Piliavin et.al.

Aim: To investigate a situational explanation of bystander behaviour.  How features of an emergency affects helping behaviour (race of Victim, State of victim, number of bystanders)

Participants:4450 Male and females travelling NY subway between 11 - 3 over 2 months

Method: field experiment 7.5 minute journey on train, 103 trials carried out, four teams of four people (2 observers, model, and victim)

Independent Variable: Black, White, Drunk, Ill

Dependent Variable (recorded by observers): time taken for first passenger to help, the gender, race and location of every helper

Controls: standardised victim always collapsed in the same way. The victim wore same clothes, observers recorded unobtrusively

Results:

• 90% participants were male
• The more passengers in the carriage the more people helped and faster

Conclusions:

• Found opposite to previous research: the more passengers in the carraige the more people helped so no diffusion of responsibility 
• Suggest Arousal Cost Reward model to explain why people help
• Heuristic device that propses that emergency situations create arousal and this is increased with identifiaction, empathy, proximity with the victim 
• This arousal is reduced by helping or leaving the scene or rejecting the victim as underserving of help