Albert Bandura's 1961 Bobo doll experiment is one of the most famous in psychology's history. Now you can see video of the experiment with narration provided by Bandura.
In this experiment, Bandura demonstrated that children learn and imitate behaviors they have observed in other people. The children in Bandura's studies observed an adult acting violently toward a Bobo doll. When the children were later allowed to play in a room with the Bobo doll, they began to imitate the aggressive actions they had previously observed. Originally published in the Journal of Abnormal and Social Psychology, the study served as important experiment on Bandura's social learning theory.