Ibecome more cautious in the group because, when i discuss a personal decision with the group members, they all suggest many interesting, influential arguments favoring a cautious approach. my shift is consistent with the theory of group polarization.

I believe the answer is Informational influence of group polarization.
The informational influence describe group polarization as process of conformity that individuals initiated due to the pressure to be accepted by other member of social groups.
From the case above, we can see the pressure in the speaker's need to conform to what other members seemed as 'interesting'