Peer pressure, yes, but also gullibility.

I was on a jury for a DWI case. Our initial vote was a 50/50 split. Evidence leaned toward a guilty verdict, but b/c the defendant refused a breath-test, not conclusive. Other tests were administered (like follow-the-finger and walk-a-straight-line), and their techniques were explained.

One juror, a teacher named Terry, was very loquacious and also convincing. He seemed to get stuck on a technical aspect of one of the tests, but also seemed to be overly enthusiastic about this. He said, "I just don't think the prosecutor proved his case." By the end of the 1st day, he had (singularly) convinced all but one of us to vote 'Not-Guilty'.

I'm nowhere near as vocal as Terry, but to me, the evidence we had indicated 'Guilty', and Terry's logic wasn't making sense. I'm not eloquent enough to have changed others' minds, but I wasn't buying Terry's arguments, either, and he knew this. We adjourned for the day.

When we resumed the next morning, Terry started off by saying, "I was thinking about it overnight, and I think the prosecutor proved his case, after all." Within just a few minutes, we had a unanimous 'Guilty' verdict.