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 change
o
o
o
o
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)
Introduction
• Traits related to testosterone thought to signal
immunocompetence (Folstad & Karter, 1992) and
developmental health
o 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 investment
o High quality but high risk mate
o 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 windows
o 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 highest
o 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%
Results
Results
Results
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
• Direct
o Increased probability of reward for mating efforts
• Indirect
o Good genes
o Handicap Principle
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?
Recommend research
• Improvements in animation
• What is flirtatiousness/masculinity?
• How do static and dynamic
masculinity differ?