One of the social psychological concepts is compliance. Compliance is conformity that involves publicly action in accord with social pressure while privately disagreeing. People comply to avoid punishment. While in the locked room a vote was taken to start things off. The votes were spoken out loud and counted. While going in order, 'guilty', 'guilty', 'guilty', then a hesitant 'guilty'. The juror that hesitated to say guilty, only agreed with the others so he could avoid social punishment, disliking. He only said guilty to comply with the rest of the group. What would happen to him if he disagreed? He had no choice but to agree, unless he wanted to face the rest of the jurors.
Another concept is the overconfidence phenomenon. This is the tendency to be more confident than correct. You can see this take place if you follow one man's path in this movie. He is confident the young man is guilty. Even when he is confronted with theories that the young and may have not committed the crime, he still believes he is correct. Every juror is convinced that he was not guilty, because of reason of doubt, except for one. No matter how much evidence was presented to this man he still is confident the young man committed the crime. The juror is overconfident he is right and overestimated the accuracy of his beliefs.
A third social psychological concept that occurred in this movie is stereotyping. When the jurors were in the locked room, some of them kept referring to the young male as 'one of