These eyes… Which picture do you like better?According to Eastman, there is a strong correlation between arousal and specific eye movements like dilation and blink rate. Our eyes naturally dilate to allow more light in, but dilation also occurs in response to cognitive and emotional events. So when we’re interested or in any way emotionally stimulated — positively or negatively — in what we’re looking at, our pupils dilate.

In fact, men tend to be attracted to women with larger pupils. So much so that in Italy, over five centuries ago, women used Belladonna plant extract to dilate their pupils in an effort to appear more attractive, Scientific American reported.