Which key researcher is known for conducting a lines experiment that explains normative social influence and informational social influence?

The researcher known for conducting the lines experiment that illustrates both normative social influence and informational social influence is Solomon Asch. His studies involved participants judging the length of lines in a group setting, where confederates deliberately provided incorrect answers to see if the true participant would conform to the group's responses. This experiment highlighted normative social influence, wherein individuals conform to fit in with the group, and informational social influence, where individuals conform because they want to be correct in their judgments.

Asch's work showcased the powerful effects of social pressure on individual behavior, providing key insights into group dynamics and conformity. Through his experiments, it became evident that people often conform to group opinions, even when they are aware that those opinions are incorrect, which deepens our understanding of social psychology.