The participants were 186 people at Dartmouth who were paid. I'd wager >50% freshmen studying psychology. That's how a great deal of this sort of science works

The participants were 186 people at Dartmouth who were paid. I'd wager >50% freshmen studying psychology. That's how a great deal of this sort of science works - when I was a freshman psych major at Stanford we got extra credit in some entry level classes for participating.