half (56%) of the females using a hormone-based
birth control responded in the same way.
Table 3. Hormone-Status Differences in the Nature of
Most Recent Sexual Relationship
Percentage
Nature of Relationship Hormone No Hormone
Just met 0 8
Acquaintance 3 13
Dating, not serious 15 17
Dating, serious 78 53
Fiancé/ Spouse 3 8
Note: Columns do not total to 100, owing to rounding.
χ² (4) = 12.44, p < .05
Human Nature, Vol. 12, No. 4, 2001
308
Table 4. Differences in Reported Emotional Reactions to
Partner Infidelity across Birth-control Status
Hormone No Hormone
Item Mean s.d. Mean s.d.
EMOTIONAL INFIDELITY
Hurt/Anger 1.58 0.77 1.73 0.99
Hurt 4.39 1.04 3.62 1.35
Angry 3.39 1.04 2.91 1.31
Jealous 3.90 1.04 3.32 1.25
SEXUAL INFIDELITY
Hurt/Anger 3.30 1.45 3.43 1.35
Hurt 4.30 1.07 3.57 1.34
Angry 4.36 1.00 3.84 1.25
Jealous 3.72 1.20 3.04 1.43
Note: Hurt/Anger scores range from 1 (Much more hurt than
angry) to 5 (Much more angry than hurt). All other scores range
from 1 [Not hurt (angry, jealous) at all] to 5 [Extremely hurt
(angry, jealous)].
Mean scores among females for the reported affective responses to the
imagined emotional and sexual infidelity items are shown in Table 4. As
with the sex differences analyses, the relative hurt/anger items were ana-
lyzed by means of a 2 (hormone status) by 2 (infidelity status) ANOVA,
and the remaining items by means of a 2 (hormone status) by 2 (infidelity
status) MANOVA. There were no significant main effects or interactions
for the relative hurt/anger items (p values > .10). For imagined emotional
infidelity, the MANOV A reveal significant main effects for hormone status
[F(3,129) = 4.94, p < .01] and infidelity status [F(3,129) = 4.33, p < .01], but a
nonsignificant interaction [F(3,129) = 2.37, p > .05]. For imagined sexual in-
fidelity, the main effect for hormone status was significant [F(3,130) = 4.12,
p < .01], but infidelity status [F(3,130) < 1] and the interaction [F(3,130) < 1]
were not.
For imagined emotional infidelity, follow-up ANOVAs revealed that fe-
males using hormone-based birth control reported more intense hurt feel-
ings [F(1,131) = 14.60, p<.001], anger [F(1,131) = 9.72, p < .01], and jealous
feelings [F(1,131) = 6.97, p < .01] than did females not using hormone-
based birth control. The same pattern was found for imagined sexual infi-
delity: hurt feelings [F(1,132) = 10.48, p < .01], anger [F(1,132) = 5.87,
p < .05], and jealous feelings [F(1,132) = 8.66, P < .01]. For imagined emo-
tional infidelity, the significant main effect for infidelity status was because
of emotionally jealous females, regardless of hormone status, reporting
more intense hurt feelings [F(1,131) = 4.96, p < .05] and anger [F(1,132) =
13.03, p < .001] than sexually jealous females.
Estrogens and Jealousy
309
Finally, because sexual activity during the previous week and the nature
of the last sexual relationship varied with hormone status, all of the sig-
nificant hormone-status effects were reanalyzed using the sexual activity
and sexual relationship variables as covariates. The results revealed that
three of the six hormone-status effects were now nonsignificant (p values
> .10): intensity of anger and jealous feelings for imagined emotional infi-
delity, and intensity of anger for imagined sexual infidelity. Females using
hormone-based birth control still reported more intense hurt feelings for
imagined emotional infidelity [F(l,113) = 5.86, p < .05] and for imagined
sexual infidelity [F(l,113) = 4.20, p < .05]. Females using hormone-based
birth control also reported more intense jealous feelings in response to
imagined sexual infidelity, but the effect did not quite reach the conven-
tional significance level [F(l,113) = 3.646, p = .059].
Reexamining the sex differences. Because use of hormone-based birth con-
trol covaried with responses to several infidelity items, the sex differences
analyses were redone, comparing males with females who were not using
hormone-based birth control. As with the initial analysis, the majority of
males (73%) indicated that their partner's sexual infidelity was more dis-
tressing than their partner's emotional infidelity, whereas the majority of
females (70%) indicated the opposite pattern [χ² (1) = 36.93, p< .001].
However, nearly all of the significant sex differences in affective re-
sponses to imagined partner infidelity were no longer significant. For rel-
ative degree of hurt/ anger, females reported relatively more intense hurt
feelings than did males for imagined emotional infidelity [F(l,204) = 15.76,
p < .0001], but not for imagined sexual infidelity [F(l,205) < 1]. The
MANOVA for imagined sexual infidelity revealed nonsignificant effects
for sex [F(3,201) = 2.07, p > .10], infidelity status [F(3,201) < 1], and the in-
teraction [F(3,201) < 1]. The MANOVA for imagined emotional infidelity
revealed nonsignificant main effects for sex [F(3,200) = 1.83, p > .10] and in-
fidelity status [F(3,200) = 2.12, p > .05], but the interaction was significant
[F(3,200) = 4.86, p < .01]. Follow-up ANOVAs revealed a significant inter-
action for reported intensity of anger [F(l,202) = 9.78, p < .01]. Emotionally
jealous females reported more intense anger (mean = 3.25, s.d. = 1.16) to
imagined emotional infidelity than did sexually jealous females (mean =
2.13, s.d. = 1.29) [F(l,72) = 13.84, p < .001], but no such difference was found
for males [F(l,130) < 1].
Discussion
The standard sex difference in relative distress to a partner's sexual or
emotional infidelity was replicated (e.g., Buss et al. 1992). The initial sex
differences analysis also indicated that females reported more intense
affective responses to partner infidelity, emotional and sexual, than did
Human Nature, Vol. 12, No. 4, 2001
310
males. However, nearly all of the sex differences in reported affective
intensity disappeared when males were compared with females who were
not using hormone-based birth control. The one effect that remained ro-
bust was the standard sex difference, that is, the tendency of males to be
relatively more distressed by their partner's sexual infidelity and females
to be relatively more distressed by their partner's emotional infidelity. In
any case, whether the infidelity was emotional or sexual, in comparison
with infidelity of a casual partner, both males and females reported more
intense affective distress to a committed partner's infidelity. In other
words, even with a sex difference in relative distress to a partner's sexual
or emotional infidelity, females and males were similar in that the inten-
sity of affective responses to partner infidelity varied directly with the de-
gree of relationship commitment to that partner, whether the infidelity
was emotional or sexual.
Jealousy patterns and intensity of affective responses to partner infidelity
also varied across the groups of females who were and were not using syn-
thetic hormones as a form of birth control. For all significant effects, females
using synthetic hormones reported more intense affective responses than
did other females, and many of these effects remained significant when
sexual activity levels and nature of the last sexual relationship were statis-
tically controlled. Moreover, in comparison with other females, a larger
proportion of females using synthetic hormones indicated that the sexual
infidelity of their most recent partner was more distressing than their part-
ner's emotional infidelity. Even though the latter result did not reach con-
ventional levels of significance, it is consistent, when combined with the
affective differences, with the more general finding that use of birth control
disrupts behaviors associated with reproduction-related relationships
(e.g., Gangestad and Thornhill 1998). Future work will be needed to explore
the relation between use of synthetic hormones and the dynamics of
reproduction-related relationships. For instance, does the use of progestin
result in a more masculine pattern of relationship jealousy? Do the differ-
ent types of synthetic birth control result in different patterns of response to
partner infidelity?
For now, the implication is that combining females who are and are not
using hormone-based birth control may lead to an underestimation of the
sex difference in relative distress to a partner's sexual or emotional infi-
delity, and may lead to an overestimation of the magnitude of the sex dif-
ference in intensity of affective responses to infidelity.
STUDY TWO
The goal of the second study was to explore further the potential relation
between sex hormones and relationship jealousy and to do so with an at-
Estrogens and Jealousy
311
tempt to replicate two of Gaulin and colleagues' findings (1997): that fe-
males show more distress to a partner's emotional infidelity at the time of
rising and high fertility risk than during menstruation, and that high lev-
els of estradiol are associated with a tendency toward emotional jealousy.
The current study differed in two important respects from that of Gaulin
and his colleagues. First, a within-subjects rather than a between-subjects
design was used in the current research. In this way, the same females
were compared across a single menstrual cycle, as contrasted with Gaulin
et al.'s comparison of two groups of females who were at different points
in their cycle. Second, rather than estimating estradiol levels based on day
in cycle, salivary estradiol levels were assessed and correlated with female
responses to partner infidelity. If the hypothesis offered by Gaulin and col-
leagues is correct, then high estradiol levels should be positively related to
a bias toward emotional, as contrasted with sexual, jealousy.
Subjects
The subjects were 57 female general psychology students from the Uni-
versity of Missouri who reported themselves to be menstruating regularly
and were not using any form of hormone-based birth control. Potential
subjects were identified through their responses to a pre-testing question-
naire administered to all students enrolled in general psychology at the
university. Females who met the selection criteria were contacted by
means of electronic mail and invited to participate in the study. To increase
sample size, the study one constraint of having had sexual intercourse at
least once in their lifetime was removed.
Of these 57 females, five were not included in the analyses because after
beginning the study they either reported irregularities in their menstrual
cycles (which could indicate pregnancy) or they missed more than one
testing session. Five additional subjects were discarded because they did
not provide sufficient saliva for assay for two or more sessions. The re-
maining 47 subjects attended at least three testing sessions and provided
at least three usable saliva samples. Of these, 31 provided usable samples
for all four testing sessions and 16 provided usable samples for three ses-
sions. Because the missing data for these 16 subjects were distributed across
the four sessions, the degrees of freedom differ across some of the
analyses reported below. Of the 47 subjects, 16 reported that they had
never had sexual intercourse. These subjects were instructed to respond to
items in terms of their most recent committed relationship.
Procedure
Assessment measures. The same battery of measures used in the first study
was administered. The following analyses focused on the same items and
responses to a menstrual cycle questionnaire. The questionnaire included
Human Nature, Vol. 12, No. 4, 2001
312
items on length of cycle (average number of days), regularity of cycle
length, and number of days since the first day of their last menstrual pe-
riod (calendars were provided to facilitate the answering of these items).
Administration. The subjects were tested in groups of no more than 20. As
each subject arrived, she was asked to be seated at a designated place,
which had the materials for saliva collection and the battery of measures.
Subjects were read standardized directions and the order of question-
naires and timing of saliva collection was kept uniform across all sessions.
For the saliva collection, participants removed any gum and rinsed their
mouths with water before beginning the testing session. After 20 minutes,
subjects were asked to stop filling out the questionnaires and saliva col-
lection began. Subjects were instructed to salivate into a polypropelene
funnel connected to a cryovial. The cryovials were premarked with the
participant's subject number. The sample was unstimulated and the par-
ticipants allowed all saliva to be collected without interruption for a pe-
riod of three minutes. During the saliva collection, and in order to facilitate
salivation, subjects were invited to imagine something good to eat or to
imagine the smell of something good to eat. Samples were frozen within
the hour.
Estradiol assay. All samples were assayed by an independent laboratory
(Salimetrics, State College, PA) for salivary estradiol using a double anti-
body radioimmunoassay developed at the Penn State Behavioral En-
docrinology Laboratory (see Shirtcliff et al. 2000). Shirtcliff and colleagues
found that salivary and plasma estradiol levels were significantly corre-
lated (r = .60) and that independent assays of the same salivary sample
yielded estradiol values that varied between 6.5 and 9%. The same proce-
dure described by Shirtcliff et al. was used for the current study.
Saliva samples were thawed, vortexed, and centrifuged at 1,500x g for
twenty minutes. Three hundred microliters of the samples was pipetted
into the appropriate tubes. One hundred microliters of antiserum dilution
was added to all tubes. All tubes were then vortexed and incubated for
four hours at room temperature. One hundred microliters of the x3 estra-
diol [125I] tracer dilution was added to all tubes. Tubes were again vor-
texed and incubated overnight at 4°c. Afterwards, 500 J.lI of precipitating
reagent was added to all tubes. All tubes were then vortexed and incu-
bated for 20 minutes at room temperature. Finally, the tubes were cen-
trifuged at 1,500x g for 20 minutes at room temperature, aspirated or
decanted, and counted for two minutes on a counter (LKB Clinigamma).
Data alignment. To enable the assessment of week in cycle effects, sub-
jects’ data were aligned based on time in cycle. The subjects provided up
to four estimates, one for each testing session, for the number of days since
Estrogens and Jealousy
313
the first day of their last menstrual period. It was assumed that the small-
est of these values was the most accurate, as this represents the shortest lag
between the beginning of the subject's most recent menstrual period and
a testing session. The associated testing session was designated as cycle
week one, the following session as week two, and so forth. If the smallest
value was provided for the fourth testing session, then this session was
designated as week one, and the first session (which should correspond to
the second week of their previous cycle) as week two.
Results
Cycle alignment. Across sessions (unaligned time of measurement), the
mean estimate for subjects' length of cycle ranged between 28.0 (s.d. = 5.8)
and 28.9 (s.d. = 3.0) days; estimates did not vary across sessions [F(3,l11) =
1.47, P > .10]. The mean numbers of reported days since the first day of the
last menses are shown in Table 5 for session and week in cycle (aligned). A
repeated measures ANOV A confirmed that days since last menstrual cycle
did not vary across sessions [F(3,117) = 1.79, p > .10] but did vary across
cycle weeks [F(3,117) = 430.35, p < .001]. Moreover, the means for cycle
weeks show a pattern consistent with the alignment objective, that is, to
assess subjects during week one of the cycle, week two of the cycle, and so
forth.
As can be seen in two righthand columns of Table 5, estradiol levels
(pg/ml) show the same pattern, that is, no variation across sessions
[F(3,96) = 2.40, p > .05], and significant changes across cycle weeks
[F(3,102) = 14.56, p < .001].1 The pattern across cycle weeks is generally
consistent with typical estradiol fluctuations, that is, low levels early in the
Table 5. Day in Menstrual Cycle and Estradiol Levels
Day Since
Beginning of Cycle
Estradiol Levels
(pg/ml)
Time Mean s.d. Mean s.d.
WEEK IN CYCLE
Week 1 5 3 0.30 0.36
Week 2 12 4 0.61 0.53
Week 3 18 5 0.78 0.58
Week 4 26 6 0.68 0.49
TIME OF MEASUREMENT
Session 1 16 10 0.63 0.55
Session 2 13 8 0.54 0.49
Session 3 14 9 0.57 0.54
Session 4 17 9 0.66 0.49
Human Nature, Vol. 12, No. 4, 2001
314
cycle, which then rise and finally decline toward the end of the cycle (e.g.,
Ferin et al. 1993; Laessle et al. 1990). Day in cycle means and standard de-
viations for week two and week three suggest that for many subjects, peak
estradiol levels would have likely occurred between the cycle week two
and cycle week three assessments (Ferin et al. 1993). Still, for most of the
subjects, cycle week two will represent the follicular phase of the cycle,
that is, the time of rising and high fertility risk.
Cycle, sex, and jealousy. Across weeks, between 58% and 63% of the sub-
jects reported that a partner's emotional infidelity was more distressing
than his sexual infidelity, a pattern that did not differ across cycle weeks
[χ² (3) < 1, p > .50]. Mean scores across cycle weeks for responses to the
imagined emotional and sexual infidelity items are shown in Table 6.²
These scores were subjected to repeated measures ANOVAs, which re-
vealed only one significant cycle effect: reported intensity of anger in re-
sponse to a partner's imagined sexual infidelity [F(3,105) = 2.72, p < .05].
However, given the multiple ANOVAs, and an inconsistent pattern across
cycle weeks, this one effect is not considered further.
Estradiol, sex, and jealousy. The relation between estradiol levels and re-
sponses to the partner infidelity items was assessed by means of a repeated
measures ANOVA. In the first analysis, responses to the basic infidelity
item, across each of the four weeks, served as the within-subjects factor, and
estradiol level for each of the four weeks served as the independent vari-
ables. The results revealed a significant effect for the week two estradiol
variable [F(1,25) = 4.89, p < .05], but nonsignificant effects for the week one
Table 6. Differences in Reported Emotional Reactions to Partner Infidelity across
Cycle Week
Week 1 Week 2 Week 3 Week 4
Item Mean s.d. Mean s.d. Mean s.d. Mean s.d.
EMOTIONAL
INFIDELITY
Hurt/Anger 1.94 0.93 1.80 0.98 1.85 1.00 2.00 1.11
Hurt 4.03 1.07 4.13 1.08 4.12 0.82 3.93 1.23
Angry 3.15 1.23 2.97 1.11 3.09 1.01 3.20 1.27
Jealous 3.79 1.14 3.67 1.20 3.73 1.04 3.57 1.22
SEXUAL
INFIDELITY
Hurt/Anger 3.76 1.00 3.57 1.11 3.76 1.01 3.68 1.06
Hurt 3.64 1.17 3.67 1.14 3.88 1.11 3.78 1.11
Angry 4.24 0.93 3.87 1.29 4.00 1.10 4.22 1.01
Jealous 3.58 1.23 3.59 1.27 3.67 1.22 3.63 1.35
Note: Hurt/Anger scores range from 1 (Much more hurt than angry) to 5 (Much more angry than hurt). All
other scores range from 1 [Not hurt (angry, jealous) at all] to 5 [Extremely hurt (angry, jealous)].
Estrogens and Jealousy
315
[F(1,25) = 1.84, p > .10], week three [F(1,25) = 1.65, p > .10], and week four
[F(1,25) < 1] estradiol variables. The within-subjects effect of week (i.e.,
changes in infidelity response across weeks) and the interactions between
week and the estradiol variables were nonsignificant (p values> .20). Fol-
low-up analyses indicated that higher week two estradiol levels were as-
sociated with a greater tendency toward sexual, as contrasted with emotional,
jealousy during cycle week two [F(1,30) = 4.37, p < .05] and cycle
week three [F(1,29) = 4.21, p < .05]. The follow-up analyses included the
estradiol variables for weeks one, three, and four and thus the week two ef-
fects are estimated while controlling for estradiol levels at all other weeks.
The same analytic technique was used to assess the relation between the
estradiol variables and affective responses to the imagined emotional and
sexual infidelity of a partner. The results revealed significant main effects
for the cycle week two estradiol variable for relative degree of hurt/ anger
in response to a partner's imagined emotional [F(1,26) = 7.91, p < .01] and
sexual [F(1,26) = 7.34, p < .05] infidelity, as well as a significant effect for the
cycle week one estradiol variable for hurt/anger in response to imagined
emotional infidelity [F(1,26) = 5.29, p < .05]. Follow-up analyses indicated
that high week two estradiol levels were related to relatively more anger
than hurt in response to a partner's emotional infidelity as reported dur-
ing cycle weeks two and four, and to relatively more hurt than anger in re-
sponse to a partner's sexual infidelity as reported during weeks two and
four (p values < .05). Follow-up analyses also revealed that high week one
estradiol levels were associated with relatively more hurt than anger in re-
sponse to partner's imagined emotional infidelity as reported during cycle
weeks two and four.
Finally, there were no significant within-week correlations between the
estradiol variable and the reported frequency of sexual activity or the sex-
ual relationship variable (r values - .27 to .10, p values> .10).
Discussion
For each of the four cycle weeks, the majority of females reported that
the emotional infidelity of their partner was relatively more distressing
than his sexual infidelity, that is, jealousy status did not vary across cycle
week. Moreover, there was no consistent pattern in the intensity of affec-
tive responses to a partner's imagined sexual or emotional infidelity
across cycle weeks. The set of findings did not confirm the results of
Gaulin and colleagues (1997). The different methods used in Gaulin and
colleagues' study (a between-subjects design) and the current study (a
within-subjects design) may account for the different findings; a resolution
must await future research.
In any case, the most interesting result is the finding of a consistent re-
lation between salivary estradiol levels and jealousy responses during
Human Nature, Vol. 12, No. 4, 2001
316
cycle week two, a relation that held when estradiol levels for the three
other cycle weeks were statistically controlled. Females with a high ab-
solute levels of estradiol during cycle week two tended to report more dis-
tress to a partner's imagined sexual infidelity than to his emotional
infidelity during this week and the following week (i.e., week three), a
finding that is the opposite of that reported by Gaulin et al. (1997). Females
with high week two estradiol levels also reported relatively more anger
than hurt, and less intense hurt feelings, in response to a partner's emo-
tional infidelity, but relatively more hurt than anger in response to a part-
ner's sexual infidelity. Cycle week one estradiol levels were also related to
responses to the hurt/anger item for imagined emotional infidelity, but
week one estradiol levels were not related to responses on the basic infi-
delity item (i.e., tendency toward emotional or sexual jealousy). At this
time, a strong interpretation of the specific pattern of relation between
cycle week two estradiol levels and responses to the infidelity items is
probably premature, in the absence of a replication and given the differ-
ences between this study and that of Gaulin and colleagues (1997).
Nonetheless, it appears that estradiol levels during the time of rising
and high fertility risk---even when controlling for estradiol levels at other
times in the cycle---may result in some changes in the intensity of affective
responses to partner infidelity and may bias females toward greater sensi-
tivity to a partner's potential sexual infidelity. However, the latter re-
sponse may be related to heightened sexual interest during this time in the
cycle, rather than to a change in bias toward one type of partner infidelity
or the other (Harris 2000; Wood 1994). Either way, the finding of a consis-
tent relation between week two estradiol levels and responses to partner
infidelity is consistent with previous findings of changes in female sexual
behavior and mate preferences during this time (Bellis and Baker 1990;
Gangestad and Thornhill 1998; Penton-Voak and Perrett 2000; Penton-
Voak et al. 1999; Thornhill and Gangestad 1999). It appears that patterns of
sexual and relationship jealousy can be added to the suite of psychologi-
cal and sexual behavior changes that occur during the time of rising and
high fertility risk for females.
CONCLUSION
The current research adds to the literature on relationship jealousy in sev-
eral ways. The most interesting and potentially important findings were
that female responses to partner infidelity appear to covary with the use
or lack of synthetic hormones and with naturally occurring changes in
estradiol. The finding that females using hormone-based birth control
were more prone than other females to sexual than emotional jealousy and
Estrogens and Jealousy
317
reported more intense affective responses to partner infidelity has impli-
cations for the interpretation of previous research in this area and for fu-
ture studies. With respect to previous studies, the standard practice of
combining groups of females who are using hormone-based birth control
with those who are not may have resulted in an underestimation of the
magnitude of the sex difference in tendency toward sexual or emotional
jealousy, and an overestimation of the sex difference in intensity of affec-
tive responses to partner infidelity. The results also indicate that in future
studies, investigators should ascertain whether or not female subjects are
using hormone-based birth control and assess whether or not patterns of
relationship jealousy, and many other reproduction-related constructs, co-
vary with hormone use. Further research will also be needed to determine
if different forms of hormone-based birth control (e.g., those that include
synthetic estradiol versus those that do not) are differentially related to re-
sponses to partner infidelity.
The second study reported here was the first to use a within-subjects de-
sign to assess the relation between week in menstrual cycle, estradiol lev-
els, and patterns of response to imagined partner infidelity. The most
intriguing result was that responses to partner infidelity were related to
estradiol levels and primarily, although not entirely, during the time of ris-
ing and high fertility risk, a pattern that is in keeping with studies of fe-
male sexual behavior and mate preferences (Bellis and Baker 1990;
Chavanne and Gallup 1998; Gangestad and Thornhill 1998; Penton-Voak
and Perrett 2000; Penton-Voak et al. 1999; Thornhill and Gangestad 1999;
Wedekind et al. 1995). It appears that during the time of rising and high
fertility risk, high estradiol levels are associated with changes in relative
degree of hurt/anger to different forms of partner infidelity (i.e., emo-
tional or sexual), and to "a tendency toward greater distress over a part-
ner's sexual infidelity than emotional infidelity.
The pattern across studies suggests that for females the expression of
any evolved psychological, emotional, or behavioral dispositions regard-
ing issues of sexuality and relationships is potentially moderated by estra-
diol levels, and that the use of synthetic hormones may disrupt this
relation. Of course, the former pattern may have resulted from other hor-
monal changes (e.g., ratio of estradiol/progesterone), but it is of sufficient
interest to merit further research in this area, as well as to merit studies of
the potential relation between estradiol levels and changes in female mate
preferences across the menstrual cycle.
We thank Mark Flinn for his advice on salivary collection and Leslie Byington,
Maggie Cole, Heather Hastings, Chattavee Numtee, and Elizabeth Youman for
their assistance with various aspects of the project, as well as three anonymous re-
viewers for comments on an earlier version.
Human Nature, Vol. 12, No. 4, 2001
318
David C. Geary is the Frederick A. Middlebush Professor of Psychological Sciences
at the University of Missouri at Columbia. He has published nearly 100 articles and
chapters across a wide range of topics, including cognitive and developmental psy-
chology, education, evolutionary biology, and medicine. His two books, Children's
Mathematical Development (1984) and Male, Female: The Evolution of Human Sex Dif-
ferences (1988), have been published by the American Psychological Association.
M. Catherine DeSoto recently completed her Ph.D. in psychological sciences at the
University of Missouri at Columbia and is currently assistant professor of psy-
chobiology at the University of Northern Iowa. Her research primarily focuses on the
interface between biology and behavior, including the relation between sex
hormones and personality disorders.
Mary K. Hoard is completing her Ph.D. studies in psychological sciences at the
University of Missouri at Columbia and is currently a research specialist in the De-
partment of Psychological Sciences. Her research interests focus on children's cog-
nitive development, as well as the relation between sleep and cognitive and
psychological functioning.
Melanie Skaggs Sheldon is a graduate student in the Department of Psychological
Sciences at the University of Missouri at Columbia. Her research interests include
social cooperation, sexual behavior, and personality, as understood from an evolu-
tionary perspective.
M. Lynne Cooper is a professor of psychological sciences and director of the train-
ing program in social psychology at the University of Missouri at Columbia. She is
an associate editor of the Journal of Personality and the author of more than 60 arti-
cles and chapters in the areas of personality and social psychology. Her primary re-
search efforts involve directing a longitudinal study of risky sexual behavior of
adolescents and young adults.
NOTES
1. Two estradiol. values were more than 2 standard deviations higher than the
next highest value for the same session or week. These values were replaced with
the next highest value for the session or week.
2. Of the 32 potential correlations between sexual experience (i.e., comparing
subjects who had sexual intercourse with virgins) and responses to the imagined
emotional and sexual infidelity items, only one was significant: virgins reported
more intense anger to emotional infidelity during cycle week two than did other
females [r(44) = .29, p < .05]. The range of correlations was - .15 to .29, with the me-
dian being .09 [r(43) = .09, p > .25]. On the basis of these null findings, all subjects,
regardless of sexual experience, were used in all subsequent analyses.
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... Furthermore, jealousy seems to be affected by the use of combined oral contraceptives. Especially using formulations with higher doses of ethinyl estradiol are associated with significantly higher jealousy scores [13][14][15]. These findings indicate that estrogen plays a role in jealousy within a romantic relationship, but the exact underlying mechanism is unknown. ...
... shorter than 21 days, longer than 35 days or irregular). The use of hormonal contraceptives has been shown to increase jealousy levels and was an important covariate to include in our analyses [13,14]. ...
... Participants in our study were older and had a longer relationship duration compared to participants in other studies, who were [13,20]. The higher jealousy levels in women using combined oral contraceptives might be caused by an effect of estrogen, which is suggested to influence jealous behavior [14,15]. Progesterone dose in combined oral contraceptives is shown to be unrelated to reported jealousy, but combined oral contraceptives with higher doses of ethinyl estradiol are associated with higher jealousy compared with formulations with lower ethinyl estradiol doses [14,15]. ...
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Background: Estrogen influences susceptibility to migraine attacks and it has been suggested to affect jealousy in romantic relationships in women. Therefore, we hypothesized that migraine women may be more jealous. Methods: Jealousy levels and hormonal status were determined based on a cross-sectional, web-based, questionnaire study among female migraine patients and controls. A random sample of participants was selected from a validated migraine database. Participants with a serious and intimate monogamous relationship were included (n = 498) and divided into the following subgroups: menstrual migraine (n = 167), non-menstrual migraine (n = 103), postmenopausal migraine (n = 117), and premenopausal (n = 57) and postmenopausal (n = 54) controls. The primary outcome was the difference in mean jealousy levels between patients with menstrual migraine, non-menstrual migraine and premenopausal controls. Results were analyzed with a generalized linear model adjusting for age, relationship duration and hormonal status (including oral contraceptive use). Additionally, the difference in jealousy levels between postmenopausal migraine patients and controls was assessed. Previous research was replicated by evaluating the effect of combined oral contraceptives on jealousy. Results: Jealousy levels were higher in menstrual migraine patients compared to controls (mean difference ± SE: 3.87 ± 1.09, p = 0.001), and non-menstrual migraine patients compared to controls (4.98 ± 1.18, p < 0.001). No difference in jealousy was found between postmenopausal migraine patients and controls (- 0.32 ± 1.24, p = 0.798). Women using combined oral contraceptives were more jealous compared to non-users with a regular menstrual cycle (2.32 ± 1.03, p = 0.025). Conclusion: Young women with migraine are more jealous within a romantic partnership.
... Indeed, one of the studies that reported higher jealousy among HC users compared to NC nonusers (Geary et al., 2001) also reported that HC users were more likely to report a sexual relationship within the prior week and, that the sexual encounter was with a serious partner as opposed to a mere acquaintance or having "just met". Another consideration for this area of research is the overreliance on self-report measures of jealousy and mate guarding, attitudes and behaviors that are generally considered negative and thus, subject to social desirability. ...
... When relationship commitment was controlled for in the HC vs NC analysis, only differences in hurt remained significant. In their conclusions, Geary et al. (2001) report that patterns of jealousy varied significantly between HC users and NC women, however we caution that in this sample the effect of HCs may be conflated with relationship commitment because women in the HC group were significantly more likely to report that their most recent sexual relationship was in a committed relationship. ...
... For example, inBatres et al. (2018) the majority of HC users were in a monogamous relationship (85%) while the majority of NC women were single (81%). Similar differences were reported inGeary et al. (2001) andSchwarz and Hassebrauck (2008).These differences are important because previous research has demonstrated a mediating effect of relationship status on mating relevant behaviours across the menstrual cycle (e.g.,Haselton & Gangestad, 2006;Pillsworth et al., 2006). Relationship status also influenced the results covered in this review. ...
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Emerging evidence suggests that hormonal contraceptives (HCs) impact psychological outcomes through alterations in neurophysiology. In this review, we first introduce a theoretical framework for HCs as disruptors of steroid hormone modulation of socially competitive attitudes and behaviors. Then, we comprehensively examine prior research comparing HC users and non-users in outcomes related to competition for reproductive, social, and financial resources. Synthesis of 46 studies (n = 16,290) led to several key conclusions: HC users do not show the same menstrual cycle-related fluctuations in self-perceived attractiveness and some intrasexual competition seen in naturally cycling women and, further, may show relatively reduced status- or achievement-oriented competitive motivation. However, there a lack of consistent or compelling evidence that HC users and non-users differ in competitive behavior or attitudes for mates or financial resources. These conclusions are tentative given the notable methodological limitations of the studies reviewed. Implications and recommendations for future research are discussed.
... Various psychosocial behaviors, such as jealousy, may be influenced by hormonal contraception and correlate with estrogen levels as well (Geary et al., 2001). Jealousy drives mate retention behaviors in both the male and female which can lead to intimate partner violence (Welling et al., 2012). ...
... Women on hormonal contraceptives also used mate retention tactics more frequently. Most likely, this behavior resulted from the more intense and greater sexual jealousy that women on hormonal contraceptives feel as indicated by self-report measures (Geary et al., 2001). ...
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In the past decade, two large prospective cohort studies of British and American women have been conducted which found a statistically significant increase in the risk of violent death in ever-users of hormonal contraceptives. Research on the effects of hormonal contraceptives upon the behaviors of intimate partners and on the physiology of women using hormonal contraceptives has provided insight into the possible basis for the resulting increase in violent death. This review examines the changes that are potential contributors to the reported increase.
... Findings for shifting jealousy across the ovulatory cycle are even more mixed (Table 2). Three studies reported higher levels of jealousy when women were fertile or when estradiol levels were higher (Buunk & van Brummen-Girigori, 2016;Cobey et al., 2012;Geary et al., 2001). However, other studies did not find any compelling evidence that women's experienced jealousy changes across the cycle or tracks changes in women's estradiol and progesterone levels (Hahn et al., 2016(Hahn et al., , 2020. ...
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Research on social status competition among women suggests that underlying hormonal shifts associated with the ovulatory cycle systematically drive alterations in preferences and behavior. Specifically, it is proposed that the fertile window, marked by heightened estradiol and lower progesterone levels, is related to increased psychological motivation for intrasexual social comparison, leading to increasing competitiveness and jealousy. In this pre-registered, longitudinal study, 257 women provided saliva samples for hormone assays, rated the attractiveness of other women, and self-reported intrasexual competitiveness and jealousy across four testing sessions. Multilevel analyses revealed no compelling evidence for (hormone-related) cycle shifts in intrasexual competitiveness, attractiveness ratings, or jealousy. Rather, women higher in intrasexual competitiveness seem to rate other women as more attractive in general. We discuss how our results contribute to a growing body of literature suggesting that women’s social attitudes and preferences are more stable and less hormonally influenced than previously assumed.
... A total of 143 participants (55.4) were currently on some form of birth control medication while 113 (43.8%) were not. Birth control usage was included since prior research shows that hormonal birth control usage affects women's behavior (Welling et al., 2012) and reactions to others (see Geary et al., 2001;Wade & Fowler, 2006). ...
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We analyzed the responses of 448 participants who completed questions on attractiveness and other evolutionary fitness related traits, and long- and short-term mating potential, of a woman in either high heeled or flat shoes. We hypothesized that the woman in high heels would be rated as more attractive and evolutionarily fit by both men and women, and preferred for short-term mating by men. The hypothesis was partially supported. The woman in high heels was perceived as being more sexually attractive, physically attractive, feminine, and of a higher status. Additionally, women rated women as having a higher status regardless of the shoe, than men, while men rated women as having higher short- and long-term mating potential, than women did, regardless of the shoe. We discuss the implications of these findings.
... This is supported by a large amount of previous research on hormonal contraceptives producing mixed results for a wide range of psychological outcomes, including sexual functioning (Laessøe et al., 2014;Oranratanaphan & Taneepanichskul, 2006;Panzer et al., 2006; C. W. Wallwiener et al., 2015;M. Wallwiener et al., 2010;Zethraeus et al., 2016), libido (Caruso et al., 2005;Graham et al., 1995;Graham & Sherwin, 1993;Mark et al., 2016;McCoy & Matyas, 1996;Oranratanaphan & Taneepanichskul, 2006;Sabatini & Cagiano, 2006;Walker & Bancroft, 1990; Zethraeus et al., 2016; for reviews see Burrows et al., 2012;Davis & Castaño, 2004; Lee et al., 2017;Pastor et al., 2013;Schaffir, 2006), sexual and masturbation frequency (Alexander et al., 1990;Bancroft et al., 1991;Caruso et al., 2005;McCoy & Matyas, 1996), and sexual satisfaction (Alexander et al., 1990;Caruso et al., 2005;Jern et al., 2018;Oranratanaphan & Taneepanichskul, 2006), as well as relationship satisfaction (Jern et al., 2018;Taggart et al., 2018), jealousy (Cobey et al., 2011(Cobey et al., , 2012Geary et al., 2001;Jern et al., 2018;Welling et al., 2012) and general well-being (Caruso et al., 2005;Egarter et al., 1999;Taggart et al., 2018;Zethraeus et al., 2017). There is therefore a need for methodologically sound and rigorous studies investigating effects of hormonal contraceptives on sexuality and satisfaction. ...
Article
Many of the women who take hormonal contraceptives discontinue because of unwanted side effects, including negative psychological effects. Yet scientific evidence of psychological effects is mixed, partly because causal claims are often based on correlational data. In correlational studies, possible causal effects can be difficult to separate from selection effects, attrition effects, and reverse causality. Contraceptive use and, according to the congruency hypothesis, congruent contraceptive use (whether a woman’s current use/non-use of a hormonal contraceptive is congruent with her use/non-use at the time of meeting her partner) have both been thought to influence relationship quality and sexual functioning. In order to address potential issues of observed and unobserved selection effects in correlational data, we studied a sample of up to 1,179 women to investigate potential effects of contraceptive use and congruent contraceptive use on several measures of relationship quality and sexual functioning: perceived partner attractiveness, relationship satisfaction, sexual satisfaction, and diary measurements including libido, frequency of vaginal intercourse, and frequency of masturbation. No evidence for substantial effects was found except for a positive effect of hormonal contraceptives on frequency of vaginal intercourse and a negative effect of hormonal contraceptives on frequency of masturbation. These effects were robust to the inclusion of observed confounders, and their sensitivity to unobserved confounders was estimated. No support for the congruency hypothesis was found. Our correlational study was able to disentangle, to some extent, causal effects of hormonal contraceptives from selection effects by estimating the sensitivity of reported effects. To reconcile experimental and observational evidence on hormonal contraceptives, future research should scrutinize the role of unobserved selection effects, attrition effects, and reverse causality.
... Furthermore, the current study did not measure hormonal birth control usage among women. Prior research shows that women who were using hormonal birth control responded differently to questions regarding jealousy and infidelity than women who were not using hormonal birth control (Cobey et al. 2011;Geary et al. 2001;Wade and Fowler 2006;Welling et al. 2012). Similarly, women's ovulatory status can affect women's jealousy responses (Cobey et al. 2012), but it was not measured in the present research. ...
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Objectives Infidelity, actual or suspected, can trigger strong emotional reactions, such as jealousy, which could lead to the dissolution of the relationship. These reactions were predicted to vary with the severity of the infidelity, with the sex of the participant, with previous experience with unfaithful partners, and with the length of the relationship. Method We employed a sample of 447 Greek-speaking participants who were asked to indicate their reactions in different scenarios of infidelity. Results We found that more severe acts of infidelity were associated with higher emotional upset and jealousy and lower probability of forgiveness. Moreover, women indicated stronger emotional upset and jealousy than men, but they were more likely to forgive their partners. Furthermore, participants indicated more emotional upset and jealousy if they were in a long-term than in an early-stage relationship. Finally, participants who were older and who had experienced infidelity from their previous partners were more likely to forgive their partners’ infidelity than participants who were younger and who did not have such experience. Conclusions Our results indicated that several factors determined the severityof the reactions to infidelity.
... Both women using HCs and their male partners reported more frequent mate retention behaviors as compared to HC non-users and their male partners in a cross-sectional study by Welling et al. 127 This is in agreement with the preference for less masculine but more reliable and responsible partners ("nongenetic" benefits), more intense affective responses to partner infidelity, and greater overall sexual jealousy in HC users. 128 More recently, in a study involving 275 females who had been using COCs for at least 3 months, the authors found that using HCs with higher levels of synthetic estradiol, but not progestin, is associated with significantly higher levels of self-reported jealousy. 129 In a study by Cobey et al, 130 women reported higher levels of jealousy when their current HC use was incongruent with that at the start of the relationship as compared with women reporting HC use congruency. ...
Article
Introduction: Hormonal contraception is available worldwide in many different forms. Fear of side effects and health concerns are among the main reasons for not using contraceptives or discontinuing their use. Although the safety and efficacy of contraceptives have been extensively examined, little is known about their impact on female sexual function, and the evidence on the topic is controversial. Aim: To review the available evidence about the effects of hormonal contraceptives on female sexuality in order to provide a position statement and clinical practice recommendations on behalf of the European Society of Sexual Medicine. Methods: A comprehensive review of the literature was performed. Main outcome measure: Several aspects of female sexuality have been investigated, including desire, orgasmic function, lubrication and vulvovaginal symptoms, pelvic floor and urological symptoms, partner preference, and relationship and sexual satisfaction. For each topic, data were analyzed according to the different types of hormonal contraceptives (combined estrogen-progestin methods, progestin-only methods, and oral or non-oral options). Results: Recommendations according to the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence criteria and specific statements on this topic, summarizing the European Society of Sexual Medicine position, were developed. Clinical implications: There is not enough evidence to draw a clear algorithm for the management of hormonal contraception-induced sexual dysfunction, and further studies are warranted before conclusions can be drawn. A careful baseline psychological, sexual, and relational assessment is necessary for the health care provider to evaluate eventual effects of hormonal contraceptives at follow-up. Strengths & limitations: All studies have been evaluated by a panel of experts who have provided recommendations for clinical practice. Conclusion: The effects of hormonal contraceptives on sexual function have not been well studied and remain controversial. Available evidence indicates that a minority of women experience a change in sexual functioning with regard to general sexual response, desire, lubrication, orgasm, and relationship satisfaction. The pathophysiological mechanisms leading to reported sexual difficulties such as reduced desire and vulvovaginal atrophy remain unclear. Insufficient evidence is available on the correlation between hormonal contraceptives and pelvic floor function and urological symptoms. Both S, Lew-Starowicz M, Luria M, et al. Hormonal Contraception and Female Sexuality: Position Statements from the European Society of Sexual Medicine (ESSM). J Sex Med 2019;16:1681-1695.
... Specifically, they note that because men do not have parental certainty, sexual infidelity has the potential to be more costly for men than women. A man who is deceived may dedicate a considerable amount of his assets to rearing a genetically unrelated child, while a deceived woman will not face this problem (Geary et al., 2001). Alternatively, the pattern may reverse with emotional infidelity. ...
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This study examined the influence of the type of partner infidelity (sexual vs. emotional) and sex of participant on actual mate abandonment and mate retention behaviors. It was predicted that men would engage in significantly more mate abandonment behaviors after experiencing a physical infidelity and that women would engage in significantly more mate abandonment behaviors after experiencing an emotional infidelity. To test this hypothesis, men and women who had either experienced a sexual or emotional infidelity were recruited and were asked to complete several measures designed to indicate their behavioral responses to the infidelity. The men and women in the study showed the predicted asymmetrical pattern of behavioral choices in response to sexual and emotional infidelity.
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Objective Extra-pair mating has potentially severe costs, which favor the evolution of mechanisms that would enable people to reduce them by detecting their partners’ infidelity. Such a mechanism is romantic jealousy, and the current research attempted to examine the interplay between romantic jealousy, personality and the probability of detecting infidelity. Method We employed quantitative research methods on a sample of 916 Greek-speaking participants. Results we found that higher scorers in romantic jealousy were more likely to detect infidelity than lower scorers. The effect was independent of one’s own infidelity, sex and age. We also found that neuroticism and openness predicted the probability to detect infidelity indirectly through jealousy. More specifically, high scorers in neuroticism experienced stronger jealousy, which in turn, was associated with increased probability to detect infidelity. On the other hand, high scorers in openness experienced lower jealousy that was associated with a decreased probability of detecting infidelity. Conclusions Our results were consistent with the hypothesis that the jealousy mechanism has evolved to enable individuals to detect infidelity.
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In species with internal female fertilization, males risk both lowered paternity probability and investment in rival gametes if their mates have sexual contact with other males. Females of such species do not risk lowered maternity probability through partner infidelity, but they do risk the diversion of their mates' commitment and resources to rival females. Three studies tested the hypothesis that sex differences in jealousy emerged in humans as solutions to the respective adaptive problems faced by each sex. In Study 1, men and women selected which event would upset them more—a partner's sexual infidelity or emotional infidelity. Study 2 recorded physiological responses (heart rate, electrodermal response, corrugator supercilii contraction) while subjects imagined separately the two types of partner infidelity. Study 3 tested the effect of being in a committed sexual relationship on the activation of jealousy. All studies showed large sex differences, confirming hypothesized sex linkages in jealousy activation.
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When asked to choose which would be most upsetting, a mate’s sexual or emotional infidelity, past research has demonstrated that men are more likely than women to choose sexual infidelity, whereas women are more likely than men to choose emotional infidelity. Explanation of this sex difference has been controversial. In the current study we attempted to replicate previous research by examining a sample of college students in Sweden. In doing so, we also investigated the “double-shot” explanation. In the current study, the majority of men chose the sexual infidelity scenario as most upsetting, whereas the majority of women chose the emotional infidelity scenario as most upsetting. Contrary to the double-shot explanation, choice of scenario was unrelated to attitudes regarding whether the other sex was capable of satisfying sexual relations outside of a love relationship.
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In the current resurgence of interest in the biological basis of animal behavior and social organization, the ideas and questions pursued by Charles Darwin remain fresh and insightful. This is especially true of The Descent of Man and Selection in Relation to Sex, Darwin's second most important work. This edition is a facsimile reprint of the first printing of the first edition (1871), not previously available in paperback. The work is divided into two parts. Part One marshals behavioral and morphological evidence to argue that humans evolved from other animals. Darwin shoes that human mental and emotional capacities, far from making human beings unique, are evidence of an animal origin and evolutionary development. Part Two is an extended discussion of the differences between the sexes of many species and how they arose as a result of selection. Here Darwin lays the foundation for much contemporary research by arguing that many characteristics of animals have evolved not in response to the selective pressures exerted by their physical and biological environment, but rather to confer an advantage in sexual competition. These two themes are drawn together in two final chapters on the role of sexual selection in humans. In their Introduction, Professors Bonner and May discuss the place of The Descent in its own time and relation to current work in biology and other disciplines.
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As predicted by models derived from evohttionary psychology. men within the United States have been shown to exhibit greater psychological and physiological distress to sex- ual than to emotional infidelity of their partner, and wotnen have been shown to exhibit more distress lo emotional than to sexual infidelity. Because cross-cultural tests are critical for evolutionary hypotheses, we examined these sex differences in three parallel studies conducted in the Netherlands fN = 207j, Germany fN = 200), and the United States fN = 224). Two key findings emerged. First, the sex differences in sexual jealousy are robust across these cultures, providing support for the ev- olutionary psychological model. Second, the magnitude of the sex differences varies somewhat across cultures—large for the United States, medium for Germany and the Netherlands. Dis- cussion focuses an the evolutionary psychology of jealousy and on the sensitivity of sex differences in the sexual sphere to cultural input. tionship (Daly & Wilson, 1988). Given an emotion powerful enough to provoke violent and sometimes lethal reactions, sex- ual jealousy can hardly be considered to be a peripheral emo- tion from the perspectives of the magnitude of arousal, the co- herence of events that trigger its activation, and the magnitude of impact on people's lives. Indeed, from these perspectives, a compelling case can be made for the primacy of sexual jealousy as a basic human emotion and for the urgency of understanding its nature and functioning.