Source: William Brady & Jay Van Bavel—New York University

It is obvious that we are influenced by those around us, but in the early to mid 1900's, psychologists began to study how potent social influence can be on our thoughts and behaviors. Motivated in part by attempts to explain the behaviors of Nazi soldiers in World War II, one topic of considerable interest at the time in psychology was conformity, the phenomenon in which people match their attitudes, behaviors, or beliefs to group norms.

While behaviorist psychology explained conformity in terms of simple reinforcement learning (e.g., it is rewarding to follow the group), Gestalt psychologists argued that conformity is the result of perception being determined just as much by our social world as the physical world. Starting in 1951, Solomon Asch conducted a series of experiments to test the Gestalt idea that group norms can influence our perception of the world, even when the group norm is incorrect in a judgment of something that can be measured objectively. The experiments involved participants making a judgment about which of three comparison lines matched the length of a standard line. The experiments consisted of a group of people who were confederates with the exception of the one participant, and on certain judgments the confederates purposely claimed that the wrong comparison line matched the standard. This allowed the experimenter to measure whether the participant would conform to the objectively incorrect majority judgment. Solomon's experiments not only demonstrated the power of group norms on behavior, but it also laid the groundwork for decades of social psychological research studying social influence.

Inspired by Asch, this video demonstrates how to design a task to test the power of conformity on judgments.¹