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Evolutionary Behavioral Sciences
Quantitative Sex Differences in Response to the
Dissolution of a Romantic Relationship
Craig Eric Morris, Chris Reiber, and Emily Roman
Online First Publication, July 13, 2015. http://dx.doi.org/10.1037/ebs0000054
CITATION
Morris, C. E., Reiber, C., & Roman, E. (2015, July 13). Quantitative Sex Differences in
Response to the Dissolution of a Romantic Relationship. Evolutionary Behavioral Sciences.
Advance online publication. http://dx.doi.org/10.1037/ebs0000054
Quantitative Sex Differences in Response to the Dissolution of a
Romantic Relationship
Craig Eric Morris and Chris Reiber
Binghamton University (SUNY)
Emily Roman
University College London
We gathered data that would allow us to examine evolutionarily informed predictions
regarding emotional and physical responses to a breakup—a cluster of correlated
responses we refer to as postrelationship grief (PRG). We tested predictions of the
existing biological model of human mating and looked to replicate or expand on the
extant literature by surveying 5,705 participants in 96 countries (M
age
⬇27 years).
Seventy-five percent of respondents experienced a breakup and 75% of those individ-
uals experienced multiple breakups. Most responses differed significantly by sex.
Emotional response was more severe than physical, with women expressing higher
levels than men in each instance. Distribution of responses was similar between sexes.
Intensity of emotional response for both sexes was notable: median (and mean)
response of nearly 7 (of 10). Component responses, both physical and emotional, again
showed significant variation but similar distributions. Women initiated breakups more
frequently. Rejected individuals experienced higher PRG levels than those initiating the
breakup or breakups via mutual agreement; however, the PRG experience was still
relatively severe for both parties. “Lack of communication,” was the most prevalent
breakup cause. This initial investigation suggests that PRG requires continued study.
Keywords: relationship termination, sex differences, breakups, sexual strategies theory,
postrelationship grief
Romantic relationships appear to be a univer-
sal human experience (Fisher, 1995; Jankowiak,
1995). Most individuals will enter and exit a
series of romantic relationships throughout their
lifetimes based on their varying needs for ro-
mance, physical and emotional support, and
sexual exclusivity (Fisher, 2006a, 2006b;
Jankowiak, 2008). For the majority of individ-
uals, this process is cyclical; most relationships
are not “for life”—individuals will experience
failed relationships before (possibly) forming a
lifelong pair bond (Buss, 2003; Fisher, 2005).
Extant research has shown that upward of 85%
of individuals will experience at least one ro-
mantic relationship dissolution in their lifetime
(Battaglia, et al., 1998; Morris & Reiber, 2011).
The formation and maintenance of romantic
relationships is well represented in evolutionary
research. From Trivers’s (1972) parental invest-
ment model to Symons’s (1979) biological
model of human mating, through Buss’s (2003)
sexual strategies model of human sexual inter-
actions, the proximate mechanisms and behav-
iors (e.g., physical attraction, mate guarding,
sex) and ultimate causation (i.e., reproductive
success) of human romantic attachments have
been major topics of study for human behav-
ioral ecologists and evolutionary psychologists.
However, from an evolutionary perspective, the
termination of romantic relationships is less
well-studied.
Loss of a partner generally provokes concom-
itant emotional reactions. In The Nature of
Grief, Archer (1999) explored grief induced by
Craig Eric Morris and Chris Reiber, Department of An-
thropology, Binghamton University (SUNY); and Emily
Roman, Department of Psychology, University College
London.
We thank Binghamton University’s Evolutionary Studies
Program (EvoS), which provided two grants in support of
the project. We thank Sheena Finlayson of Binghamton
University for her enthusiastic assistance with this ongoing
research program.
Correspondence concerning this article should be ad-
dressed to Craig Eric Morris, Department of Anthropology,
Binghamton University (SUNY), P.O. Box 6000, Bingham-
ton, NY 13902. E-mail: craig.eric.morris@gmail.com
This document is copyrighted by the American Psychological Association or one of its allied publishers.
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Evolutionary Behavioral Sciences © 2015 American Psychological Association
2015, Vol. 9, No. 3, 000 2330-2925/15/$12.00 http://dx.doi.org/10.1037/ebs0000054
1
widowhood, arguing that such grief is a result of
a “trade-off” between costs and benefits. Hu-
mans establish romantic bonds that have multi-
ple advantages and great adaptive value but
there is a cost—a series of emotions and behav-
ioral responses—if a partner dies. Archer called
this “the cost of commitment” (p. 62). Impor-
tantly, these responses are often magnified by
concurrent (possibly preexisting) mental and
physical traits of the individuals involved in the
breakup (e.g., anxiety, addictions, depression;
Barbara & Dion, 2000; Fisher, 2004; Mearns,
1991). Grief often leads to depression that is
often accompanied by, and inextricable from,
related states (e.g., sadness, demoralization,
guilt, boredom) (Keller & Nesse, 2005). Nesse
suggested that the failure of “major social en-
terprises” (e.g., romantic relationship, friend-
ships, careers) often leads to grief and serious
depression. Although the term breakup is a col-
loquialism, it will be used here as a way of
differentiating relationships dissolved by the
choice of one or more of the partners (the focus
of this study) from those terminated by the
death of a partner.
Breakups trigger an interrelated series of
emotions and behaviors (Bakermans-Kranen-
burg & van IJzendoora, 1997; Barbara & Dion,
2000; Fisher, 2006a; Morris & Reiber, 2011).
Boelen and Reijntjes (2009) found that those
who had preexisting issues with depression and
anxiety expressed stronger emotional problems
following a breakup. A longitudinal study on
forecasting error found that those who were
more in love with their partners, who thought it
was unlikely that they would soon enter a new
relationship, and who did not initiate the
breakup, made especially inaccurate predictions
about their responses to the breakup (Eastwick
et al., 2008). Fisher (2004) has argued that “We
humans are soft-wired to suffer terribly when
we are rejected by someone we adore” (p. 1).
After studying individuals who had recently
suffered a breakup, Fisher concluded that: (a)
being rejected in love is among the most painful
experiences a human being can endure; (b) de-
serted lovers often become obsessed with win-
ning back their former mate; (c) separation anx-
iety is expected; and (d) “abandonment rage” is
likely, particularly in men. We argue that, in
many relationships, Archer’s “cost of commit-
ment” must also be paid after a breakup, initi-
ating a complex suite of emotional states (e.g.,
depression, sadness, anxiety, rage), physical re-
sponses (e.g., insomnia, eating disorders, panic
attacks), and behaviors that we refer to as
postrelationship grief (PRG; Morris & Reiber,
2011).
Evolutionary approaches to romantic and
sexual relationships in humans are well repre-
sented in the psychological and biocultural lit-
erature. Drawing from the parental fitness
model of Trivers (1972), Symons (1979) pro-
posed a model of human pair bonds based on
gamete size and mobility, in which women are
predicted to invest more physical and emotional
resources in a romantic relationship than men,
due to the requisite evolved biological costs of
a possible pregnancy. Men, if they choose, can
exit a mating encounter with no risk of addi-
tional biological cost. The relatively low cost to
men leads to predictions of higher male promis-
cuity (Symons, 1979). This is the “investment
model” of human pair bonding. Buss (2003)
extended this line of reasoning to include the
“men compete/women chose” model of pair
bonding. This model proposed that men must
acquire and situate their resources in such a way
that they can win intrasexual competitions and
secure mating partners who are carefully eval-
uating men based on their resource acquisition,
display, and deployment (Buss, 2003). Addi-
tionally, Clutton-Brock and Vincent (1991)
demonstrated the sex that has a faster potential
reproductive rate (in this case, men) will face
higher intrasexual competition for mates while
the sex with a slower reproductive rate (women)
will be more selective when choosing potential
mates.
In short, (a) men must compete among them-
selves for mate access to a higher degree than
women and are more prone to want multiple
mates (Schmitt, Shackelford, & Buss, 2001);
and (b) women, in general, are expected to be
more selective in choosing a mate, particularly
when employing a long-term mating strategy
because they are likely to need various forms of
assistance (e.g., time, energy, resources) to re-
produce successfully (Buss & Shackelford,
2008). However, conflicting predictions con-
cerning males’ responses to breakups can be
derived from these premises. If males are se-
lected to be highly competitive and promiscu-
ous, the termination of a relationship should not
be particularly traumatic to males, because they
will quickly move to another female. However,
2 MORRIS, REIBER, AND ROMAN
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if females are particularly choosy concerning
partners, the termination of a relationship
should be highly traumatic for males, because
they may expect to have a difficult time accru-
ing a new mate. In addition, it is likely that
those employing a short-term mating strategy
(both women and men) may experience break-
ups differently than those employing a long-
term strategy. However, we know of no current
metric that allows for inclusion of this variable,
because it has been argued that individuals are
likely not consciously aware of the particular
mating “strategy” they are employing at any
given time (Buss, 2003).
Breakups happen to the majority of individ-
uals at some point in their life, usually more
than once, and have the potential to be one of
the most traumatic experiences individuals may
ever face in their lives (Chung et al., 2003;
Fisher, 2004). As part of sexual strategies the-
ory, Buss enumerated the causes for failure of
romantic relationships for ancestral humans.
These include: partner imposing unacceptable
costs, lost resource availability due to illness or
injury, infertility, infidelity, lost mating oppor-
tunities, compelling mating alternatives becom-
ing available, inadequate care for children, psy-
chological abuse, physical abuse, and death of a
partner (Buss, 2003; Schmitt & Shackelford,
2003). More recently, Wade (2012) demon-
strated that sexual conflict—which may include,
but is not limited to infidelity (e.g., unmet sex-
ual expectations, insufficient communication re-
garding sexual behaviors)—is a cause for rela-
tionship dissolution; in this particular instance,
it the man who is more likely to initiate the
breakup with the woman. In a pilot study of
1,735 university students, Morris and Reiber
(2011) found that for individuals who had ex-
perienced a breakup: the termination of a ro-
mantic relationship elicited dramatic physical
and emotional responses in over 95% of respon-
dents and both men and women experienced
PRG with virtually identical frequency and in-
tensity, but expressed PRG very differently.
One study that explored the cause of and
responses to breakups using an explicit evolu-
tionary model found that women had more neg-
ative feelings following a breakup than men
(Perilloux & Buss, 2008). This finding con-
trasted with previous studies that suggested it is
men who experience breakups with stronger
negative emotions than women (Choo et al.,
1996; Sprecher, 1994; Sprecher et al., 1998).
Perilloux and Buss (2008) also found that
women tend to report more personal growth
after breakup, which mirrors the findings of
other research (Bevvino & Sharkin, 2003;
Mearns, 1991; Tashiro & Frazier, 2003). A ma-
jor finding of Perilloux and Buss was that those
who initiated the breakup had significantly dif-
ferent emotional responses than those who were
rejected.
In contrast to most previous work in this area,
which been based on small college samples, the
current study undertook to investigate breakups
in a large-scale population-based sample in-
cluding variables related to more representative
ranges of cultural, temporal, and sexual ecolo-
gies. We set out to investigate whether results
from earlier work would be replicated in a large
sample and whether existing and expanded pre-
dictions about breakup response are supported.
We predicted that men and women would vary
in their expression of PRG behavior, but that the
intensity of the experience would be more sim-
ilar than we would expect by using the men
compete/women chose model. We predicted
that the party who was rejected in the relation-
ship would suffer higher overall PRG but we
also predicted that, in most instances, both par-
ties would suffer relatively high PRG levels.
We sought to explore the causes of relationship
dissolution and to evaluate whether the pre-
dicted evolutionary causes (e.g., male infidelity,
infertility) would be represented in a large,
cross-cultural population. Lastly, we sought to
explore the intensity and expression of PRG in
a large population to evaluate whether the ex-
periences reported by this population would dif-
fer from or replicate prior findings (Perilloux &
Buss, 2008; Morris & Reiber, 2011).
Method
Two studies were conducted online between
June 2012 and March 2013. The invitations and
survey questions were only offered in English.
A secure link led to the survey instructions.
Participants were told this was an academic
survey about past romantic relationship experi-
ences, that responses were confidential, and that
they: were not obligated to answer all questions,
could quit the survey at any time, and could take
as much time as needed (although each survey
was designed to be completed in approximately
3SEX DIFFERENCES IN BREAKUP RESPONSE
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15 min). Respondents could not access either
survey until agreeing to participate in the study,
and were given contact information for the prin-
cipal investigator if they had questions or con-
cerns related to the study. No tangible material
or monetary compensation was offered to par-
ticipants. This method of acquiring an informed
consent follows the recommendations of the
Board of Scientific Affairs’ Advisory Group on
the Conduct of Research on the Internet (Kraut
et al., 2004). The surveys were hosted by Qual-
trics, which has SAS 70 Certification and meets
the privacy standards of the Health Insurance
Portability and Accountability Act. Qualtrics
provides a filter option that permits only one
survey submission from any individual IP ad-
dress to prevent “ballot stuffing.” This filter
option was in effect for both surveys (i.e., no
individual could take both surveys from the
same IP address). All responses were labeled
with random 15-digit alphanumeric codes, and
no other identifying information was associated
with any responses. No names or email ad-
dresses were collected during recruitment or
data analyses. These studies were approved by
Binghamton University’s Human Subjects Re-
search Review Committee, and all research was
performed by certified investigators who con-
formed to the guidelines for the ethical treat-
ment of human subjects.
Approximately 295,000 individuals were in-
vited and 5,705 participated, a response rate of
1.8%. Study B invitations were sent to different
individuals than Study A, but an attempt was
made to keep the approximate proportions of
invitations comparable (i.e., total numbers of
Facebook invitations, academic listervs, and on-
line forums were comparable). The total num-
ber of invitees (about 295,000) reflects only
recorded contacts—the true reach of the survey
is unknowable (e.g., a department chair may
have taken the survey, distributed it to her de-
partment, distributed it university-wide, or all/
some/none of these actions).
Survey contacts were invited to participate in
a brief survey on romantic relationships. No
mention of breakups, divorce, or relationship
termination was made in the invitation. Partic-
ipants provided demographic information and
responses to questions about romantic relation-
ship history and, if applicable, breakups (e.g.,
Have you experienced a breakup? How severe
was the breakup for you emotionally? Who do
you feel initiated the breakup? What sort of
physical responses did you experience as a re-
sult of the breakup?). If respondents had expe-
rienced multiple breakups, they were asked to
identify and confine responses to one breakup of
their choosing (e.g., the most recent, the one
that affected them most). Respondents were
asked to report a self-assessment of their mate
value— using whatever criteria they felt was
applicable—and to rate their emotional re-
sponse and physical response to their selected
breakup on a scale from 0 (none)to10(unbear-
able). Participants were also asked to identify
the components of their emotional and physical
responses; they were provided a list of common
responses that was generated from earlier pilot
research, and were asked to endorse as many as
applied to them. For analysis purposes, total
response was calculated by summing (emo-
tional response ⫹physical response) to reflect
how severe a breakup experience was, overall,
on a scale from 1–20. In direct tests of a priori
predictions, we used a two-tailed alpha level of
.05 and calculated Cohen’s das a measure of
effect size.
The two surveys (A and B) differed in two
major ways. First, due to the high level of
“other” responses to multiple choice questions
(e.g., breakup cause) in Survey A, Survey B was
modified to include a text box allowing partic-
ipants to specify or elaborate on what they
meant by “other.” Because the analysis of these
textual responses is beyond the scope of this
article, quantitative data from the two studies
were combined when possible for the analyses
shown here. In addition, initial analysis demon-
strated that depression was often accompanied
by sadness, yet sadness itself was so frequently
mentioned in the optional commentaries in Sur-
vey A that it was added as an additional cate-
gory of emotional response in Survey B.
Table 1
Demographic Information for Participants Who
Experienced a Breakup
Demographic variables Men Women
N1,490 2,834
Age, years 26.8 (4.66) 26.46 (4.07)
Income, U.S.$ 26,714 (2.96) 22,589 (2.51)
Self-reported mate value
a
7.64 (2.01) 7.88 (1.93)
Note. Values are Nor M(SD).
a
Scale range: 1–10.
4 MORRIS, REIBER, AND ROMAN
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Results
Of the approximately 295,000 invited individ-
uals, 5,705 participated. These individuals repre-
sented 96 countries and all 20 of the of the U.S.
Census Bureau occupation types. Only 38% of
respondents were undergraduate or graduate stu-
dents. The five countries with the most respon-
dents were the United States (63%), India (7%),
Canada (5%), and the United Kingdom and Ger-
many (3% each); the remaining 91 countries rep-
resented only 19% of respondents. Demographic
information on survey participants can be seen in
Table 1. Both samples included individuals from
all sexual orientations self-selected from the fol-
lowing choices: exclusively heterosexual, mostly
heterosexual, bisexual, mostly homosexual, exclu-
sively homosexual, asexual, and other. The pro-
portion of self-selected sexual orientation of re-
spondents can be seen in Table 2. The PRG
experiences of this substantial population are the
topic of a forthcoming publication.
Respondents reported self-assessments of mate
value on a scale from 1–10, with 10 being highest.
Men (N⫽1,092) reported a mean mate value of
7.54 (SD ⫽1.95, Mdn ⫽8); women (N⫽1,756)
reported a mean mate value of 7.84 (SD ⫽1.81,
Mdn ⫽8). In this sample, over 90% of individuals
rated themselves as 7⫹on a 10-point Mate Value
Scale, which rendered that metric unusable in our
analyses. Across both surveys, 2,834 women
(84%) and 1,490 men (79%) reported experienc-
ing a breakup. Of these, 2,318 women (82%) and
1,159 men (78%) experienced multiple breakups.
Of those who had experienced multiple breakups,
women experienced an average of 4.10 (SD ⫽
2.58) and men, 3.86 (SD ⫽2.22). These respon-
dents were asked to address one breakup of their
choosing for the remainder of the survey queries.
The length of these selected relationships aver-
aged 2.9 years (SD ⫽2.68) for women (N⫽
2,813) and 2.51 years (SD ⫽2.47) for men (N⫽
1,482), t⫽4.576 (4,158), p⬍.001. Responses
addressing relationship length were not submitted
by .07% of women and .05% of men. For women
(N⫽2,695), the mean level of emotional response
was 6.84 (SD ⫽2.52) and for men (N⫽1,409),
6.58 (SD ⫽2.58), t(4102) ⫽3.115, p⫽.002, d⫽
.102. This difference was statistically significant,
but with a very small effect size. Physical re-
sponse levels were lower overall; the mean PR for
women (N⫽2,682) was 4.21 (SD ⫽2.94) and for
men (N⫽1,398), 3.75 (SD ⫽2.93), t(4078) ⫽
4.677, p⬍.001, d⫽.157. Again, the sex differ-
ence was statistically significant, but with a small
effect size. The distribution of physical and emo-
tional response levels by all respondents of each
sex can be seen in Figure 1. The basic components
of emotional and physical responses identified by
all male and female respondents are shown in
Figure 2. The initiator of the breakup, as reported
by all respondents of each sex, is shown in Figure
3. Figure 4 shows emotional, physical, and total
response levels.
Respondents to Survey A were asked what caused
their breakup.
1
Response options were not mutually
exclusive. The results for women (N⫽1,966) and
men (N⫽1,125) are shown in Figure 5. The emo-
tional, physical, and total response based on the
cause of breakup is shown by sex in Figure 6.
Discussion
The purpose of this study was to examine
evolutionarily informed predictions regarding
emotional and physical responses to a break-
up—a cluster of correlated responses that we
refer to as PRG. We sought to test multiple
1
Respondents to Survey B were asked to “describe what
caused your breakup” in text form only. This resulted in
1,123 responses, totaling 40,752 words. These results re-
quire qualitative analyses that are beyond the scope of this
initial inquiry.
Table 2
Distribution of Male and Female Self-Reported Sexual Orientation
Exclusively
heterosexual
Mostly
heterosexual Bisexual
Mostly
homosexual
Exclusively
homosexual Asexual
a
Other
Men 72% 11% 5% 2% 7% 1% 2%
Women 61% 21% 8% 2% 3% 3% 2%
a
From the Asexual Visibility and Education Network: “Asexuals may regard other people as aesthetically attractive without
feeling sexual attraction to them. Some asexual people also experience the desire of being romantically attracted to other
people without it being sexual” (Asexual Visibility and Education Network, n.d.).
5SEX DIFFERENCES IN BREAKUP RESPONSE
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Distribution of Response Levels to a Breakup
Emotional Response Level
12345678910
stnednopseR fo noitropo
r
P
0.00
0.05
0.10
0.15
0.20
0.25
Men
Women
Physical Response Level
12345678910
stnednopseR fo noitroporP
0.00
0.05
0.10
0.15
0.20
0.25 Men
Women
Figure 1. Distribution of emotional (A) and physical (B) response levels to a breakup, by
sex.
6 MORRIS, REIBER, AND ROMAN
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This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
predictions of the biological model stemming
from the work of Trivers (1972), Symons
(1979), and Buss (2003), and looked to replicate
or expand on the extant findings.
Nearly three quarters of respondents had ex-
perienced a breakup. Of these respondents, an
additional three quarters had experienced mul-
tiple breakups—roughly four each for both
sexes. Because the mean age of respondents of
both sexes was approximately 27 years, we con-
clude that having multiple breakups, relatively
early in life, is the norm rather than the excep-
tion. This suggests that just as mate attraction,
mate guarding, and mate retention tactics are
products of evolution, so too must be PRG
itself, as well as a means of mitigating the PRG
experience and “moving on.” As Fisher (2004)
asked: “Why did our ancestors evolve brain
links to cause us to hate the one we love?
Perhaps because it enabled jilted lovers to ex-
tricate themselves and start again” (p. 43).
In most instances, the mean responses to a
breakup differed significantly by sex, however,
virtually all effect sizes (using Cohen’s d) were
negligible to small. Emotional response to a
breakup was substantially more severe than phys-
ical response for both sexes, with women express-
ing significantly higher levels than men in each
Component Responses of Those Who Experienced A Breakup
Emotional Response
Anger Anxiety DepressionNumbness Fear Lost Focus Inabilty
stnednopseR fo noitroporP
0.0
0.2
0.4
0.6
0.8
1.0
Men
Women
Physical Response
Food Panic Immune Insomnia Weight
stnedn
o
ps
e
R f
o
noitroporP
0.0
0.2
0.4
0.6
0.8
1.0
Men
Women
Figure 2. Components of emotional (A) and physical responses (B) to a breakup, by sex.
The xaxis legend in panel A is Anger; Anxiety; Depression; Emotional numbness; Fear;
General loss of focus; and Inability to function at school or work. The xaxis legend in panel
B is Nausea and/or inability to eat; Panic attacks; Reduced immune system function;
Insomnia; and Unwanted weight loss/gain.
7SEX DIFFERENCES IN BREAKUP RESPONSE
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instance. However, the distribution of responses is
remarkably similar across the sexes—an occur-
rence not predicted by a coarse interpretation of
the biological model. Equally striking is the inten-
sity of the emotional response for both sexes.
Considering that a response level of 0 indicated
“no effect” while 10 indicated “unbearable,” the
median (and mean) response of nearly 7 for both
men and women is notable. As with intensity of
response, the component responses, both physical
and emotional, showed statistically significant
variation in most instances, but similar distribu-
tions by sex. Important, perhaps predictably, is the
higher rate of a “fear” response in women as well
as the extremely high rate of insomnia for both
men and women. Unwanted weight loss or gain
was also far more common in women than men,
but if the qualitative analyses mirror our pilot
study (Morris & Reiber, 2011), this response will,
contrary to the stereotype, involve substantial un-
wanted weight loss.
Women initiated breakups more often than
men. Women reported initiating the breakup
39% of the time versus men at 37%, with a
mutual decision at 24%. Men reported initiating
the breakup 28% of time versus women at 47%,
with a mutual decision at 25%. These findings
mirror the trend, but to a lesser degree than
those found in a 100-year survey of U.S. di-
vorce rates by Brinig and Allen (2000), who
found that women initiated the divorce in al-
most 70% of legal cases. Those who were re-
jected also suffered significantly higher levels
of overall PRG than those who initiated the
breakup or in instances where the relationship
was dissolved by mutual agreement. However,
it should be noted that, regardless of the initia-
tor, the PRG experience was still relatively se-
vere for both parties.
The biological model suggests that infidelity,
primarily male, is by far the most common
cause of breakups (Symons, 1979; Einon, 1994;
Buss & Schmitt, 1993; Drigotas & Barta, 2001;
Schmitt et al., 2001). The data from this larger
population does not support that argument.
“Lack of communication” was selected nearly
twice as often as infidelity, by roughly half of
men and women as the number one reason for
the breakup. However, these causal options
were not mutually exclusive and, furthermore,
the high rate of “other” as a breakup cause
clearly demonstrates that the complexity of this
phenomenon requires additional study.
This initial investigation into PRG suggests that
the topic is one that avails itself to continued
study. Although the survey response rates were
low (approximately 2%), the sample size is quite
large. Also, the attentiveness with which partici-
pants engaged the surveys (approximately 87% of
participants completed the full survey) and the
surfeit of qualitative data gathered from the op-
tional additional comments (over 400,000 words
of text) suggest that continued investigation along
these lines will provide meaningful information
on relationship termination.
Limitations and Future Directions
Any Internet-based survey presents its own
set of limitations. The reach of the surveys in
unknowable, and therefore a true response rate
is incalculable. However, valuable data are at-
Initiator
Self Partner Mutual
stnednopseR fo noitroporP
0.0
0.1
0.2
0.3
0.4
0.5
Men
Women
F=34.8; df=1; p<.0001
Figure 3. Initiator of breakup by sex. F(1) ⫽34.8, p⬍.001.
8 MORRIS, REIBER, AND ROMAN
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This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Emotional Response
Initiator
Self Partner Mutual
)01-1( leveL esnopseR lanoitomE
0
2
4
6
8
10
Men
Women
Total Response
Initiator
Self Partner M utual
)02-1(
l
eve
L
e
s
nopseR
latoT
0
5
10
15
20
Men
Women
Physical Response
Initiator
Self Partner Mutual
)0
1-1
(
le
veL
esno
p
s
e
R
l
a
cisyhP
0
2
4
6
8
10
Men
Women
F=1291.2; df=1; p<.0001
F=855.0; df=1; p<.0001
F=1173.3; df=1; p<.0001
Figure 4. Mean (standard deviation) emotional (A), physical (B), and total (C) response
levels by initiator of breakup and sex. Panel A: F(1) ⫽1,291.2, p⬍.001; panel B: F(1) ⫽
855.0, p⬍.001; and panel C: F(1) ⫽1,173.3, p⬍.001.
9SEX DIFFERENCES IN BREAKUP RESPONSE
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This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
tainable using the Internet if the project is ap-
proached in a logical and diligent manner (e.g., be
inclusive with the targeting of groups, striving for
representative group samples). Moreover, anony-
mous and confidential Internet-based research is
an ideal way to let subjects “speak with their own
voice” on sensitive topics (e.g., sexual behavior,
pornography use, sexually transmitted infections)
without interviewer bias and other dilemmas as-
sociated with lab interviews.
In addition, the survey was offered only in
English—a conscious choice. Although the sur-
vey host service offered thorough translation
options, we felt the subject matter and question
wording would, literally, get lost in translation.
Hence, although 89 countries are represented,
the participants were all English speakers. This
may alter the true “cross-cultural” nature of the
surveys.
As with any survey instrument, particularly
one distributed internationally, survey design
is fundamental. To ensure that our data cap-
tured the reality of participants, our method-
ology included a pilot survey, an initial sur-
vey, and a final survey that were refined at
each step to address any issues that appeared.
For example, participants spontaneously
noted “sadness” so often in the “other” cate-
gory of Survey A’s emotional responses (via
optional comments) that we included it as a
separate category in Survey B— one that was
widely selected (83% of men and 82% of
women selected this new category in Survey
B). This is a key example of letting subjects
speak for themselves.
Mate value clearly plays a major role in any
study of this type (Buss & Schmitt, 1993). How-
ever, in this sample, over 90% of individuals
rated themselves as 7⫹on a 10-point Mate
Value Scale with a median value of 8, which
rendered that metric unusable in our analyses. A
more sophisticated survey instrument would
yield more accurate information that would be
particularly valuable as related mate value dif-
ferences in PRG response.
Cause of Breakup
Infidelity
Distance
Lack of communication
Actions of others
Other
stnednopseR fo noitroporP
0.0
0.1
0.2
0.3
0.4
0.5
0.6 Men
Women
F=161.1; df=4; p<.0001
Figure 5. Distribution of cause of breakup as reported by sex. F(4) ⫽161.1, p⬍.001.
10 MORRIS, REIBER, AND ROMAN
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This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Physical Response
Cause of Breakup
Infidelity
Distance
Lack of communication
Actions of others
Other
)01-
1
( l
e
v
e
L
es
nopseR lacisyhP
0
2
4
6
8
10
Men
Women
Emotional Response
Cause of Breakup
Infidelity
Distance
Lack of communication
Actions of others
Other
)
01
-1
(
leveL
es
n
opseR lano
i
tom
E
0
2
4
6
8
10
Men
Women
F=8973.1; df=1; p<.0001
F=532.8; df=1; p<.0001
Total Response
Cause of Breakup
Infidelity
Distance
Lack of communication
Actions of others
Other
)02-1( leveL esnopseR latoT
0
5
10
15
20
Men
Women
F=13212.7; df=1; p<.0001
Figure 6. Mean (standard deviation) emotional (A), physical (B), and total (C) response
levels by cause of breakup and sex. Panel A: F(1) ⫽8,973.1, p⬍.001; panel B: F(1) ⫽532.8,
p⬍.001; and panel C: F(1) ⫽1,3212.7, p⬍.001.
11SEX DIFFERENCES IN BREAKUP RESPONSE
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Lastly, as with any study of this scope on a
complex human behavior, more questions were
raised than were answered. Other lines of in-
quiry are apparent and immediate:
1. Will the information gathered vary and/or
be correlated with complex identities
(e.g., relationship history, life history
stage, sexual identity)?
2. Does the PRG experience vary cross-
culturally and, if so, in what ways?
3. A pilot study (Morris & Reiber, 2011)
demonstrated that men and women may
“feel” a breakup in similar ways, but their
postbreakup behavior varies dramatically.
Will this finding be replicated in this
wider sample?
4. What is causing the “second peak” in
physical response levels? Is it individual-
based (e.g., a result of attachment style,
relationship history, age) or relationship-
based (e.g., dependent on the cause of the
breakup)?
5. Of particular importance as this project
moves beyond simple sex differences is
whether intrasexual variation in PRG re-
sponse may be more significant than inter-
sexual variation in both intensity and ex-
pression.
6. Lastly, in our pilot study and both iterations
of the survey reported here, women consis-
tently participated nearly three times as often
as did men. How do we gather more infor-
mation on the experiences of men, and what
will we find? Are they the epitome of the
“promiscuous male” who has so little invest-
ment in relationships that they have no re-
sponse to a breakup and thus no reason to
participate in such a study? Are they exam-
ples of the purported “loser male” who has
limited access to a romantic partner?
We suggest that men who recover quickly
from a breakup while experiencing low levels
of PRG may be those who possess sufficient
resources so that future mates will readily
choose them. Males who have low resources
and are unlikely to be selected by “choosey
women” should experience severe and long-
lasting PRG. However, by expressing a strong
negative response to a breakup, a man may be
signaling to rivals and potential future part-
ners that he expects to have a difficult time
acquiring a new mate—a behavior that is,
evolutionarily, harmful to reproductive suc-
cess. Therefore, the most adaptive behavior
for men who have experienced a recent
breakup may be to behave as if the breakup
has not affected them—men who are “win-
ners” would not care about the breakup be-
cause they would have the ability to quickly
move on to another relationship. Conversely,
or perhaps for this very reason, is it possible
that a portion of the male population suffers
PRG so severely that they are unable even to
consider participation in any such study that
addresses a past romantic failure?
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Received February 12, 2015
Revision received May 18, 2015
Accepted May 18, 2015 䡲
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