A fertile ground for prejudice?

New research suggests that women’s taste in muscular male strangers is more negatively biased when they are fertile. So if you don’t pull at the nightclub, could you blame genetics, asks John Holden?

Looking for that special someone in a dark, smoky club is often based more on instinct than anything else. If there’s alcohol involved, instinct doesn’t even come into it. But a study carried out in Michigan State University for online journal Psychological Science, suggests that women’s prejudice against male strangers may vary across their menstrual cycle.

Two studies were conducted on two groups of women. In the first, 252 women – 224 of them white, 28 black - were asked to associate words denoting physicality with European American or African American faces. In the second study, the researchers asked a smaller group of women to wear red, blue and yellow t-shirts and to perform similar word associations, this time for men also wearing red, blue or yellow t-shirts. Their findings were startling: when at their most fertile women were more biased against men in a different group to their own, whether of a different race, as in the first experiment, or whether wearing a t-shirt in a different colour to their own, as in the second. The bias against out-group men only held when they were perceived as being physically formidable.

Why would such impulses exist? Well from a biological evolutionary perspective, scientists argue that it is a throwback to more primal times. The findings are consistent with evidence that sexual coercion was a particular problem for women throughout evolutionary history, one that was especially acute in the presence of ‘out-group’ men (think Viking invaders). Prejudice may thus mirror the functioning of evolved psychological defence mechanisms which are strongest when the stakes are at their highest – i.e. when women are most fertile.

The authors offer as a possible alternative explanation for the bias against physically powerful out-group men the idea that cultural representations of these men – particularly African Americans – paint them as coercive and threatening. Previous research has found that women tend to prefer men perceived as physically dominant when they are at their most fertile. That the preference for dominant men didn’t hold in this case suggests that when dominance is combined with a perceived threat of coercion fertile women are no longer attracted to it.

This is not the first research to demonstrate the importance of more ‘internal’ urges when examining the crucial scientific issue of ‘scoring’. In 2007 a study on men’s tipping habits in lap dancing bars suggested that male customers were more likely to shell out their cash to dancers who happened to be at or nearing the most fertile phase of their cycle at the time.

Scientists at the University of New Mexico compared the earnings of lap dancers who menstruated naturally with those taking a hormonal contraceptive pill. During non-fertile periods of the menstrual cycle, all dancers being examined earned similar tips. But when the group entering their naturally occurring fertile period went to work, they tended to earn substantially more money than their counterparts.

The research couldn’t deduce whether being at their most fertile made the women behave in a more sexually desirable way or that the men could biologically detect and consequently seek out a more fertile woman. Either way, there’s room to include a new excuse on the list for not scoring on a night out: “She didn’t like my genes.”