During the era of hunter and gatherers when individuals
traveled and lived in tribes consisting of bands of extended kin, they did not
have contact with many people outside of their group. Psychologists have found
that there is a higher level of trust with in-group members (people within your
tribe) compared to out-group individuals (people not in your tribe) (Gaertner
et al., 2006). People also tend to think more highly of in-group members than
their out-group counterparts (Gaertner et all., 2006). This calls into question
how we were able to perpetuate the human race as incest would be extremely
likely to occur and the negative association with out-group members.
I assisted with a research team that was interested in this
topic and the possible explanation for this phenomenon. The hypothesis was
women were more attracted to out-group men when ovulating (peak time for
fertilization). To test this, a questionnaire was given to Caucasian females from
Tennessee (where the study was conducted) that were not on birth control (normal
ovulation) that required them to rate their stereotypes of men with different
ethnicities regarding attractiveness, competency, intelligence etc. This was
able to gauge who the participants were attracted to in terms of race at that
time. They were also asked for the last date of their menstrual cycle to
determine if they were ovulating. They were then exposed to various pictures of
men of different races and had to rate their attractiveness and whether they
thought they would be from Tennessee (in-state) or another state.
The findings indicated that women are in fact more attracted
to out-group men while ovulating. This makes sense as ancestral females would
have a long-term partner within their tribe that they trusted to protect them
and raise children with since there is a stronger sense of trust with in-group
males (Brewer, 1997, Gaertner et al., 2006). But, in order to increase genetic
variation, females participated in infidelity and mated with out-group men when
they were more attracted to them during ovulation (Salvatore, 2012). This behavior
is also seen in chimpanzee populations that indicates this may be just an
evolutionary characteristic in primates (Itani & Zuzuki, 1967).
Citations:
Brewer, M. B. (1997) On the social origins of human nature.
In C. McGarty & S. A. Haslam (Eds.), The Message of Social Psychology
(pp.54-62). Oxford, UK: Blackwell.
Gaertner, L., Iuzzini, J., Witt, M. G., Guerrero, M., &
Oriña, M. M. (2006). Us without them: Evidence for an intragroup origin of
positive in-group regard. Journal of Personality and Social Psychology, 90, 3,
426-439.
Itani, J. & Zuzuki, A. (1967). The social unit of
chimpanzees. Primates, 8, 355-381.
Salvatore, Joseph Frederick.
"Strangers with benefits: Ovulation and attraction to outgroup men."
(2012).
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ReplyDeleteAs soon as I read the part about the in-group and out-group of tribes, I immediately thought of West Side Story and the Sharks vs. the Jets. I digress, however I always kind of wondered about this in tribal settings. Given that tribal settings were often smaller cohorts of individuals, the likelihood of passing on genetic similarities was high. In the study performed, were women researched only attracted to the outgroup men while ovulating, or during the entire cycle? I can see how a more genetically diverse individual may heighten one’s awareness during ovulation, but are these individuals not seen as worthy when not ovulating?
ReplyDeleteIn the era of prehistoric nomads, I can understand that trust within one’s tribe was taken seriously, and survival was key. I am wondering though when you use “infidelity,” if these tribes knew that during certain “cycles of the moon” that their women were copulating with the competition and vice versa. Biologically during ovulation something was initiated within these people to find variation outside of their tribes, I just wonder socially what that looked like and how it really played out beyond what was mentioned in the blog.
Last year, a 90,000-year-old bone was discovered in Siberia. This bone was genomically analyzed and was discovered to be the first evidence of Neanderthal and Denisovan mating, two distinctly different human groups (Warren, 2018). Though it was predicted the two groups mated to enhance genetic diversity, this was the first-generation hybrid proof of it occurring. Though it was rare for the two groups to mate given they usually lived in regions away from each other, in the area of Altai Mountains both groups were present, so the opportunities were there. Going back to your study, in today’s age, being attracted to someone “opposite” of you but only during ovulation seems understandable, but also odd that it would only be during that time frame and not always. Unless biologically at certain times of the cycle, women can be more “realistic and understanding” with the type of mate who can provide a stable and safe environment for her as opposed to what her hormones are telling her is desirable during ovulation.
Warren, M. 2018. First Ancient-human hybrid. Nature. 560, 417-418. https://www.nature.com/articles/d41586-018-06004-0