It lacked INTERNAL VALIDITY. The participants could not have belived the shocks were real. However Milgram states that from the results of the questionnaire, most participants believed in the setup.
It lacked EXTERNAL VALIDITY. This situation was unlikely to occur in everyday life therefore the participants acted in a different way to how they would usually act and the results could not be generalised to the real world. Though Milgram states that the participants clearly believed the situation was real (shown in video footage of the experiment) so the experiment had MUNDANE REALISM.
The participants could have been affected by OTHER FACTORS such as the prestigous environment.
There is vast CROSS-CULTURAL SUPPORT from further similar studies.
Other Points: Variations of this study has been carried out to investigate the effects of:
Environment,
Proximity to the victim,
Authoritive figures,
Social support and
Other factors have on the extent of obedience.
社会心理学家认为个体之所以会有服从行为，主要的原因是两个。
一、合法权力。我们通常认为，在一定情境下，社会赋予了某些社会角色更大的权力，而自己有服从他们的义务。比如学生应该服从教师，病人应该服从医生等，在实验室中，被试就应该服从主试，特别是陌生的情境更加强了被试服从主试命令的准备状态。
二、责任转移。一般情况下，我们对于自己的行为都有自己的责任意识，如果我们认为造成某种行为的责任不在自己，特别是当有指挥官主动承担责任时，我们就会认为该行为的主导者不在自己，而在指挥官。因此，我们就不需要对此行为负责，于是发生了责任转移，使得人们不考虑自己的行为后果。
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