Partner status plays an important role in determining the extent of interest a woman shows in the opposite sex, a study has revealed.
Indiana University neuroscientist Heather Rupp asked 59 men and 56 women rated 510 photos of opposite-sex faces for realism, masculinity/femininity, attractiveness, or affect.
The participants were instructed to give their "gut" reaction and to rate the pictures as quickly as possible.
The men and women ranged in age from 17 to 26, were heterosexual, from a variety of ethnic backgrounds and were not using hormonal contraception.
Twenty-one of the women reported that they had a current sexual partner, compared to 25 of the men.
Rupp observed that women both with and without sexual partners showed little difference in their subjective ratings of photos of men when considering such measures as masculinity and attractiveness.
However, the researchers revealed, the women who did not have sexual partners spent more time evaluating photos of men, demonstrating a greater interest in the photos.
Rupp further revealed that the study did not find any difference between men who had sexual partners and those who did not.
"That there were no detectable effects of sexual partner status on women's subjective ratings of male faces, but there were on response times, which emphasizes the subtlety of this effect and introduces the possibility that sexual partner status impacts women's cognitive processing of novel male faces but not necessarily their conscious subjective appraisal," the authors wrote in a research article.
They also noted that influence of partner status in women could reflect that women, on average, are relatively committed in their romantic relationships, "which possibly suppresses their attention to and appraisal of alternative partners."
Rupp, assistant scientist at The Kinsey Institute for Research in Sex, Gender and Reproduction, added: "These findings may reflect sex differences in reproductive strategies that may act early in the cognitive processing of potential partners and contribute to sex differences in sexual attraction and behaviour."
The study has been published in the journal Human Nature.