Piliavin et al. (1969) investigated bystander intervention using a field experiment.
Explain the term 'field experiment' by applying it directly to the setting and the manipulation of variables in this study.
105 exam-style questions on OCR A Level Psychology Responses to people in need, covering Piliavin et al. (1969): Subway Samaritan and Levine et al. (2001): Cross-cultural altruism. Each one has a worked solution and a mark scheme showing where the marks go.