With his roommates, jason participates in a group discussion on the merits of gun control. once the discussion is over, jason finds that he and his roommates have all adopted similarly strong pro-gun control attitudes. this is an example of groupthink. group polarization. social loafing. social facilitation.

I believe the answer is: group polarization.

group polarization refers to a condition when an individual actions become much more extreme every time we are near group members with similar principle compared to when we're alone. People tend to do this in order to avoid being negatively perceived by other members of their group.