Answer:
Group polarization.
Step-by-step explanation:
Group polarization is when inside a group what first was an inclination to some ideas, after the individuals talk, those same ideas become much more stronger and radical. As the exercise exemplifies, the jury is deliberating and their initial attitudes are leaning neutral to slighty toward a guilty verdict. After a few days of deliberation, their ideas have strengthened considerably toward a guilty verdict. That's a good example of group polarization.