The behavioral immune system is an evolved adaptation comprised of automatic behavioral, cognitive, and affective reactions that has allowed humans throughout evolutionary history to avoid situations that risk infection by pathogens (e.g., physical proximity to sick people). Although behavioral immune system activation may be functional by helping people avoid such situations, experiencing these automatic reactions during sexual interactions may undermine people’s evaluations of those interactions because sex requires close physical contact. We examined whether two sources of behavioral immune system activation (daily concern over contracting COVID-19 and individual differences in infection concern) undermined satisfaction with sex among 318 partnered adults in the U.S. during the COVID-19 pandemic. Participants reported individual differences in perceived infectability and then, every night for two weeks, reported their (a) daily concern about contracting COVID-19, (b) daily stress, (c) whether they had sex with their partner, and (d) their satisfaction with sex when it occurred. People’s perceived infectability moderated the association between their daily concern about contracting COVID-19 and the extent to which they enjoyed sex when it occurred, such that people higher, but not lower, in perceived infectability enjoyed sex less on days that they were more worried about contracting COVID-19 than usual. This effect was not moderated by biological sex and remained significant when controlling for biological sex, age, relationship length, and frequency of sex. Results highlight the importance of the behavioral immune system to sexual functioning and suggest a novel avenue through which the COVID-19 pandemic has disrupted relationships.

行为免疫系统是一种进化适应，包括自动的行为、认知和情感反应，它允许人类在整个进化历史中避免可能被病原体感染的情况（例如，身体靠近病人）。虽然行为免疫系统激活可能通过帮助人们避免这种情况而发挥作用，但在性互动中经历这些自动反应可能会破坏人们对这些互动的评估，因为性需要密切的身体接触。我们检查了行为免疫系统激活的两种来源（对感染 COVID-19 的日常关注和对感染关注的个体差异）是否会破坏 COVID-19 大流行期间美国 318 名合作成年人对性的满意度。参与者报告了感知传染性的个体差异，然后，每晚两周，报告他们 (a) 对感染 COVID-19 的日常担忧，(b) 日常压力，(c) 他们是否与伴侣发生性关系，以及 (d)他们对性发生时的满意度。人们感知到的可传染性缓和了他们对感染 COVID-19 的日常担忧与他们在发生性行为时享受性生活的程度之间的关联，因此感知可传染性较高但不是较低的人在他们更担心的日子里享受性生活的次数较少比平时感染 COVID-19。这种效应不受生理性别的影响，并且在控制生理性别、年龄、关系长度和性频率时仍然显着。