This 23-minute TED Talk by Philip Zimbardo focuses on the Lucifer Effect and how good people can turn bad. Zimbardo is famously known for his Stanford Prison Experiment where he even got lost in the role playing. This talk would be great to use during your Social Psychology Unit.
WARNING- The video gives a warning at the beginning about the violent nature and some nudity in the video. The images are from the Abu Ghraib Iraq Prison Abuses 2008 Military Police Guards' Photos. It is from 5:03-6:47 and it even gives another warning before that part. I did not include any questions from that segment in case you would like to fast forward through it and I encourage that you watch it beforehand.
There are 18 questions for this video and I have included an answer key for your convenience.