The Asch Conformity Experiment

In psychology, the Asch conformity experiments or the Asch paradigm were a series of studies directed by Solomon Asch studying if and how individuals yielded to or defied a majority group and the effect of such influences on beliefs and opinions.
Developed in the 1950s, the methodology remains in use by many researchers.
Wiki - https://en.wikipedia.org/wiki/Asch_conformity_experiments