Is juror 3 able to withstand the pressure of being alone in his decision? How does he handle being alone differently than juror 8 does?

Juror 8 had a tough skin and was unwilling to back down from his beliefs.

Juror 3 continued to condemn the boy up until the end, but he didn't hold out because of his own convictions, he held out because of his own relationship with his son. He projected his own problems and personal feeling onto the case. Once he realizes what is happening he relents.