Interpersonal behavior in women: Association with prenatal exposure to sex hormones

Michelle Spix,Marije Aan Het Rot

doi:10.1016/j.paid.2020.110379

Michelle Spix, Marije Aan Het Rot

Open Access

https://doi.org/10.1016/j.paid.2020.110379

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Abstract

The ratio between the second and fourth digit of the hand (2D:4D ratio) has been used as a marker of prenatal exposure to sex hormones. A previous study found that men with smaller 2D:4D ratios, relative to men with larger ratios, were more agreeable and less quarrelsome with women than with men. We aimed to replicate this study, using a similar procedure for sampling interpersonal behaviors but including participants who were first-year students (n = 81) rather than working adults in a long-term romantic relationship. Event-contingent recording of everyday social interactions yielded data on agreeableness, quarrelsomeness, dominance, and submissiveness in different social contexts (e.g., with male vs. female interaction partners). While we did not replicate the findings previously obtained in men, this might be due to the relatively low number of male participants. Female participants with larger 2D:4D ratios were more agreeable with women than with men; this was not found among women with smaller ratios. Future studies on the link between the 2D:4D ratio and interpersonal behavior should consider with whom interactions take place and examine additional factors such as participants' relationship status and hormonal contraceptive use.

Highlights

Prenatal exposure to sex hormones shapes brain development (McEwen & Milner, 2017)
It was suggested that men exposed to more testosterone prenatally are more masculine and more motivated to connect with women
Unlike Moskowitz et al (2015), whose participants were working adults in long-term heterosexual relationships, we studied first-year students who varied in their relationship status

Summary

Introduction

An easy-to-measure marker of prenatal testosterone relative to estrogen exposure is the 2D:4D ratio, representing the length of the second digit relative to the length of the fourth digit. Men generally have smaller ratios than women, indicating higher prenatal testosterone exposure (Manning, 2011). Within-gender variation in the 2D:4D ratio has been linked to within-gender variation in interpersonal functioning. Moskowitz et al (2015) found that while men were generally more agreeable and less quarrelsome towards women than towards other men, this was true for men with smaller 2D:4D ratios. Associations between 2D:4D ratios and interpersonal behaviors were not significant in women. It was suggested that men exposed to more testosterone prenatally are more masculine and more motivated to connect with women.

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