PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of comintbioLink to Publisher's site
 
Commun Integr Biol. 2010 May-Jun; 3(3): 282–283.
PMCID: PMC2918777

Curvaceous female bodies activate neural reward centers in men

Abstract

Facial symmetry, masculinity and shoulder-to-hip ratios in men convey information to mates about reproductive/genetic quality, the so-called “good genes” hypothesis. On the other hand waist-to-hip ratio conveys important reproductive information about women to men. Here using fMRI, men showed activation in neural reward centers when they viewed and rated the attractiveness of surgically optimally configured female bodies.

Key words: evolutionary biology, neuroscience, human behavior, waist-to-hip ratio (WHR), sexual selection, mate choice

Physical attractiveness serves as a biologically honest signal to members of the opposite sex and is a key element of successful mating and reproduction. Women rate men with masculine, symmetrical faces as more attractive mates than men with feminine and asymmetrical faces. Women also rate men with a high shoulder-to-hip ratio (SHR) as attractive. Attraction to symmetrical and masculine faces, and high SHR males appears to be tightly linked to ovulation in women supporting the idea that these characteristics indicate “good genes”.17

The ability to differentiate the virile from weak is not limited to the female sex; men similarly identity fertile and healthy mates based on morphology. Men prefer women with lower waist-to-hip ratio (WHR) because this is positively correlated with “good genes” indicators. For example, lower WHR women are at a lower risk of developing heart disease, cancer and depression, in addition to having healthier full-term pregnancies and complication- free deliveries when compared to high WHR women. It is well known that optimal WHR is rated as attractive, the world over,811 but the proximate neural mechanisms are not at all understood. In this study,12 we hypothesized that optimal WHR in women would activate neural reward centers men. Specifically, we anticipated activation in reward centers that that have been linked to sexual reward (pleasure) in species with low conception rates (e.g., nucleus accumbens).

Pre- and post-surgical pictures of 7 naked female bodies were shown to 14 men (Mage = 25.21, S.D. = 6.30). Female subjects in the pictures had undergone an elective cosmetic surgery to optimize their WHR. Pre-surgical pictures show a variety of body types from the well-known pear and apple shape to an ectomorphic tube shape. Post-surgery, all 7 bodies displayed the optimized WHR with well-defined buttocks, smaller waists and proportioned thighs: the perfect hour-glass shape.

Images of the rear and oblique rear position of the pre- and post-surgical females served as the stimuli for male participants. These images were randomly presented to male participants 15 times for 1 second with variable interstimulus intervals (2–15 s). Participants used a 5 button fMRI-compatible response pad to rate each picture on attractiveness from very unattractive to very attractive.

Surprisingly, changes in body mass index (BMI) only activated low-level visual areas, while changes in WHR activated areas associated with pleasure, reward13,14 and judgment.15,16 Viewing post-surgical (i.e., optimally designed WHR) bodies revealed activation in the right orbital frontal cortex (OFC), lateral occipital cortex, and the anterior cingulate gyrus. Further examination of OFC activation revealed that the left and right OFC became activated with the post-surgical and not the pre-surgical pictures. Finally, participant’s ratings of attractiveness were regressed on their brain activation for postsurgical (optimal WHR) body images and we found activation in subcortical brain substrates associated with reward, namely the nucleus accumbens. The nucleus accumbens is highly sensitive to rewards and is the seat of addictive behavior. This suggests that men see optimally designed women’s bodies as highly rewarding; neurologically they likely stimulate appetitive, sexual behaviors. We can assume from these findings that so long as WHR hovers around the optimal 0.7, a woman’s BMI can vary without compromising her attractiveness to men.

Footnotes

References

1. Gangestad SW, Cousins AJ. Adaptive design, female mate preferneces and shifts across the menstrual cycle. Ann Rev Sex Res. 2001;12:145–185. [PubMed]
2. Gangestad SW, et al. Changes in women’s mate choice preferences across the menstrual cycle. J Person Soc Psychol. 2007;92:151–163. [PubMed]
3. Hughes SM, Dispenza F, Gallup JGG. Ratings of voice attractiveness predict sexual behavior and body configuration. Evol Human Behav. 2004;25:295–304.
4. Hughes SM, Gallup GGJ. Sex differences in morphological predictors of sexual behavior: Shoulder to hip and waist to hip ratios. Evol Human Behav. 2003;24:173–178.
5. Penton-Voak IS, et al. Menstrual cycle alters face preference. Nature. 1999;399:741–742. [PubMed]
6. Thornhill R, Gangestad SW. Facial attractiveness. Trends Cogn Sci. 1999;3:452–460. [PubMed]
7. Thornhill R, Grammer K. The body and face of woman: one ornament that signals quality? Evol Human Behav. 1999;20:105–120.
8. Furnham A, Moutafi J, Baguma P. A cross-cultural study on the role of weight and waist-to-hip ratio on female attractiveness. Personal Individual Differ. 2002;32:729–745.
9. Singh D. Female mate value at a glance: relationship of waist-to-hip ratio to health, fecundity and attractiveness. Neuro Endocrinol Lett. 2002;23:81–91. [PubMed]
10. Sugiyama LS. Is beauty in the context-sensitive adaptations of the beholder? Shiwiar use of waist-tohip ratio in assessments of female mate value. Evol Human Behav. 2004;25:51–62.
11. Swami V, et al. Preferences for female body size in Britain and the South Pacific. Body Image. 2007;4:219–223. [PubMed]
12. Platek SM, Singh D. Optimal waist-to-hip ratios in women activate neural reward centers in men. PLOS One. 2010;5:9042. [PMC free article] [PubMed]
13. Berns GS, et al. Predictability modulates human brain response to reward. J Neurosci. 2001;21:2793–2798. [PubMed]
14. Platek SM, Krill AL, Wilson B. Implicit trustworthiness ratings of self-resembling faces activate brain centers involved in reward. Neuropsychologia. 2009;47:289–293. [PubMed]
15. Platek SM, Keenan JP, Mohamed FB. Sex differences in the neural correlates of child facial resemblance: an event related fMRI study. NeuroImage. 2005;25:1336–1344. [PubMed]
16. Platek SM, Kemp SM. Is family special to the brain? An event-related fMRI study of familiar, familial and self-face recognition. Neuropsychologia. 2009;47:849–858. [PubMed]

Articles from Communicative & Integrative Biology are provided here courtesy of Taylor & Francis