The 4th juror is a very fact-based, albeit conceited, man, and when presented with facts that put his evidence in question he accepts it. The biggest proof to his character is that unlike the rest of the jurors who adamantly believe the boy in guilty, he doesn’t get angry at those arguing with him. He believes himself to be right, and is merely entertaining the idea that he may be wrong, as far as he is concerned, the evidence points right at the boy.
The final and perhaps most biased juror we are introduced to, is juror number three. While he did not grow up with "them" in the slums, he had his own personal experience with kids and violence, as he accidentalty lets slip:
"It's the kids. The way they are—you know? They don't listen. (Bitter) I've got a kid. When he was eight years old, he ran away from a fight. I saw him. I was so ashamed, I told him right out, "I'm gonna make a man out of you or I'm gonna bust you up into little pieces trying." When he was fifteen he hit me in the face. He's big, you know. I haven't seen him in three years. Rotten kid! You work your heart out.... [Looks away