Milgram says participants did not know about hoax
In regards to the criticisms of whether or not participants knew about the study being a hoax Milgram responded stating a research team interviewed all participants and they found that fewer than 20 percent challenged the reality of the situation (the experiment) (Forsyth, 2010, p. 248). In response to many individuals questioning whether or not participants knew that the shocks were not real, Milgram said,
Many subjects showed signs of nervousness in the experimental situation, and especially upon administering the more powerful shocks. In a large number of cases the degree of tension reached extremes that are rarely seen in socio-psychological laboratory studies. Subjects were observed to sweat, tremble, stutter, bite their lips, groan, and dig their fingernails into their flesh (Milgram, 1974, p. 375).
In Thomas Blass, Ph.D.’s book The Man Who Shocked the World, a book about Milgram’s obedience experiments, Blass says “The distress of the participants was so great that the publication of the study sparked a controversy over the ethics of socio-psychological research” (Blass, 2004).