Individuals who are more socially conservative or religious tend to have lower sexual disgust thresholds; this relationship is hypothesized to be motivated to avoid contact with pathogens

Six dimensions of sexual disgust. Courtney L.Crosby et al. Personality and Individual Differences, Volume 156, April 1 2020, 109714. https://doi.org/10.1016/j.paid.2019.109714

Abstract: Sexual disgust is an emotion hypothesized to deter individuals from engaging in sexual activities that are probabilistically detrimental to fitness. Existing measures of sexual disgust are limited in treating sexual disgust as a unitary construct, potentially missing its multidimensional nature, and inadvertently ignoring important adaptive problems that this emotion evolved to solve. We conducted three studies to address these limitations. In Study 1, women and men (N = 225) nominated over 2,300 unique items that they considered sexually disgusting across a variety of different contexts. Study 2 (N = 331) identified a six-factor structure of the 50 most frequently nominated items: Taboo, Oral sex, Promiscuity, Hygiene, BDSM, and Same-sex attraction. Moreover, this study established construct validity with significant associations between sexual disgust and major dimensions of personality. Correlations between the Three Domains of Disgust Scale and our six-factor measure of sexual disgust established convergent validity. Study 3 (N = 318) confirmed the factor structure found in Study 2, established further convergent validity and examined sex differences and other individual differences in sexual disgust. Discussion focuses on the theoretical importance and psychometric validity of the Sexual Disgust Inventory–a new six-factor measure of sexual disgust.



3.1.3. Sexual disgust, religiosity, and political ideology
Individuals who are more socially conservative or religious tend to have lower disgust thresholds (Inbar, Pizarro, Iyer & Haidt, 2012; Olatunji, 2008). This relationship is hypothesized to exist as a function of the behavioral immune system, which motivates individuals to avoid contact with pathogens (Schaller & Duncan, 2016). This is a robust association; however, previous research has focused mostly on pathogen disgust. By measuring the associations between these variables with our measure of sexual disgust, we hope to clarify how conservatism or religious affiliation influences disgust experienced towards specific sexual acts.


5. General discussion
Sexual disgust is an understudied emotion of great importance from
an evolutionary perspective. Previous research suggests there is interesting
individual variation in the activation of this emotion. To
understand how individual variation in sexual disgust sensitivity can
persist under the winnowing forces of sexual selection, we must consider
the role of context and personality dimensions in the conceptualization
of sexual disgust. The primary focus of the studies presented
in this paper was to address the limitations of current measures
of sexual disgust, while systematically creating and testing a novel instrument
for use in future studies.

5.1. Limitations and future directions
The studies presented in this paper have several limitations that
should be considered. First, although our studies attempted to broaden
the age range and demographic distribution of the participants, selection
issues common in psychological research might still be at play.
Recruiting individuals from the university's subject pool is a common,
inexpensive way to increase sample size; however, this often results in a
young, liberal sample. The use of Amazon's Mechanical Turk helps
mitigate this issue, but only participants living in the US with internet
access could participate. Participants were demographically similar
across the three studies in terms of ethnicity, age, and sexual orientation.
However, there was variation between each study, which may
account for differences in results between Studies 2 and 3. We did not
collect data on the political orientation of individuals in Study 1. It is
possible that the individuals who participated in this nomination procedure
are not representative of politically diverse populations that
exist outside of western, economic, industrialized, rich, and democratic
samples (WEIRD; Henrich, Heine & Norenzayan, 2010). Cross-cultural
research is needed to address these issues.
It is also possible that the items generated in Study 1 do not map
exactly onto a functional analysis of sexual disgust during human
evolutionary history, but rather are a better representation of items that
individuals find disgusting within the modern environment. For example,
our measure does not include items about mating with an unattractive
person or someone with cues indicative of disease such as
open lesions, sores, or STIs. These problems, among others not included
on our measure, were presumably important deterrents during the EEA.
Future research could examine if inclusion of such items alters the latent
structure of sexual disgust.
We find it surprising that most of the sex differences that were found
in Study 2 did not replicate in Study 3, except for a significant sex
difference on the “Promiscuity” factor. The other factors of the SDI
should also be relevant for women and men's mating strategies and
should be differentially activated according to the adaptive problem
being represented. This should be especially true for items regarding
incest and rape. We believe this might be because of our sample (majority
of which was obtained through Amazon's Mechanical Turk) and
may not represent the true nature of sex differences in this emotion or
on this measure. Additional research is needed to test the robustness of
sex differences in sexual disgust across factors.
Although the studies presented in this paper provide evidence in
support of previous research relating sexual disgust to various personality
dimensions, we cannot reasonably establish the direction of
causality between these variables. It is not clear, for example, whether
conservative worldviews cause higher levels of sexual disgust or, alternatively,
whether higher levels of sexual disgust lead people to
support conservative worldviews that stigmatize sexual acts. Some links
between sexual disgust and other individual difference variables may
be the result of sexual disgust thresholds creating patterns of thoughts,
feelings, and behavior. Other links may result from pre-existing
personal characteristics—such as immune functioning, relationship
status, or formidability—involved in the calibration of sexual disgust
across development. Future research should work to disentangle the
causality of these relationships.

5.2. Hypothesized functions of the six factors of sexual disgust

Studies 2 and 3 determined a six-factor organization of sexual disgust.
These six dimensions of sexual disgust may map on to solutions to
six partially distinct adaptive problems. Understanding the proper domain
of each facet is of critical importance in predicting and interpreting
individual differences. We have hypothesized the adaptive
function of each factor below. Future research will need to examine
whether the six dimensions of sexual disgust reflect unique adaptations
that evolved in response to different adaptive problems.

5.2.1. Taboo
Engaging in the activities under the “Taboo” factor pose various
social and biological costs. Several of the items within the “Taboo”
factor are considered illegal or unusual across cultures (e.g., rape, sex
with children, sex with animals, sex with the use of human feces) while
others refer to sex with close genetic relatives. Both categories of behaviors
are often moralized and deemed unacceptable by the majority
of people. Engaging in sexual acts deemed unacceptable by one's social
group poses a serious adaptive problem: being socially ostracized.
Experiencing sexual disgust towards these activities might aid in
avoiding behaviors that can lead to social devaluation, alongside prospective
shame (Sznycer et al., 2016). Further, engaging in sex with
genetic relatives can lead to deleterious phenotypic effects in offspring.
Sexual disgust should prevent participation in these acts and promote
negative moralization of individuals who engage in these acts.

5.2.2. BDSM
Items that constitute the “BDSM” factor involve activities that are
potentially violent or dangerous. Although these items have become
less stigmatized over time (Weiss, 2006) they are still considered less
typical sexual activities. It is possible that these items are sexually
disgusting because these activities are triggering our evolved psychology
of punishment or harm avoidance, or because several of the
items represent behaviors commonly used in sexual coercion. Even
though these activities can be completely safe, sexual disgust may
function to reduce participation, thereby decreasing the potential risks
associated with harm.

5.2.3. Same-sex attraction
The “Same-sex attraction” factor may have arisen due to the way
that “disgust interacts with the ‘moral’ system” (Lieberman &
Patrick, 2018, pg. 134). Individuals engaging in sexual activities with
the same-sex have a low expected sexual value for heterosexual individuals,
and are considered a “minority group”. In our ancestral environment,
sexual disgust might have functioned to cognitively label
these individuals to eliminate the costs associated with channeling resources
or time into attempting to mate with such individuals.
Another reason this factor may have emerged centers around the
mental association between short-term mating orientation, promiscuity,
and homosexuality (Pinsof and Haselton, 2017, Pinsof &
Haselton, 2016). We found no evidence to support the idea that shortterm
mating orientation is associated with levels of disgust on the
“Same-sex attraction” factor in these studies. However, we did find that
disgust towards the “Promiscuity” factor was positively, highly correlated
with disgust towards “Same-sex attraction” in Studies 2 and 3.
Future research should work to disentangle potential reasons that this
factor emerged.

5.2.4. Promiscuity
The items that constitute the “Promiscuity” factor represent interest
in sexual variety. By engaging in acts of uncommitted, promiscuous
mating, individuals are at risk of having sex with someone whom will
not continue to be a future sexual partner, signaling themselves as an
unreliable, uncommitted mate to those in the surrounding environment,
or contracting sexually transmitted infections with increased exposure
to sexual partners and activities.
While individuals interested in sexual variety might not consider the
items on this factor overtly sexually disgusting, a potential mate who
engages in these behaviors could be costly as a long-term mate. The
replicable sex difference in levels of disgust experienced by men and
women on this factor may reflect women's desire for committed, longterm
mating as well as the costs women historically incurred from
short-term mating (Buss, 2016; Symons, 1979). Sexual disgust on this
factor should therefore function to deter individuals from facing the
potential social and health risks that are faced when one engages in
promiscuous sex (e.g., reputational damage; contracting a sexually
transmitted disease) and aid in mate selection. Future research should
examine the extent to which disgust towards “Promiscuity” is associated
with sexual regret.

5.2.5. Oral sex
The function of the “Oral sex” factor of the SDI is hypothesized to
deter participation in sexual activities that could lead to increased rates
of transmission of harmful pathogens or diseases, tapping into our
evolved psychology of disease avoidance. Genitals harbor bacteria that
can be dangerous when transmitted to other areas, either orally or
through penile-vaginal penetration (American Sexual Health
Association, 2016; Schneede, Tenke & Hofstetter, 2003). Being disgusted
by cues to increased risk of disease or pathogen transmission by
genital to mouth contact might function to protect individuals from
contracting these diseases.
Disgust towards “Oral sex” is different from disgust towards the
“Promiscuity” factor in several important ways. While it is certainly
true that engaging in promiscuous sex promotes higher disease risk,
there are a variety of other adaptive challenges that are also closely
associated with promiscuity, such as reputational damage and ensuring
investment. This is less true for “Oral sex,” because oral sex consists of
this unique, adaptive problem involving potential disease transmission
from intimate genital to mouth contact. Interestingly, the items that
constitute this factor involve acts of performing oral sex, not receiving.
It remains unclear why this asymmetry exists. Future research should
examine predictors of variation in this facet of sexual disgust.

5.2.6. Hygiene
The extraction of a factor about “Hygiene” is not surprising from an
evolutionary perspective,; but it is particularly interesting because it
provides evidence that within sexual disgust, elements of pathogen
avoidance are critical. Similar to the “Oral sex” factor, disgust towards
these items likely taps into our evolved psychology of disease avoidance.
Avoiding contact with contaminated vectors is of utmost importance
within sexual contexts. Any attempt to decrease exposure to
the pathogens involved in sexual activities would have been advantageous.
Further, bad hygiene might have been a reliable cue to increased
levels of pathogen load during our evolutionary history. Our psychology
should function to deter engaging in sexual activities that
would expose us to harmful diseases or vectors. Sex is already a risky
activity to engage in. If one is disgusted by cues to pathogens, then the
presence of bad breath or bad hygiene should further increase disgust,
inhibiting participation in sexual activities.


Future research should disentangle the adaptive function of each
factor of the SDI. If our speculations are correct, then these factors
could be linked to variation in legal rules or systems, parasite prevalence,
sexual strategies, sexual dysfunction, sexual coercion, or
childhood co-residence.. While the problems associated with the factors
of the SDI should be consistent cross-culturally, varying levels of context-
specific input might result in cross-cultural differences in sexual
disgust activation. Ecologies vary in parasite prevalence, for example,
which may evoke cultural differences in sexual disgust thresholds.
Mating pools vary in operational sex ratio, which may downregulate
“Promiscuity” disgust when there is a surplus of women, which activates
more frequent short-term mating. Cross-cultural research can test
these hypotheses, as well as examine the universality and cultural
specificity of the six factors of sexual disgust discovered in the current
studies.