Sex Differences in Attention to Visual Sexual Stimuli Heather Rupp & Kim Wallen Department of Psychology Emory University & Center for Behavioral Neuroscience Atlanta, GA 1. Cognitive processing of sexual stimuli. 2. Sex differences in neural function and structure. 3. Sex differences in external factors influencing sexual arousal. 4. Hormonal modulation of sexual behavior. 5. Cross-species analogies in sexual behavior and underlying neuroendocrinology.   Previous work w/nonhuman primates, now work a/humans, goal to do cross-species comparisons Today I am going to propose a study to you for my dissertation that aims to investigate sex differences in attention to sexual stimuli.

                                                             We do not know what factors are important for males and females in their interest in sexual stimuli. Common societal opinion may be obvious, however this is not tested or correct! Sex differences in response to visual sexual stimuli are widely acknowledged, although poorly documented (Murnen & Stockton, 1997). Reflected in society and the media is the assumption that males respond more to visual sexual stimuli than do females. Pornographic magazines and videos directed at males are a mulit-billion dollar industry while visual erotica directed towards women is difficult to find. Although experimental studies support the idea that males generally do respond more to sexual stimuli than females do, there is far from a complete understanding of this sex difference (Murnen & Stockton, 1997; Laan, Everaerd, van Bellen, & Hanewald, 1994; Schmidt, 1975; Steinman, et al., 1981). Observed sex differences in the response to visual sexual stimuli may be an evolved trait resulting from sociological or biological influences or their interaction. The extent of sex differences and the exact mechanisms producing them are unclear.

Subjects recruited via email and flyers from Emory University and Georgia State University graduate and professional schools heterosexual preference and some experience with pornography, aged 23-35 15 female on oral contraception (OC) , 15 naturally cycling women (NC) , and 15 males. Females counterbalanced for phase of their menstrual cycle at time of session. Menstrual (1-5) Periovulatory (9-13) Luteal (20-24) Target number is 15 males and 30 females between 23 and 35 years of age. Fifteen women will be on oral contraception and the other 15 will be normal cycling women. heterosexual preference and some experience with pornography

collected from free sites on the internet photos varied on : Activity Stimuli collected from free sites on the internet photos varied on : Activity oral sex to male to female intercourse Female dominant Male dominant all photos pilot tested for sexual attractiveness total of 72 photos randomly viewed at own pace We think that the following three factors may be important to systematically vary in order to understand what is attractive to males and females Perhaps how males and females attend to sexual aspects of pics influences subsequent subjective arousal. For example, females may be more aroused by photos in which faces are visible while males may be more aroused by exposed genitals. Stimuli will be sexually explicit photos of heterosexual couples engaged in oral sex or intercourse. Photos will vary according to line of females gaze, extent of genital exposure, and type of sexual activity. Photos will be paired with another photo, matched for actors and resolution, which differs from the match photo on only one of our variables of interest. Photos will be graphic in nature and taken from the Internet. Photos will be independently rated by seven males and seven females not involved in the study for levels of sexual attractiveness. Based on these pilot ratings, only stimuli not found to be aversive or negative will be included for the experiment. The raters rated 360 images, 15 pairs from each of the sexual categories (6) by the 2 types of categories (zoom, gaze)- edited down to 9 pairs based on ratings Asked to rate stimuli –1, 0, 1-4 For all comparisons, male is sig greater tha female Took top 9 rated pics from 15 by both males and females- if didn’t agree took pic w/highest mean mean There will be 15 pairs of pictures that vary according to gaze and 15 pairs that vary with genital focus. Within each of the 15 pairs, 3 pairs will portray the following activities; oral sex to a male by female, oral sex to a female by male, sexual intercourse with female dominant facing the male, sexual intercourse with female dominant facing away from the male, and male dominant sexual intercourse. This will produce a total of 30 matched pairs for each session. Since there will be three sessions total for each subject, three sets of stimuli will be constructed with the characteristics described above. Subjects will all view the same stimuli as each other during all the sessions. The photos will be randomized for each subject in a unique way, however, by the presentation software to account for order effects. The randomization will be done automatically by the eye tracker software so that no subject will see the same order of stimulus presentation as another subject. So total for the project is 3 Xs 72, or 216 pics.

Measures Dependent View time Whole slide Look zones Independent Sex Contraceptive Use Phase of cycle We think that the following three factors may be important to systematically vary in order to understand what is attractive to males and females Perhaps how males and females attend to sexual aspects of pics influences subsequent subjective arousal. For example, females may be more aroused by photos in which faces are visible while males may be more aroused by exposed genitals. Stimuli will be sexually explicit photos of heterosexual couples engaged in oral sex or intercourse. Photos will vary according to line of females gaze, extent of genital exposure, and type of sexual activity. Photos will be paired with another photo, matched for actors and resolution, which differs from the match photo on only one of our variables of interest. Photos will be graphic in nature and taken from the Internet. Photos will be independently rated by seven males and seven females not involved in the study for levels of sexual attractiveness. Based on these pilot ratings, only stimuli not found to be aversive or negative will be included for the experiment. The raters rated 360 images, 15 pairs from each of the sexual categories (6) by the 2 types of categories (zoom, gaze)- edited down to 9 pairs based on ratings Asked to rate stimuli –1, 0, 1-4 For all comparisons, male is sig greater tha female Took top 9 rated pics from 15 by both males and females- if didn’t agree took pic w/highest mean mean There will be 15 pairs of pictures that vary according to gaze and 15 pairs that vary with genital focus. Within each of the 15 pairs, 3 pairs will portray the following activities; oral sex to a male by female, oral sex to a female by male, sexual intercourse with female dominant facing the male, sexual intercourse with female dominant facing away from the male, and male dominant sexual intercourse. This will produce a total of 30 matched pairs for each session. Since there will be three sessions total for each subject, three sets of stimuli will be constructed with the characteristics described above. Subjects will all view the same stimuli as each other during all the sessions. The photos will be randomized for each subject in a unique way, however, by the presentation software to account for order effects. The randomization will be done automatically by the eye tracker software so that no subject will see the same order of stimulus presentation as another subject. So total for the project is 3 Xs 72, or 216 pics.

MALES did not view the photos as long as OC or NC FEMALES * VIEWING TIME * OC FEMALES viewed the photos longer than NC FEMALES 10 8 6 Seconds Viewed 4 View Time F(2,3011)=46.673; p<.001 males < all female, females on pill longest, NC females in between, all sig diffs, p<.001 effect of sex for females 2 OC NC

VIEWING TIME AND ACTIVITY * OC FEMALES viewed photos of males receiving oral sex shorter than other activities VIEWING TIME AND ACTIVITY * MALES did not view photos of females receiving oral sex as long as did OC or NC FEMALES Oral to Male Oral to Female Intercourse 8 6 Seconds Viewed 4 View Time No significant interaction of sex * activity; F(4,2984)=4.564 No sex diff for oral to male (trend, p=.057, .063) Females viewed OSF longer than males (OCF vs males p=.000; NCF vs males p=.008; trend OCF vs NCF p=.05) OCF viewed longest (vs M/NCF p=.000), males shortest (vs OCF p=.000, vs NCF p=.001) NCF in between No diffs within males 2 OC NC

MALES looked most at Faces and Genitals least at male body and context VIEWING TIME AND LOOK ZONE FEMALES looked most at Genitals least at Context * MALES looked more at face and less at Male Body and Context than FEMALES * Genitals Male Body Female Body Face Context 35 A A A 30 25 20 % Time Fixated in Zone Across sexes…. No difference for genitals No difference for female body Females most at males body (overall effect F(2, )=13.502, p=.000), males vs OCFand NCF p=.000, no diffs females Males more at faces (overall effect F(2, )=3.9, p=.029; vs OCF p=.035, vs NCF, p=.014, no diffs females OCF more at context, (overall F(2, )=11.22, p=.000) vs males and NCF p=.000, no diff males and NCF OCF do not differ from NCF during mens for genitals, FB, MB, face, or context OCF do not differ from NCF during PO for genitals, FB, MB, face or context OCF do not differ from NCF during lut for FB, MB, face during lutNCF look more at genitals than OCF do (p=.012) during lu OCF look more at context than NCF (p=.007) Within…. Males Overall effect of Zone F(4,60)=35.9 p=.000 Genitals more than FB (p=.001), MB (p=.000), and context (.000) FB more than MB (p=.000), less than face (p=.000) and more than context (p=.000) MB less than all but context (no diff), p=.000 Face more than all but genitals (p=.000) Context less than all but MB (p=.000) Within OCF Effect of zone F(4, 50)=39.854, p=.000 No effect of phase or zone*phase interaction OVERALL- all sig different p<.000 ; most genitals, face, FB, MB= Context (all .001 except g vs f, FB vs MB) Same pattern at mens, po, and lut Within genitals, FB, MB, no sig diffs w/phase; for faces look more at lut than PO (p=.026) Within NCF OVERALL effect of phase F(2, 50)=58.2 p=.000 Most at genitals,then face, FB, MB, context (all p=.000 except FB vs MB=.008, FB vs Face=.01) No phase * zone interactionSame pattern at mens, po and lut Within genitals looked more at lut than mens (po = mens, lut) p=.05 No diff for FB, MB, face, 15 10 5 OC NC

MALE OC FEMALE

VIEW TIME AND MENSTRUAL PHASE *** OC FEMALES show more interest in all photos during their menstrual phase ** *** NC FEMALES show more interest in all photos during their periovulatory phase 10 Periovulatory Luteal Menstrual 8 6 Seconds Viewed 4 2 Main efftect of phase ALSO sex * phase interaction F(2, 1929)=44.704; p<.001 WITHIN sexes OC females looked longest at mens (sig from both (p<.001, no diff po/ lut) NC females looked longest at po (p=.009, .000), next at mens (p=.009), least at lut Across sexes At mens, OC females longer than NC female (F(1,645)=10.724; p=.001 At PO. NC female longer than NC females (F(1,719)=14.14; p<.001 At Lut, OC females look longer p=.ooo Mens PO Lut Mens PO Lut OC NC

Conclusions males view shorter MALES and FEMALES do attend differently to visual sexual stimuli males view shorter Observed sex differences vary with content of the stimuli FEMALES prefer photos of oral sex to females MALES look more at faces and less at the male body and context than FEMALES FEMALE interest may vary with steroid hormone levels The cognitive aspect of sexual arousal may be important to consider in the treatment of sexual dysfunction. Males probably look longer due to increased experience and preference for novelty. OC females may have most interest (corroberated by both measures) because they are free from exogenous hormones That NC females look longest but rate lowest during PO may mean that they are choosier (???) or we may have gotten our phased wrong, strong luteal preference could be reflection of delayed ovulation

Acknowledgements Emory University Dr. Kim Wallen Dr. Stephan Hamann Dr. Debbie Mills Dr. Jim Rilling Dr. Hillary Rodman Georgia State University Dr. Kay Beck