Milgram's internal validity
☹️Orne & Holland- demand characteristics, p's knew it was set up. questioned why experimenter wasn't giving shocks & didn't respond to screams.
Milgram's response- p's filmed reactions, suggest it was real to them & showed real distress.
☹️Perry- followed up p's of Milgram's exp, 50% expressed doubt over legitimacy of shocks. Suggests situation was affecting obedience levels.
Defence- If they believed it was fake P's would go to 450v across all variations- this didn't happen suggesting they thought it was real.