Some of the most influential social psychology theories include cognitive dissonance, social identity theory and attribution theory. The shock experiment and the Stanford prison experiment are also highly influential social psychology theories.
In the 1950s, Leon Festinger brought the theory of cognitive dissonance into the public eye. Cognitive dissonance is the uncomfortable feeling of inconsistency that humans experience when they hold beliefs that contradict each other. People respond to this by either changing one belief or by selectively considering information that supports one belief but not the other. Other influential social psychology theories include drive theory, social learning theory and motivation crowding theory.