Beware of people wearing dark glasses!

Dark glasses can make someone look mysterious or shady, with good reason...  

It turns out a lot of us actually change our behavior when wearing shades or while in a darker environment. Participants in a study were asked to divvy up money between themselves and a stranger. Those wearing dark glasses took more for themselves. 

In another experiment, people were asked to complete some math problems and then score themselves. Those in a dimly lit room gave themselves a curve and higher grades than they deserved.