Bandura, A., Ross, D. & Ross, S.A. (1961). Transmission of aggression through imitation of aggressive models. Journal of Abnormal and Social Psychology, 63, 575-582.
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Albert Bandura and his colleagues demonstrated that children's behavior is influenced by observational (or imitative) learning. In the aggressive condition, girls and boys observed an adult act physically aggressive (e.g., strike with mallet) towards a Bobo doll. In the non-aggressive condition, girls and boys observed an adult interact with a Bobo doll in a non-aggressive manner. A short time after viewing the adult interact with a Bobo doll, the children in both conditions were observed during individual freeplay, and the results indicate that children in the aggressive condition were significantly more likely to act aggressively towards a Bobo doll than childen in the non-aggressive condition (as well as the control condition). There were also gender effects. Boys exhibited more physical aggression than girls, and children who observed a male adult in the aggressive condition exhibited more aggression than children who observed a female adult in the aggressive condition.
This article is considered a classic in psychology because it suggests that observational learning yields responses and behaviors that otherwise would not occur. At the time of its publication, the article filled a gap in the literature that focused on reward/punishment theories of learning.