In the play 12 Angry Men, to what extent are the jurors involved in the seriousness of the case and jury duty?

I think they begin the deliberations rather apathetic and wanting to go home. As the deliberations continue, things get more heated and Jurors begin to defend varying positions. The positions are based a mix of conjecture, personal/racial bias, facts of the case, and fatigue. Still, by the end of the play, the men seem to be invested in the case.