At least since "12 Angry men," the jury cliche has been the lone holdout for acquittal who stays stubborn and ultimately turns everyone else around. According to an IU study, there may be some truth to it:
Additionally, in about one in four juries, the deliberations were polarized enough that there were clear faction leaders, or noticeably vocal jurors, arguing for each side from the beginning of deliberations. Jury forepersons and pro-acquittal faction leaders appeared to have a disproportionate amount of influence over the juries as a whole. The foreperson's initial verdict stance and the presence of a pro-acquittal faction leader were both strong predictors of verdict, with convictions much more likely when the foreperson initially thought the defendant was guilty and less likely when a juror emerged as the leader of a group arguing for acquittal.
Stick any group of people together charged with a task but not given explicit directions, and a leader will emerge naturally. That's been my experience anyway, and, as often as not, it turns out to be me. I don't think it's because I want to lead -- I just want to get the stupid meeting over with. That's probably not a good attitude to take into the jury room. This study, by the way, isn't very flattering of Hoosier juries' deliberative processes:
The study found that Indiana juries reported understanding the judges' instructions and thoroughly reviewing the evidence. However, it also found that a fair number of juries did not perform optimally in that they took their first vote before much, if any, discussion of the evidence (20 percent of juries polled) and most juries did not extensively discuss the evidence before taking a first vote (69 percent of the juries polled). Further, less than half of the juries (41 percent) reported that opinions were systematically gathered from jurors on the major issues and only 26 percent of the juries reported systematically going around the table to gather member views before a first vote.