Bandura, A, Ross, D and Ross, S A (1961), Transmission of aggression through imitation of aggressive models. Journal of Abnormal and Social Psychology, 63(3): 575–82


This study examined social learning theory by Bandura et al. An experiment was conducted to determine whether a child would imitate aggressive behaviour if he or she witnessed such behaviour in an adult. Observation was used as a method of collecting data to compare several variables.

Psychology Being Investigated

Bandura, A, Ross, D and Ross, S A (1961), Transmission of aggression through imitation of aggressive models. Journal of Abnormal and Social Psychology, 63(3): 575–82

The psychological theory being investigated in this study is Social Learning Theory. This theory, primarily developed by Albert Bandura, suggests that people can learn new behaviors and acquire new information by observing others. Key components of Social Learning Theory include:

Observational Learning – This refers to the process of learning behaviors through observing and imitating others. In the context of this study, the focus is on how observing aggressive models influences the imitation of aggressive behaviours.

Role of Models in Learning – The theory emphasizes the significance of models (others who are observed) in the learning process. In this study, children observed adult models exhibiting either aggressive or nonaggressive behaviors, and their subsequent behavior was studied.

Imitation of Behaviours – The study examines how exposure to aggressive models leads to the imitation of similar aggressive behaviors in new settings, even in the absence of the original model. This demonstrates the theory’s assertion that learning can occur through observation alone, without reinforcement.

Impact of Aggressive Models – The study explores the hypothesis that children exposed to aggressive models will reproduce aggressive acts, demonstrating the social learning of aggression.

Gender Differences in Imitative Behaviour – The study also considers the influence of the model’s and subject’s gender on imitative behavior, reflecting Social Learning Theory’s perspective that learning is influenced by social and cognitive factors, including gender norms and roles.


The study is based on prior research exploring the phenomenon of identification and observational learning. Key elements of the background research include:

Identification and Incidental Learning – An earlier study by Bandura and Huston (1961) focused on identification in terms of incidental learning, demonstrating that children readily imitated behaviors exhibited by an adult model in the presence of the model. This concept formed a foundation for understanding how children learn and replicate observed behaviors, particularly aggressive actions.

Observational Learning and Social Influence – Research by Blake (1958), Grosser, Polansky & Lippitt (1951), Rosenblith (1959), and Schachter & Hall (1952) revealed that merely observing the responses of a model could facilitate subjects’ reactions in social settings. These findings highlight the significant impact of observation on behavior, especially in immediate social influence contexts.

This background research underscores the critical role of observational learning and the influence of models in shaping behavior, particularly in children. The studies collectively suggest that exposure to certain behaviors, including aggression, can lead to the imitation of these behaviors, paving the way for Bandura, Ross, and Ross’s exploration of the transmission of aggression through imitation​​.


  1. Imitation Influenced by the Sex of the Model – The study aimed to investigate how the sex of the model affects the imitation of behavior. Specifically, it examined whether boys would show more aggression than girls following exposure to a male model, especially in behaviors considered highly masculine-typed.
  2. Effect of Nonaggressive Models on Subjects – Another aim was to observe the impact of nonaggressive models on the subjects. The study hypothesized that subjects who observed nonaggressive models, particularly subdued male models, would exhibit less aggressive behavior than their controls.


The subjects were 72 children (36 boys and 36 girls) enrolled in the Stanford University Nursery School, aged between 37 to 69 months, with a mean age of 52 months​​​​.

Experimental Design

  • Division of Groups – Subjects were divided into eight experimental groups of six subjects each and a control group consisting of 24 subjects.
  • Exposure to Models – Half the experimental subjects were exposed to aggressive models, and the other half to nonaggressive models.
  • Model’s Role – Two adults, a male and a female, served in the roles of models.
  • Same-Sex vs. Opposite-Sex Models – The study hypothesized that subjects would imitate the behavior of a same-sex model to a greater degree than a model of the opposite sex, with boys more predisposed than girls toward imitating aggression, especially when exposed to the male aggressive model​​​​.

Research Methods

  • Observation of Model’s Behaviour: Children were individually exposed to either aggressive or nonaggressive adult models.
  • Measurement of Imitative Behaviour: Children’s behaviors were observed and recorded following exposure to these models to assess the extent of imitative aggression.

Research Technique for Data Collection

  • Data were collected through observational methods, where the children’s behaviors post-exposure to the models were monitored and recorded.

Measured and Manipulated Variables

  • Manipulated Variables: The presence of aggressive versus nonaggressive models and the sex of the models.
  • Measured Variables: The level of imitative aggression displayed by the children after exposure to the models.


Experimental Conditions

  • Children were brought individually to the experimental room.
  • The child was seated at a table with activities (potato prints and picture stickers) to occupy them.
  • The model was placed in the opposite corner of the room with a small table, chair, a tinker toy set, a mallet, and a 5-foot inflated Bobo doll.
  • In the nonaggressive condition, the model quietly played with the tinker toys, ignoring the Bobo doll. In the aggressive condition, after a minute, the model began displaying aggressive behaviors towards the Bobo doll​​.

Experimental Room and Materials

  • The room contained a mix of toys that could be used for imitative or nonimitative aggression and toys that were predominantly nonaggressive. Aggressive toys included a Bobo doll, a mallet, pegboard, dart guns, and a tether ball with a face. Nonaggressive toys included a tea set, crayons, coloring paper, a ball, dolls, bears, cars, trucks, and plastic farm animals​​.

Observation and Rating of Behaviour

  • Each child spent 20 minutes in the experimental room.
  • Their behavior was rated in terms of predetermined response categories by judges observing through a one-way mirror.
  • The session was divided into 5-second intervals, yielding a total of 240 response units for each subject​​.


Complete Imitation of Models’ Behaviour – Subjects exposed to aggressive models showed significantly more physical and verbal aggressive behaviour resembling that of the models, compared to the nonaggressive and control groups, who exhibited virtually no imitative aggression​​.

Physical and Verbal Imitative Aggression – The effect of treatment conditions was highly significant for both physical and verbal imitative aggression​​, with subjects exposed to aggressive models scoring significantly higher than those in the nonaggressive or control groups​​.

Nonaggressive Verbal Responses – Approximately one-third of subjects in the aggressive condition also repeated the model’s nonaggressive verbal responses, a behaviour not observed in the nonaggressive or control groups​​.

Partial Imitation and Nonimitative Aggression – There were significant differences in partial imitation, such as the use of a mallet aggressively towards objects other than the Bobo doll​​, and sitting on the Bobo doll​​. Nonimitative physical and verbal aggression was also significantly more prevalent in subjects exposed to aggressive models compared to nonaggressive ones​​.

Influence of Sex of Model and Subjects on Imitation – Boys showed more imitative physical aggression than girls in the aggressive condition. Male subjects exposed to male models exhibited more physical and verbal imitative aggression than female subjects. Nonaggressive and control subjects showed differences based on the sex of the model, with male models having a greater influence​​.

Nonaggressive Behaviour – Significant differences were observed in nonaggressive behaviours as well. Subjects in the nonaggressive condition engaged more in play with dolls and spent more time sitting quietly without engaging in play, compared to those in the aggressive condition​​.


The study conclusively demonstrated that children could acquire and imitate aggressive behaviors through the process of observational learning. The research provided strong evidence that exposure to aggressive models increased the likelihood of aggressive behaviors in children. These behaviors were not only imitations of the observed actions but also included generalizations of aggression to new settings and objects.

Furthermore, the study highlighted the role of the model’s characteristics, such as sex, in influencing the extent and form of aggression imitated by children, with boys more likely to imitate male models. This finding underscored the significance of social and environmental factors in shaping behavior, particularly in young children.

The research by Bandura and colleagues was groundbreaking in its time, laying the foundation for the development of social learning theory. It shifted the focus from purely individual or internal processes (like instincts or personal traits) to the role of external influences in behavioral development. This had profound implications for understanding social behaviors and for educational and parenting strategies, emphasising the importance of role models and the social environment in shaping children’s behaviour.


Experimental Design – The study used a well-structured experimental design, including control and experimental groups, to isolate the effects of observing aggression. This allowed for a clearer understanding of cause-and-effect relationships. The use of a control group who were not exposed to aggressive models provided a baseline for comparing the behaviors of children exposed to aggression, enhancing the validity of the findings.

Standardised Procedures – The researchers implemented standardized procedures across all participants, ensuring consistency in the treatment of each child. This included the use of the same aggressive or non-aggressive models and the same set of toys and instructions. Such standardisation reduces the risk of extraneous variables influencing the results, thereby increasing the reliability of the findings.

Quantitative Measures – The study employed quantitative measures to assess aggression levels, allowing for objective data analysis. The use of a pre-determined scoring system to measure the frequency and type of aggressive behaviors provided a clear, measurable outcome that could be statistically analysed, enhancing the study’s empirical rigour.


Lack of Ecological Validity – The study was conducted in a laboratory setting, which may not accurately reflect real-life situations. The artificial environment and the structured nature of the experiment could influence children’s behaviour in ways that wouldn’t necessarily occur in their natural environments. This limits the generalisability of the findings to real-world settings.

Ethical Concerns: – Exposing young children to aggressive behaviour and encouraging them to engage in aggression raises ethical issues. Such exposure could have unintended long-term effects on their behavior and psychological well-being. The study did not address the potential negative impacts of this exposure.

Short-Term Observation: – The study only observed children’s behaviour immediately following exposure to the model. This short-term approach does not provide information about the long-term effects of observing aggressive behaviour. It’s unclear if the imitated aggression would persist, diminish, or evolve.