Final answer:
The correct statement about informational influence is that it is used in situations where the appropriate course of action is unclear. Informational influence is distinct from normative social influence, which was the main factor in the Asch conformity studies.
Step-by-step explanation:
The most correct statement about informational influence is that it guides individuals when the appropriate course of action is unclear, which corresponds to the fourth option given. Informational social influence occurs when people conform to what they believe to be the expert opinion or actions of a group, particularly in uncertain or ambiguous situations. One example might be when someone reacts to a potential emergency in a movie theater by observing the actions of others. If others appear to evacuate the theater due to smoke (which could be from a fire or a special effect), a person who is unsure about the situation will likely follow the crowd.
In the well-known Asch conformity studies, the informational social influence was not the primary motivating factor for participants' conformity because the task was unambiguous. Instead, participants conformed due to normative social influence, which is more about adhering to social norms and avoiding ridicule.