Kin Affiliation Across the Ovulatory Cycle

Abstract

A commonplace observation in humans is that close genetic relatives tend to avoid one another as sexual partners. Despite the growing psychological research on how antierotic attitudes develop toward relatives, few studies have focused on actual behavior. One prediction, stemming from parental investment theory, is that women should be more vigilant of reproductioncompromising behaviors, such as inbreeding, during times of peak fertility than during times of low fertility. Indeed, females of other species avoid interactions with male kin when fertile-but the corollary behavior in humans has yet to be explored. Here we fill this gap. Using duration and frequency of cell-phone calls, an objective behavioral measure that reflects motivations to interact socially, we show that women selectively avoid interactions with their fathers during peak fertility. Avoidance specifically targeted fathers, which rules out alternative explanations. These data suggest that psychological mechanisms underlying mating psychology regulate sexual avoidance behaviors, and in women they fluctuate according to fertility status.

Changes in Sleep Time and Sleep Quality across the Ovulatory Cycle as a Function of Fertility and Partner Attractiveness

“…Relatedly, women have been shown to decrease rape-related risky behaviors [15] and increase hand-grip strength in response to hypothetical rape scenarios [16] at high fertility compared to low (but see [17], for a discussion of the effectiveness of these behaviors). Women have also been shown to express greater sexual disgust sensitivity [18] and to selectively reduce affiliation with close male kin, but not close female kin [19] at high fertility relative to low. These patterns have been interpreted as reducing the possibility of reproductively costly scenarios such as inbreeding.…”

Smartphones: A Game Changer for Psychological Research

“…By analyzing these naturalistically observed behaviors, we gain meaningful insight into the psychological state of users. For example, the automatic logs of phone communications (e.g., who, when, how long of calls and text messages) shed important information about the users [3]. Despite the privacy concern of smartphone data, many users still entirely or partially share their information through social media applications like Twitter, Facebook, LinkedIn, etc; Users voluntarily log into such Apps and share their thoughts, feelings, and daily activities.…”

No evidence that inbreeding avoidance is up-regulated during the ovulatory phase of the menstrual cycle

“…Behaviors aimed at reducing opportunities for inbreeding to occur are predicted to increase around ovulation (Lieberman et al, 2011) but have yet to be the focus of large-scale, rigorous tests. To date, the best evidence for ovulatory shifts in inbreeding-avoidance comes from Lieberman et al (2011).…”

“…Behaviors aimed at reducing opportunities for inbreeding to occur are predicted to increase around ovulation (Lieberman et al, 2011) but have yet to be the focus of large-scale, rigorous tests. To date, the best evidence for ovulatory shifts in inbreeding-avoidance comes from Lieberman et al (2011). In a longitudinal study of 48 women's mobile phone records from one menstrual cycle, Lieberman et al reported that women called their fathers less frequently, and spoke to them for less time when they did call them, during the high-fertility phase of the menstrual cycle than when fertility was low.…”

“…The ovulatory phase of the menstrual cycle is characterized by the combination of high estradiol and low progesterone (Gangestad & Haselton, 2015). Thus, if Lieberman et al (2011) are correct that ovulation increases inbreeding-avoidance behaviors, we would expect preferences for self-resembling male, but not selfresembling female, faces to decrease when estradiol is high and progesterone is simultaneously low.…”