Bandura used 36 boys and girls in his experiment. He put 24 each in an experimental group and left 12 of each in a control group.
The 24 girls were shown a woman, who they identified with, playing nicely with the Bobo doll.
The 24 boys were shown a man, who they identified with, beating up the doll and swearing.
The children were then taken into another room without an adult, left to play with the toy in the room. The girl who had seen the woman playing nicely with the doll also played nicely. The observer watched through a window to remove demand characteristic.
The boy who had watched the man be aggressive and swear to the Bobo doll repeated the behaviour.
The children in the control group played nicely with the other toys an ignored the Bobo doll. This showed Bandura that children learn and imitate adults (older people).