Friday, October 26, 2012

Fertility drives female desire for attractive males

The bond between men and women is instituted by our biology resulting from billions of years of evolution. Male-female bonding is necessary for sexual reproduction, now the golden standard for successful life (although the a-sexual bacteria are not doing bad either). Because being attracted to the (mostly) other sex is a built-in mechanism directed by our most primitive brain structures, there is a lot of unconscious behaviour going on, which is excellent for scientists wishing to uncover our more primal, animal instincts. In this light, a recent study showed that how close a woman feels to her mate is dependent on how sexually attractive the male person is, and whether the female is in her fertile period.

Scientists from the University of California in Los Angeles enrolled undergraduate women in their study and asked them several questions regarding their feelings towards their mate. All women were in long-term heterosexual relationships, and the questionnaire was designed to uncover the perceived attractiveness of their male partners and how close they felt to their men. A total of 41 females were enrolled in the study, and the questionnaire was performed during two separate time periods: just before ovulation, which is the most fertile period of a female, and during the most infertile period. Answers to the questions were consequently compared.

A part of the questionnaire was devoted to assessing the commitment of staying in a long-term relationship. The scientists found that the time of the month (fertile vs. infertile) did not make a difference to the perceived feelings of commitment of the women towards their mate, nor did the degree of attractiveness matter. That means that although looks may be important, the females did stand by their choice of mate regardless of attractiveness.

While commitment remained unperturbed, the degree of closeness was found to be different between the two time points. Women in their fertile period were found to be less close to their mate when he is perceived as unattractive, while an attractive man resulted in increased feelings of closeness during the fertile period. The scientists found that females coupled to more unattractive males were more likely to find things at fault with their men. In a follow-up study with a group of 67 females, the researchers repeated the experiments, and tried to assess which factors drive the changes in degree of closeness. They found that women in a relationship with an unattractive male were more likely to find something to be at fault in the behaviour of their mate during their fertile periods.

Evolutionary conflicts
Several hypotheses can be generated from the conclusions of this study, to provide an explanation for the results. According to the scientists, the changes in closeness perception might stem from an internal conflict in the more primitive sections of the brain, that are involved with 'choosing' a mating strategy. It is commonly known from evolutionary theory that women try to choose the best males suited for them to spread their genes by means of reproduction. Good looks are used as a proxy for good genes, and although this may not necessarily be a good surrogate, it could very well be that fertility results in a stronger (primitive and unconscious) desire to find a suitable male: evolution could have driven this behaviour. However, this feeling is apparently not strong enough to change the way women think about the long-term potential of their relationship. It would be interesting to see whether this is actually true, by conducting a similar study with a long follow-up time to assess relationship 'outcomes'.

Other studies
This is not the only study in this interesting field of research. Other groups of scientists have also found an influence of the reproductive cycle on the behaviour and perceptions of females. An example is a study showing that fertile periods make women dance more attractively. Another piece of research showed that females have a different choice in men during their periods of fertility, which ties itself nicely to the present study. While several evolutionary theories are available surrounding these behavioural changes, the mechanisms by which our biology governs it are known. The 'love hormone' oxytocin likely plays a large role, as shown before, but we can also find clues in our DNA.
Two of the researchers that conducted the study. It is unknown how they rate their own mates.

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