One example of a great study done in the past, and would probably not get approved today, was of great value in terms of increasing our understanding in the field, which was the Stanford Prison Experiment.Read the original manuscript, and then discuss how the field of social psychology has changed over the past 40 years in terms of ethics in research. http://www.zimbardo.com/downloads/1973%20A%20Study%20of%20Prisoners%20and%20Guards,%20Naval%20Research%20Reviews.pdf
