Evaluation of Procedure/Method:
Strength: A main strength of the study has to be its high level of ecological validity. The study was done in a true to life environment and consisted of an incident, which could and does happen. However, some of the participants were very close to the victim and were in a situation where they could not escape. This is often unlike many other situations where we come across emergency situations and this may be one of the reasons why diffusion of responsibility did not occur. The sample size was also very large and we would assume a fairly representative sample of New Yorkers. The researchers should therefore be able to generalise their findings with much more certainty than if they had carried out a study on say 40 students. Weaknesses: The study can be criticised on ethical grounds. A problem with the field experiment is that the participants cannot give their consent, because they do not know that they are participants in an experiment. Similarly the participants are being deceived because they are unaware that it is not a genuine emergency. Participants were also not debriefed as this would have been almost impossible. Following from this it is possible that participants had feelings of guilt, distress, and anxiety. A further problem with field experiments is that they are more difficult to control than laboratory experiments. For example we could question whether travellers on the trains saw more than one trial. Field experiments are also more difficult to replicate and more time consuming and expensive.