The big problem with psychology, specially earlier, is that sometimes it seems just a species of "religion of manipulation" based in non scientific methods and not reproductible studies that did not probe anything (or even can be contradictory).
It was a big success because the "Lets flip this coin and let god decide if you go to jail or not" was still a huge 50% of 'free', so is changed by "If you please us and do something that we expect you to do, you could be free". There are not clear rules to play now, so you can bassically manipulate the percentage that pass the game at will.