Scientists have revealed a simple way to tell if someone fancies you: look at their pupils. According to anatomy experts Amanda Meyer and Monika Zimanyi from James Cook University, pupils tend to enlarge when a person is sexually aroused.
The pupil is the black hole at the centre of the eye, which expands and contracts to regulate light. The experts explained that the muscle around the pupil acts like a sphincter, controlled by the parasympathetic nervous system, while another muscle on the outside, stimulated by the sympathetic nervous system, enlarges the pupil. Pupils typically dilate in response to six triggers: fight, flee, feed, fornicate, get a fix, or focus.
However, responses vary by gender. A 2021 study cited by the researchers found that men's pupils dilate strictly according to their sexual preferences, while women's pupils dilate more variably. For example, heterosexual men's pupils enlarge in response to erotic images of women, while homosexual men respond to images of men. Lesbian women's pupils dilated more to erotic images of men, and heterosexual women's pupils dilated for both men and women.
The experts noted that pupil dilation synchrony between people may be more significant. 'Pupil mimicry' or 'pupil contagion' has been linked to mutual attraction and better teamwork, reflecting shared arousal states. However, they caution that context is crucial, as pupil dilation can also occur due to anticipation of rewards, emotional conflict, or processing emotionally charged stimuli such as scary movies.
