Both men and women were more likely to rate men as creepy, probably due to elements of physical and sexual danger. He also found that we are most likely to label people creepy when we don’t understand their behavior, or if it lies outside of social conventions. People who stand too close during a conversation, lick their lips often or laugh unpredictably creep people out.

Uncommon physical characteristics contributed to perceptions of creepiness as well. People with peculiar smiles, greasy hair, long fingers and pale skin were more likely to be rated as creepy in the survey. In general, people are creeped out by things that they don’t understand, or that don’t align with their conception of “normal behavior.” This is understandable from an evolutionary standpoint, because it’s better to be safe than sorry. Our instinctive response to unnatural situations, is to feel uneasy, as we may not know how to deal with whatever might happen next.

Certain professions and hobbies were also more likely to push our creepy buttons. Clowns rated the highest in terms of uneasiness, with funeral directors, taxidermists and sex shop owners rounding out the top four. Hobbies related to observing or photography were also mentioned by participants as being creepy. Can we be certain they aren’t photographing us?