Motivations

9 to NG: He  really admired that 8 stood alone, and he now wants to hear more.  People accused 5 of changing his vote during the secret ballot that 8 abstained from, but it was really 9.  He may have been slightly subconsciously influenced by 8 putting his hand on his shoulder when 10 sassed him.

5 to NG: Not only did he have some sympathy for the defendant who was from the slums as he was, but he believed that a witness couldn't possibly hear the words "I'm going to kill you" as an el train was roaring by, therefor causing him to doubt the old witnesses testimony.

11 to NG: He changed his vote at the same time as 5, so we can assume that the noise was also a motivating factor.  Additionally, he raised the point that it would be illogical for the defendant to return to the scene of the crime.

2 to NG: He actually timed the "retracing" of the old witness's steps, and found that it was 42 seconds, not 15 seconds that the witness testified took him to cover 55.5 feet.  Also, he himself yelled at a man once who made him mad, so he could believe that the words "I'm going to kill you" don't necessarily mean it.

6 to NG: He's a painter, so when the discussion turned to the layout of the apartment and hearing a train go by, (he painted in a house close to a train), he paid close attention.  Right after the retracing of the witness's steps, he believed the old witness may have assumed he heard the words "I'm going to kill you" but didn't really.  It helped that 3 had been such a jerk to 9, and he even just helped restrain 3 from lunging at 8.

7 to NG: He had been complaining about missing his game the entire time...and when he saw that they were deadlocked in a 6-6 tie, he changed his vote to NG.  11 gave him a very tough time about this, saying he was playing games with a man's life.  7 didn't have a very convincing reason.

Foreman to NG:  He reluctantly raised his hand to change with 7 and 12 after the 6-6 vote to bring it to 9-3...but why?  Immediately beforehand, 5 spoke about the knife angle being all wrong, so that could have been it.  However, before that he brought up the psychologist's testimony that the boy had homicidal tendencies, but 11 shot that down by saying many people...even people in the room may be judged to have the same tendencies, and that doesn't mean you'll act on them.  This was illustrated beautifully when 3 lunged at 8.  Also helpful to note: right after that argument, he had a little bonding moment with 8 at the window, talking about one of his games in coaching football.

12 to NG: This guy was never really sure about anything.  When the angle of the knife was discussed and 5 said no experienced knife fighter would stab overhand, he changed his mind...but just for a little while.

12 to Guilty:  This guy went back to guilty after 3 and 4 claimed that the only thing that mattered was the female eye-witness to the murder was the only thing that mattered and you could throw out all the other evidence.  This brought the vote back to 8-4.

10 to NG: He was one of the three last holdouts.  When he saw that the vote had turned to 9 to 3 in favor of NG, he exploded.  He was then promptly shunned and shut down after his rant of bigotry.  For the rest of the play he sulked and caved, going along with the NG vote, even though he believed otherwise.

4 to NG:  It took 9's observation that the female witness had glasses just like four to finally convince him that there was a reasonable doubt: nobody wears glasses to bed, and the woman's eyesight was now called into question.

12 to NG:  This guy really was bouncing back and forth like a tennis ball.  It was the glasses testimony that convinced him too...you'll notice in the movie that he has glasses as well.

3 to NG:  The only thing that made this juror finally capitulate was the fact that the rest of the juror's made him realize that his anger towards his own son was influencing his vote for guilty.  He broke down in tears...and the 8 vs. GROUP conflict was resolved in the climax!