Differential Effects of Male vs Differential Effects of Male vs. Female Pheromones on Attraction to Physical, Emotional, Sexual, and Interpersonal Traits. Bjornsen, C. A., Curtin, L. J., Hanna, Z. S., Johnson, S. A., Klineburger, P. C., Raines, M. T., & Spiers, J. H. Longwood University, Virginia, U.S.A. 1. Face Chosen x Cycle Phase - cubic p.<.05 4. Career Aptitude Scale x Cycle Phase –cubic p.<.05 Abstract Expanding upon previous work, we examined the effects of exposure to three different putative human pheromones upon male and female mate preferences. Results indicate sex differences in the influence of pheromones, and ovulatory cycle phase, upon mate selection and attraction. These findings relevance of these findings to our understanding of the development of young adults’ mate selections and intimate relationships. Methods Participants were male (n = 32, M age = 19.3) and female (n = 40, M age = 19.1) University students. Female participants were not using hormonal birth control, and self-reported ovulatory cycle phase was recorded during four laboratory visits. Employing a double-blind method, participants visited our laboratory individually on four occasions during a one-month period, at exactly one-week intervals. Females were exposed to only one stimulus on all four trials (either estratetraenol (n = 18) or androstadienone (n = 22), and were interviewed by the same female researcher each visit. Males were exposed to a different stimulus each visit (in a randomly counterbalanced order), and were interviewed by the same male researcher each visit. The four stimuli were (a.) the control stimuli: propylene glycol (PG), (b.) androstadienone (0.00025 M concentration in PG); (c.) androsterone (1 mg/ml concentration in PG), and (d.) estratetraenol (0.00025 M concentration in PG). Androstadienone and androsterone are synthetic male pheromones, and estratetraenol is a synthetic female pheromone. The pheromone concentrations were designed to be consciously undetectable, following Jacob and McClintock (1999). At the beginning of each lab visit, a Band-Aid containing the liquid stimulus was placed on the philtrum (between the upper lip and nose) of the participant. If the participant was a female, she and the researcher determined the ovulatory cycle day, based on the first or last day of the most recent menstrual period. Five minutes after the stimulus had been placed under the nose, the participant watched a “face-morph” video program developed by Victor Johnston (www.psych.nmsu.edu/~vic). This computer program shows a human face changing slowly from a “highly masculine” face to a “neutral” face to a “highly feminine” face (see Figure 2 below). After watching the entire 1-minute video, the participant was asked to play the video forward and backward until he or she saw the face that was “most attractive or appealing” to the participant. After selecting the most attractive face, the participant was asked to rate the “person” selected on the following 21 characteristics: Can succeed in a career Is emotionally stable Is ambitious Is agreeable Is good with children Has a sense of humor Is handsome, good-looking Is expressive, open Is intelligent Is a good conversationalist Is outgoing and sociable Is sexually attractive Can make a lot of money Is athletic Is kind Is confident and assertive Is experienced with relationships Is understanding, sympathetic Is skilled as a lover I would like to have a short-term relationship with the person Results and Discussion Results were analyzed using individual items as dependent variables, masculinity/femininity scores of most attractive face choices per lab visit, as well as by the following scales, which were obtained through factor analysis: Career Ability: career, ambitious, intelligent, money, confident Emotional Ability: stable, children, kind, sympathetic, longterm Social Skills: agreeable, humor, expressive, conversationalist, sociable Sexually Attractive: handsome, shortterm, sexually, athletic, experienced, lover Analyses were calculated separately for females and males. For females, doubly multivariate mixed model repeated measures ANOVAs were employed, with pheromone (androstadienone vs. estratetraenol) serving as a between-subjects variable, and cycle phase (menstrual, follicular/ovulatory, early luteal, late luteal) serving as a within-subjects variable. For males, repeated measures ANOVAs were employed, with pheromone (control, estratetraenol, androstadienone, and androsterone) serving as a between-subjects variable.Results that were found to be statistically significant are depicted in the graphs to the right. Females: 1. Females were more likely to choose a “more masculine” face during the menstrual and early luteal phases of the ovulatory cycle. This finding contradicts previous findings that females are more likely to choose a more masculine partner during the ovulatory phase (cites). 2. Females exposed to estratetraen rated selected “males” higher on the scale of social skills during the early luteal phase. 3. Females rated selected “males” as more sexually attractive during the menstrual and (especially) follicular-ovulatory phases than luteal phases. 4. Females were more likely to assign high career aptitude scale scores to the selected “male” during the menstrual and early luteal phases. 5. Females were more likely to state the chosen “male” could succeed in a career during the menstrual and early lutual phases. 6. Females were more likely to state the chosen “male” was confident and assertive during the menstrual phase. Males: 7. Males rated chosen “females” higher on social skills scale scores when exposed to estratetraenol and androstadienone than control and androsterone. 8. Males rated chosen “females” more sexually attractive when exposed to androstadienone than other stimuli. Menstrual Foll-Ovu Early Luteal Late Luteal Menstrual Foll-Ovu Early Luteal Late Luteal Introduction STUDY TWO TEXT A growing body of research indicates that human pheromones may have an important influence on a range of human characteristics, although exactly how, and how strongly, such chemicals produce their effect is yet to be discovered. Nonetheless, human pheromones have been shown to reduce negative and increase positive moods (Grosser et al., 2000; Jacob & McClintock, 2000; Jacob et al, 2001; Jacob & McClintock, 2002), and affect sexual attraction and behavior (Cutler, 1987; Cutler, 1999; Cutler & Stine, 1988; McCoy & Pitino, 2002; Thorne et al., 2002). Researchers have also discovered that, not only does ovulatory phase affect females’ attraction to males (Thornhill & Gangestad, 1999), females exhibit more positive reactions to male pheromones during ovulation (Grammer, 1994). Females who were ovulating were found to indicate a preference for a short-term relationship with a “highly masculine” male, and this preference was more pronounced among females exposed to a human pheromone (Bjornsen et al., 2003). The present study is the second in a series of experiments designed to examine the influence of ovulatory cycle phase and putative human pheromones on mate selection and attraction. Only data from a group of regularly menstruating females who were not using hormonal birth control are presented here. 2. Social Skills Scale x Cycle Phase – quad interaction p.<.05 5. Successful Career x Cycle Phase – cubic p.<.05 Menstrual Foll-Ovu Early Luteal Late Luteal Menstrual Foll-Ovu Early Luteal Late Luteal 3. Sexually Attractive x Cycle Phase - linear p.<.05 6. Confident and Assertive x Cycle Phase – linear p.< .01 Figure 1. Ovulatory Cycle Phase Record Menstrual Foll-Ovu Early Luteal Late Luteal Menstrual Foll-Ovu Early Luteal Late Luteal 7. Social Skills Scale x Pheromone - quad p<.05 8. Sexually Attractive x Pheromone - quad .01 Figure 2. Morphing Facial Images Control Estratetraenol Androstadienone Androsterone Control Estratetraenol Androstadienone Androsterone 20 18 16 14 12 10 8 6 4 2 2 4 6 8 10 12 14 16 18 20 Poster presented August 2005 at the XIIth European Conference on Developmental Psychology, Tenerife, Spain