Due to being carried out in a lab setting, and using an artificial doll as the figure to which the aggressive behaviour is directed towards, the study could be criticised for lacking ecological validity. The children's behaviour might be changed somewhat by being in the artificial environment, and so the findings cannot be easily generalised to wider settings. Furthermore, by the aggression being directed at a doll, rather than a human being, there is no significant consequence to the aggressive acts being observed and displayed, which there would be if reproduced in a real-life setting. The study itself supports the idea that motivation and expectancy of reward influences the likelihood of aggressive behaviour being exhibited, and so when there is greater risk of negative consequences e.g. hurting someone, when the aggressive behaviour is imitated in the real world the behaviour seen in the study may be diluted or the patterns may not exist at all. Therefore, psychologists must take this into consideration when drawing conclusions about human aggression from this study, as human aggression does not occur in an artificial, controlled environment, and so the validity and reliability of the behaviours in the study representing those which occur in the natural environment may be poor