When startled, I blink. So does everyone else. This blink response is hard-wired in our body. We cannot consciously alter it.

Researchers into the eye blink response startle their subjects with a loud noise, then rate the response on the prepulse inhibition (PPI) scale. These hard-wired responses give us a view into the limbic system or “the emotional brain” that helps control emotion, behavior, long-term memory, and smell. The limbic system is also highly interconnected with the brain’s pleasure center meaning it plays an important part in sexual arousal and the high of some recreational drugs. The limbic system also processes memory, tagging certain experiences as having special significance.

Lesbians have a strong blink response, closer to the response of straight men. Gay men’s responses are weaker than straight men’s, but not so dramatically.

One of the study’s author explained why this is important:

The startle response is pre-conscious and cannot be learned. It is mediated by an ancient region of the brain called the limbic system which also controls sexual behavior. This is very strong evidence that female sexual orientation at least may be ‘hard-wired’ in this region.


  • Lesbians: Strong blink response resembling straight men’s indicates prenatal hard-wiring of the limbic system.
  • Gay Men: Weaker blink response than straight men, but the differentiation is minor.


  • Qazi Rahman, PhD, et al., Behavioral Neuroscience, Oct. 2003

This article is part of a series, Written on the Body, exploring the correlations between our body structures and sexual attraction.