The most plausible explanation for the female response is evolutionary. Their body is not connected to their mind, which is very different from guys.' 'They respond to anything that is in some way sexual,' said Rieger.
Heterosexual women, however, responded to both sexes, confirming previous research that women have more fluidity in their sexuality. Predictably, heterosexual men showed more pupil dilation after being shown sexual videos of women, and little to men.