women’s probability of conception is associated with their preference for flirtatious but not...
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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
Introduction• Depending on the stage of a
women’s menstrual cycle, preferences in women’s behaviors changeo Height (Pawlowski & Jasienska, 2005)o Voice pitch (Feinberg et al., 2006)o Odor (Gangstad & Thornhill, 1998)o Facial symmetry• During the fertile window, women prefer
more masculine faces (Johnston et al., 2001)
Introduction• Traits related to testosterone thought to signal
immunocompetence (Folstad & Karter, 1992) and developmental healtho Height, voice pitch, facial structure
• Good genes may indicate a good quality mate, it could also indicate negative personality attributes (Perrett et al., 1998)o Coldness, dishonesty, less parental investmento High quality but high risk mateo Ovulatory shifts in preference leads to trading
off traits depending on chance of conception
Introduction• Flirting can also signal reward for
invested mating effort (Mishra, Clark, & Daly, 2007)o Signals interest to a women, who can be time-strained by fertility windowso 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)
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 highesto Signals reward for mating effort
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
Methods (cont.)
• Thirty 10 second clips
• Analyzed for masculinity
• Flirtatiousness ratings (1-7)
• Short Term attractiveness ratings (1-7)
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
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%
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
Possible Evolutionary Benefits
• Directo Increased probability of reward for mating
efforts
• Indirecto Good genes o Handicap Principle
Discussion• Not just movement,
must be seen as flirtatious
• Concealed ovulation• No testosterone-facialmovement link found• Flirtatiousness and
masculinity negatively correlated
• Can we really determine gender based on facial animations?