Michelle, Kyle P, Ellen

1. Women’s Probability of Conception Is Associated with their Preference for Flirtatious but not Masculine Facial Movements (Morrison et al, 2009) Michelle, Kyle P, Ellen

2. Introduction • Depending on the stage of a women’s menstrual cycle, preferences in women’s behaviors change • Height (Pawlowski & Jasienska, 2005) • Voice pitch (Feinberg et al., 2006) • Odor (Gangstad & Thornhill, 1998) • Facial symmetry • During the fertile window, women prefer more masculine faces (Johnston et al., 2001)

3. Introduction • Traits related to testosterone thought to signal immunocompetence (Folstad & Karter, 1992) and developmental health • Height, voice pitch, facial structure • Good genes may indicate a good quality mate, it could also indicate negative personality attributes (Perrett et al., 1998) • Coldness, dishonesty, less parental investment • High quality but high risk mate • Ovulatory shifts in preference leads to trading off traits depending on chance of conception

4. Introduction • Flirting can also signal reward for invested mating effort (Mishra, Clark, & Daly, 2007) • Signals interest to a women, who can be time-strained by fertility windows • Limited by whether or not using static stimuli or dynamic video • Because flirtatious displays are dynamic in nature, attractiveness ratings do not necessarily correlate (Lander, 2008)

5. Introduction • Hypothesis (1): female preferences for masculine movement should be higher in the follicular phases of the menstrual cycle • Hypothesis (2): female preferences for flirtatious facial movement should be more important when chance of conception is highest • Signals reward for mating effort

6. Methods • Five 1 minute clips of men talking to interviewer • Divided up into 10 second clips (30 clips total) • 30 points on the face analyzed for movement • Transferred to Androgynous animation face • Calculate mean distance travelled from center points

7. Methods (cont.) • Thirty 10 second clips • Analyzed for masculinity • Flirtatiousness ratings (1-7) • Short Term attractiveness ratings (1-7)

8. Methods (cont.) • Probability of Conception calculated • Flirtatiousness mostly agreed upon • Divide clips into most flirtatious and most masculine • Give each woman a score based on preference for flirtatiousness and one for masculinity • Run Hierarchical linear modeling

9. Results- Conception Probabilities • Estimated mean probability of pregnancy of following a single act of unprotected intercourse • Of all participants was 2.7% • Late follicular phase (days 7-15) was 4.8% • Menses and luteal phase (days 1-6 and 16-29) was 1.3%

10. Results

11. Results

12. Results

13. Weaknesses • Use of forward counting method instead of reverse counting • 5 young Christian men talking about Christmas for male facial data • Only identified male faces correctly 60% of the time

14. Possible Evolutionary Benefits • Direct • Increased probability of reward for mating efforts • Indirect • Good genes • Handicap Principle

15. Discussion • Not just movement, must be seen as flirtatious • Concealed ovulation • No testosterone-facial movement link found • Flirtatiousness and masculinity negatively correlated • Can we really determine gender based on facial animations?

16. Recommend research • Improvements in animation • What is flirtatiousness/masculinity? • How do static and dynamic masculinity differ?