波波玩偶实验

在该实验中，班杜拉选用儿童作为实验对象，因为通常儿童很少有社会条件反射。班杜拉试图使儿童分别受到成人榜样的攻击性行为与非攻击性行为的影响。然后将这些儿童置于没有成人榜样的新环境中，以观察他们是否模仿了成人榜样的攻击性行为与非攻击性行为。

班杜拉为这个实验制定了4个假设：

目击攻击性成人榜样行为的被试，将试图模仿或实施类似的攻击性行为，即使榜样不在现场。此外，他相信这些孩子的行为将会与那些目击非攻击性成人榜样行为的被试以及没有观察任何榜样的孩子（控制组）大为不同。

榜样不在现场时，观察非攻击性成人榜样行为的被试所表现出来的攻击性行为，将不仅少于目击攻击性成人榜样行为的被试，而且少于没有观察任何榜样的孩子。

儿童将更乐于模仿同性榜样的行为，因为儿童通常更为认同同性的成人与家长。

由于攻击性行为更多地具有男性化的特征，男孩们将会更乐于展示攻击性行为，尤其是观察富于攻击性的男性榜样的男孩。

在该实验中，班杜拉让斯坦福大学幼儿园年龄介于3-6岁之间的36名男孩和36名女孩观看一位榜样殴打一个波波玩偶。控制组、第一实验组和第二实验组各包括24名儿童，分别观看攻击性行为，以及观看非攻击性行为。第一实验组和第二实验组再按性别再次分组。然后再分别观看同性榜样和异性榜样。

The Bobo doll experiment was used by psychologist Albert Bandura to test his social learning theory. Between 1961 and 1963, he studied children's behaviour after watching an adult model act aggressively towards a Bobo doll. The most notable variation of the experiment measured the children's behavior after seeing the adult model rewarded, punished, or experience no consequence for physically abusing the Bobo doll.

Social learning theory proposes that people learn largely through observation, imitation, and modelling. The Bobo doll experiment demonstrates that people learn not only by being rewarded or punished but they can also learn from watching someone else being rewarded or punished. These studies have practical implications, such as providing evidence of how children can be influenced by witnessing violent behavior.

Experiment of 1961

Method

The participants in these experiments consisted of 72 children from the Stanford University nursery school between the ages of 37 months and 69 months. For the experiments, a third of the children were exposed to an aggressive model. Another third were exposed to a non-aggressive model. The rest of the participants formed the control group.

For the experiment, each child was exposed to the scenario individually to avoid being influenced or distracted by classmates. The first part of the experiment involved bringing a child and an adult model into a playroom. In the playroom, the child was seated in one corner filled with appealing activities such as stickers and stamps.

Experiment of 1963: live vs. filmed models

Introduction

For his 1963 study, Albert Bandura wanted to vary his original 1961 study by seeing if there were any differences in imitated aggressive behaviour after witnessing a filmed or cartoon model compared to a live model. He also wished to see if children watching aggressive behaviour from a filmed or cartoon model would experience a cathartic effect, or in other words, if they would experience a release of aggressive emotions from seeing a model carrying out aggressive behaviours.

Method

For the experiment, 96 children, 48 girls, and 48 boys, from the Stanford University nursery were divided into three groups. The first group watched a live model become aggressive towards a Bobo doll.

Experiment of 1965: reinforcement and punishment

Introduction

For his 1965 study, Albert Bandura wanted to see if children's learned behaviour would be influenced by vicarious reinforcement, or the act of imitating a behaviour observed in another person after witnessing that person be reinforced for said behaviour.

Method

In the experiment, 66 children, 33 boys and 33 girls were divided into one of three groups. The first group would witness a model display aggressive behaviours toward a Bobo doll, followed by a researcher praising the model for his behaviour and rewarding him with candy. The second group would witness the same scripted scenario of aggressive behaviours, but the model was instead reprimanded for his actions and hit with a rolled wooden golf club.

Social learning theory

The findings of these experiments support the principles of social learning theory proposed by Bandura. His research found that behavior is influenced by observing the behavior of others and imitating it. Central to this theory is the idea that the inclination to imitate behavior increases with the presence of an admirable model. Models are a crucial component to the learning of new behaviors and achieving change across different institutions, they drive individuals to shape their own behavior after the actions of models.

Criticism of the experiments

Laboratory studies of imitation often have low ecological validity, meaning key contextual features are absent; in a Bobo doll experiment, the child and the model do not have a prior relationship and do not interact with each other, even in the in-person environment. However, studies have found its approach to be well applied to aggression in institutions and the workplace, which implies that the larger study may have external validity and illustrates its relevance to real-world aggression.

When the Bobo doll experiment was repeated in 1990, findings showed that children who had not previously been exposed to a Bobo doll were up to five times more likely to imitate aggressive behavior compared to children who had been.