Tendencies to fall asleep first after sex are associated with greater partner desires for bonding and affection

Despite the large literature on human reproductive strategies, research on psychology and behavior following acts of sex is scarce. The Post-Coital Time Interval (PCTI) may be particularly important for pair bonding and establishing relationship commitment. This study examined how desires for long-term partner expressions of affection and emotional bonding relate to self-reports of sleep onset patterns between couples. We also examined whether sex differences existed in self-reports of sleep onset following sexual intercourse versus when falling asleep together after not engaging in sex. Participants (N = 456) completed an online inventory assessing bonding, affection, communication, focus of attention, satisfaction, and responsiveness during the PCTI and reported their perceptions of relative sleep onset after having sex and when not having sex. Participants' desires for partner expressions of emotional bonding, physical affection, and communication were higher when their partners' had greater tendencies to fall asleep first after sex. In contrast, responses to comparison items (e.g., humor) did not exhibit this effect. Men reported that their partners were more likely to fall asleep first when going to bed without having sex, but there was no sex difference in reports of relative sleep onset after having sexual intercourse.