McKibbin, W.F., Bates, V.M., Shackelford, T.K., Hafen, C.A., & LaMunyon, C.W. (2010). Risk of sperm competition moderates the relationship between men’s satisfaction with their partner and men’s interest in their partner’s copulatory orgasm. Personality and Individual Differences, 49, 961-966

Risk of sperm competition moderates the relationship between men’s satisfaction with their partner and men’s interest in their partner’s copulatory orgasm

William F. McKibbin, Vincent M. Bates, Todd K. Shackelford,
Christopher A. Hafen, and Craig W. LaMunyon


Sperm competition occurs when the sperm of multiple males concurrently occupy a female’s reproductive
tract and compete for fertilization. Sperm competition may have been a recurrent adaptive problem over human evolutionary history (Shackelford & Pound, 2006). Women’s orgasm may facilitate selective uptake and retention of a particular man’s sperm (Thornhill & Gangestad, 2008). Men who are more satisfied with and invested in their relationship may experience greater costs in the event of sperm competition and potential cuckoldry. Therefore, these men may be especially interested in ensuring their partner’s copulatory orgasm. We hypothesized that men’s relationship satisfaction and investment would predict interest in their partner’s copulatory orgasm, and that sperm competition risk would moderate the association between relationship satisfaction and interest in partner’s copulatory orgasm. Using structural equation modeling on self-report data secured from 229 men in a committed heterosexual relationship, we tested and found support for these hypotheses.

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Swami, V., … McKibbin, W.F., et al. (2010). The attractive female body weight and female body dissatisfaction in 26 countries across 10 world regions: Results of the International Body Project I. Personality and Social Psychology Bulletin, 36, 309-325

The Attractive Female Body Weight and Female Body Dissatisfaction in 26 Countries Across 10 World Regions: Results of the International Body Project I

Viren Swami, David A. Frederick, Toivo Aavik, Lidia Alcalay, Jüri Allik, Donna Anderson, Sonny Andrianto, Arvind Arora, Åke Brännström, John Cunningham, Dariusz Danel, Krystyna Doroszewicz, Gordon B. Forbes, Adrian Furnham, Corina U. Greven, Jamin Halberstadt, Shuang Hao, Tanja Haubner, Choon Sup Hwang, Mary Inman, Jas Laile Jaafar, Jacob Johansson, Jaehee Jung, Askin Keser, Uta Kretzschmar, Lance Lachenicht, Norman P. Li, Kenneth Locke, Jan-Erik Lönnqvist, Christy Lopez, Lynn Loutzenhiser, Natalya C. Maisel, Marita P. McCabe, Donald R. McCreary, William F. McKibbin, Alex Mussap, Félix Neto, Carly Nowell, Liane Peña Alampay, Subash K. Pillai, Alessandra Pokrajac-Bulian, René T. Proyer, Katinka Quintelier, Lina A. Ricciardelli, Malgorzata Rozmus-Wrzesinska, Willibald Ruch, Timothy Russo, Astrid Schütz, Todd K. Shackelford, Sheeba Shashidharan, Franco Simonetti, Dhachayani Sinniah, Mira Swami, Griet Vandermassen, Marijke van Duynslaeger, Markku Verkasalo, Martin Voracek, Curtis K. Yee, Echo Xian Zhang, Xiaoying Zhang and Ivanka Zivcic-Becirevic


 This study reports results from the first International Body Project (IBP-I), which surveyed 7,434 individuals in 10 major world regions about body weight ideals and body dissatisfaction. Participants completed the female Contour Drawing Figure Rating Scale (CDFRS) and self-reported their exposure to Western and local media. Results indicated there were significant cross-regional differences in the ideal female figure and body dissatisfaction, but effect sizes were small across high-socioeconomic-status (SES) sites. Within cultures, heavier bodies were preferred in low-SES sites compared to high-SES sites in Malaysia and South Africa (ds = 1.94-2.49) but not in Austria. Participant age, body mass index (BMI), and Western media exposure predicted body weight ideals. BMI and Western media exposure predicted body dissatisfaction among women. Our results show that body dissatisfaction and desire for thinness is commonplace in high-SES settings across world regions, highlighting the need for international attention to this problem.

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