Who is the last juror to change his vote? What in his background might explain his stubbornness to do this?

The 3rd Juror is the last to change his vote. In this act, we see that the 3rd Juror, who has, despite his temper, been a somewhat coherent voice in the deliberations, is completely driven by his own demons to convict the boy, in place of his own son, with whom he has a troubled relationship. We see the layers of his decision making process peel away in his final monologue. It begins with him chronicling logically the case; however, it quickly becomes clear that he is no longer talking about the defendant. He says, “I can feel the knife goin’ in,” and we see that his personal connection and confusion about the case runs deep. Finally, the demon is named when 8th Juror says, “It’s not your boy. It’s somebody else.” 3rd Juror finally gives in to reason.