Solomon Asch was a pioneer in Social Psychology. He designed and conducted a series of many experiments trying to understand individual judgment, including moral and ethical judgment, and the powers that, for better or worse, influence it.
The number of participants in the experiments varied, but often there were eight. One of them was always told they would be part of an experiment on visual judgment. This person believed the other seven people were told the same thing and were participating in the experiment on the same terms. What they didn’t know was that the other seven were all actors following a script.
It is stunning to realize that there was no instruction to conform given, suggested, or even implied. Not from the experimenter. Not from the other participants. The pressure and demand to conform came entirely and completely from the pressure the person put on themselves. They were their own executioner.
There are many, many situations in life in which each of us is the seventh person.