New research indicates that several factors, including relationship instability in childhood, influence how individuals’ emotionally respond to casual sexual experiences. The findings have been published in Evolutionary Psychological Science.

“There has been a lot of interest in studying the sexual behavior of young adults (especially college students) and how that sexual behavior may (or may not) be changing. A lot of the research on this topic has focused on investigating sex differences between males and females when it comes to engaging in (and reacting to) casual sex experiences, including some of our own previous work,” explained study author Jessica A. Hehman, an associate professor of psychology at the University of Redlands.

“To us, though, there seemed to be two holes in the literature, in terms of: (1) investigating individual differences that may account for the large amount of within sex variability that has been found in previous studies; and (2) being limited (mostly) to casual sexual behavior in college students.”

“Therefore, we attempted to address those holes in the literature by investigating two questions: (1) What other factors (i.e., other than being male or female) influence the number of casual sexual partners one has as well as their reactions to casual sex encounters? and (2) Do the previous findings of sex differences in engaging in (and reacting to) casual sex extend to adults outside of a college campus and across the lifespan, or are they specific to young adult college students?”

The researchers surveyed 165 college students (average age 19) and 123 non-students (average age 33) regarding their early-life history, sexual behavior, emotional reactions to casual sex, and other factors.

Unsurprisingly, having long-term relationship goals was associated with negative emotional reactions to casual sex. “Regardless of life stage, engaging in casual sex in the hopes that the relationship will become long-term leads to more negative responses to the experience for both males and females,” Hehman explained.

In line with previous studies, the researchers also found that women in both samples reported feeling more vulnerable and had more concern about their partners’ feelings for them following casual sex compared to men.

“There are sex differences in casual sexual behavior — men tend to have more casual sex partners than women, and women tend to react more negatively to casual sex experiences than men — but there are a lot of within sex differences in how much casual sex men and women engage in as well as how they react to those experiences,” Hehman told PsyPost.

“Individual differences that explain some of that within sex variability include individuals’ own life stage as well as their motivation for engaging in casual sex.”

“For our sample of younger adult college students, early environmental cues of relationship instability (e.g., growing up in a father absent home) explains most of the variance in the positive vs. negative responses to casual sex; whereas, in the older community sample, motivation for engaging in casual sex that is not aligned with the behavior (specifically, engaging in casual sex in the hopes that it will turn into a long-term relationship) explains most of the variance in the responses to casual sex,” Hehman said.

“Therefore, in addition to evidence suggesting the sex difference observed in casual sexual behavior may be life-stage specific, there is also evidence that the factors that influence emotional reactions to that behavior are also life-stage specific.”

As with all research, the study has a few caveats.

“We asked participants to reflect back on their casual sex experiences and report the degree to which they engaged in casual sex with the hopes it would turn into a long-term relationship. The problem is that, in retrospect, participants may not have accurately reported their intentions going into the casual sex experience. That is, while ruminating over their past casual sex experiences, individuals may have protected themselves from negative psychological consequences of their unsuccessful attempts to use casual sex to obtain a long-term mate by using self-deception,” Hehman explained.

“Similarly, we used father absence during development as a potential cue to relationship stability, but there are many other factors in one’s early environment that may contribute to evaluations of what to expect in future relationships. Future research should investigate other possible environmental cues, such as the quality of familial relationships, parents’ mental health, substance abuse, and levels of conflict within the household.”

“Also, in order to truly investigate whether casual sex behavior and the reactions to that behavior are life-stage specific, longitudinal studies following the same individuals over time are needed to see how their behavior and reactions change with age,” Hehman said.

The study, “Beyond Sex Differences: Predictors of Negative Emotions Following Casual Sex“, was authored by Jessica A. Hehman and Catherine A. Salmon.