TABLE 3 Significant predictors of average activation in ROIs. Average Activation Response E P T (free/total) SIS1 SIS2 SES SOI Insula + Superior Temporal Gyrus + - Precentral Gyrus - - / + + + Posterior Cingulate Cortex + - + Parahippocampal Gyrus - + + Anterior Cingulate Cortex + / Parietal Cortex (BA40) - + +=significant positive predictor, -=significant negative predictor.

Women’s Neural Activation in Response to Masculinized versus Feminized Male Faces: Mediation by Hormones and Women’s Neural Activation in Response to Masculinized versus Feminized Male Faces: Mediation by Hormones and Psychosexual Factors Psychosexual Factors

Heather A. RuppHeather A. Rupp1,21,2 , , Thomas W. JamesThomas W. James33, , Ellen D. KettersonEllen D. Ketterson22, Dale R. Sengelaub, Dale R. Sengelaub33, Erick Janssen, Erick Janssen1,31,3, & Julia R. Heiman , & Julia R. Heiman 1,31,3

1. The Kinsey Institute for Research in Sex, Gender, and Reproduction, Indiana University, Bloomington, IN, 47405.2. Department of Biology, Indiana University, Bloomington, Indiana 47405.

3. Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405.

INTRODUCTION• Mate choice is a complex decision with high potential risks for women. Because male traits generally thought to predict good condition and even physical quality often coincide with less desirable social characteristics, women must balance potentially disparate mating priorities. For example, although men characterized by more masculine testosterone-linked traits may be socially dominant and sire more offspring, they are also less likely to invest in offspring and to enter into a partnered relationship.

• Women’s evaluations of potential mates are thought to integrate physiological and social information to determine the appropriateness of a man as a sexual partner. Facial cues of masculinity have been previously demonstrated to be salient cues of risk and reward for women in their assessment of men as potential sexual partners.

• Preferences for facial masculinity fluctuate across the menstrual cycle in parallel with changes in hypothesized reproductive priorities. Around the time of ovulation, when conception is likely, women may be more responsive to cues that predict physical mate quality, specifically traits indicating increased androgens, leading to a preference for masculine facial features traits that are not favored during other phases.

• While the literature strongly supports an association between hormonal state and women’s preferences for more or less masculine men, little is known about how hormones mediate women’s mate choice preferences. We hypothesized that hormones mediate the perception and evaluation of male faces. We expected increased activation in areas related to risk, face processing, and reward in response to masculinized versus feminized faces, and for this difference to be larger during the follicular versus luteal phase.

METHODSParticipants• Twelve heterosexual women, between 23 and 28 years of age, not currently in a committed relationship, with regular menstrual cycles, and not using hormonal contraceptives or medication for depression or anxiety participated in this study.

Data Collection• All participants attended two test sessions. Females were tested in a balanced order during their follicular (cycle days 10-12) and luteal (19-23) phases of their menstrual cycle. At the start of each session blood was taken for measurement of estradiol, progesterone, and testosterone.

• Participants completed a series of questionnaires regarding their psychosexual profiles, including the Sociosexual Orientation Inventory (SOI; Simpson & Gangestad, 1991) and the Sexual Inhibition/Sexual Excitation Scales (SIS/SES,Janssen et al., 2002).

• While in the fMRI scanner (3 Tesla, Siemens), subjects viewed photographs of male faces presented in a rapid event related design (TR=2 seconds). Pictures were of male faces masculinized and feminized using a computer software program (Psychomorph, Rowland & Perrett, 1995). Fifty-six male face picture pairs were created (30% feminized, 30% masculinized) to produce a total 112 male face pictures, each presented twice for a total of 224 photos. Photos were presented across 8, 5 minute runs.

• Pictures were shown individually for 4 s with a variable ISI of 2, 4, or 6 secs.

Data Analysis• fMRI data underwent motion correction, slice scan-time correction, spatial smoothing, and linear trend removal. They were co-registered to high-resolution structural volume and normalized into Talairach space.

• Random-effects model analyses were used to examine main effects of facial masculinity and interactions with menstrual phase at a threshold of p<.05 using a cluster threshold correction of 10 voxels (270 mm).

• A priori regions of interest (ROIs) selected from the whole-brain SPM analysis were further analyzed by extracting estimated timecourses using a deconvolution analysis on each individual. BOLD response peak (beta weights) between six to 10 seconds after stimulus onset. Peak BOLD response was then entered as the dependent measure for linear regression analyses with hormone levels (estradiol, progesterone, free testosterone, and total testosterone) and psychosexual profiles (SES, SIS1, SIS2, SOI).

DISCUSSION• This fMRI study is the first, to our knowledge, to describe neural activation in women evaluating potential sexual partners, and specifically comparing neural activation to masculinized versus feminized male faces.

• We found seven brain regions related to face, reward, and risk-processing that responded more to the masculinized than to the feminized faces.

• Increased activation in the anterior cingulate cortex and insula, specifically, may indicate that women perceive masculinized faces to be both more risky and more attractive than feminized faces.

• Patterns of neural activation in these regions were predicted by participants’ hormone levels and psychosexual traits.

• The patterns of hormonally and psychosexually mediated neural activation observed in the current study may offer insight into the cognitive processes underlying women’s behavioral partner preferences

CONCLUSIONSThe current study points towards enhancements of both sensory discrimination and reward processing around ovulation in response to masculine faces as possible mediators of women’s behavioral mate preferences.

ACKNOWLEDGEMENTSThe authors thank Dr. David Perrett and The Perception Laboratory for use of the Psychomorph software. We would also like to thank Dr. Ronald McClintock and the GCRC for hormone assays (GCRC Grant: M01 RR00750). Finally we gratefully acknowledge Sunah Kim and Ryan Stevenson for programming, analysis, and technical help. This work was supported by the NIH funded Common Themes in Reproductive Diversity training grant NICHHD-T32-HD-49339-0.REFERENCESJanssen, E., Vorst, H., Finn, P., & Bancroft, J. (2002). The sexual inhibition (SIS) and sexual excitation (SES) scales: I. Measuring sexual inhibition and excitation proneness in men. Journal of Sex Research, 39, 114-126.Perrett. D. I., Lee, K. J., Penton-Voak, I., Rowland, D., Yoshikawa, S., Burt, D. M.., Henzi, S. P., Castles, D.L., & Akamatsu, S. (1998). Effects of sexual dimorphism on facial attractiveness. Nature, 394, 884-887.Simpson, J. A., & Gangestad, S. W. (1991). Individual differences in sociosexuality: evidence for convergent and discriminant validity.

Journal of Personality and Social Psychology, 60, 870-883.

RESULTS

OCCOCC

Masculinized Feminized

“How likely would you be to have sex with the man presented?”

• Participants’ subjective evaluations of likelihood of having sex with the men presented did not differ by menstrual cycle phase or masculinity of the faces (Mean ± SD=1.92±.29).

Overall, we observed increased activation in response to masculinized versus feminized faces in the right insula, right

precentral gyrus, right superior temporal gyrus, posterior cingulate cortex, and the right parahippocampal gyrus.

52, 8, 10 8101010

• There were no areas of increased activation to feminized versus masculinized faces during the follicular phase. Contrasts within the luteal phase did not demonstrate any differences in activation between masculinized and feminized faces.

Figure 3.

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The regression analyses demonstrated that the degree of overall activation in these brain regions was predicted by participants’ hormone levels and psychosexual factors.

Activation in the parietal cortex (BA40) predicted participants subjective ratings of feminized faces.

During the follicular phase, we observed increased activation in response to masculinized versus feminized faces in the anterior cingulate cortex, parietal cortex, and

the left superior temporal gyrus.

-1, -32, 36 -55, -32, 226, 20, 29 -1, -32, 36 -55, -32, 226, 20, 29