It is critical to remember that the jury is composed of 12 white men and that the defendant is a member of a minority. As a result, the groupthink is revealed in alarmingly prejudiced ways, with one of the jurors dismissing the defendant as a "slum kid," a sentiment that appears to be shared by many of the other jurors. It becomes clear that one of the reasons that they are willing to believe in the defendant's guilt is that he is different from them. This is an example of devindividuation. First, rather than acting as individuals, the eleven jurors are acting as a group. This causes them to lose some of their social constraints and act in ways that are considered deviant. Although racism was more acceptable during that time period, there was still some social taboo against suggesting that the defendant was guilty simply because he was Hispanic and poor. Furthermore, the fact that so many of the jury members are willing to think that he is guilty because of his group membership rather than his individual characteristics It is also important to understand the impact of the time deadline on the jurors. Juries do not have unlimited time in which to make a decision. However, much of the time constraint is imposed by the jurors, themselves, because they want to make a decision so that they can get be finished with jury duty and be able to move on with their lives. This creates a type of false pressure. Connie Gersick helped explain how time deadlines impacted the group process by the development of a punctuated equilibrium model that suggests that "groups go through periods...

One can see this displayed several times throughout the movie, most notably when the jurors ask about the time and find that is already after 6 p.m.
An interesting example of the collective effort model is when Mouse begins to speak about the angle of the stab wounds. He does not believe that the boy could have made the stab wounds. However, when it appeared that the rest of the jurors were convinced of the defendant's guilt, he did not speak up about his feelings (Lumet, 1957). Knowing that he is not the only person questioning the boy's guilt makes Mouse realize that discussion of the wounds is not futile. When he believes that his "individual efforts will be important, relevant, and meaningful for achieving outcomes" that he values, he begins to provide more input (Kassin et al., 2010). Eventually, this type of collective effort begins to transform ideas, as more and more jurors come forward with question and concerns that they had about the defendant's guilt. This leads to a change in the consensus in the room, though the audience is left to wonder whether the jury's newfound conviction that the defendant is not guilty is as subject to change as their original belief in the defendant's guilt.

References

Kassin, S., Fein, S., & Markus, H.R. (2010). Social psychology. Wadsworth/Cengage Learning.

Lumet, S. (1957). 12 Angry Men. New York: MGM Studios.