At a seminar, the economist Binmore noted this as a problem - every psychological study from Milgram on has been a trick, and so subjects (undergraduates) are a

At a seminar, the economist Binmore noted this as a problem - every psychological study from Milgram on has been a trick, and so subjects (undergraduates) are alert to this. He just wanted to study how markets / prices could form, if memory serves, but he could see students reading the instructions and trying to figure out where the trick was.