The four most beautiful and tale-teling experiments that combine the best of experimental science and participant observation are:
They all paint a rather bleak picture of the most of the humanity, however. Apparently, when given the chance most earthlings will turn into monsters. It is only their own pain or the fear of authority - God, government, parents - that keep most of them from that.
Interestingly enough, all the three experiments are considered controversial. All had to be terminated by emergency, as they, nearly or very much so, went out of hand - quite like actual life outside the ivory silo always does.