Pupils will also pop when we experience emotions on the sunnier end of the spectrum like love or happiness. It has been shown that men even translate that response into viewing larger pupils as more attractive or beautiful.
Italian women in the Middle Ages recognized the beauty endowed by wide-open pupils, they would dilate their own eyes with belladonna. Unfortunately, the plant secreted not only the chemical atropine, which draws back the irises, but also a toxin that would deteriorate these women's eyesight and possibly poison them. Since atropine has long been identified as a toxin, optometrists use a synthetic derivative to dilate patients before examining their eyes.