The resident assistant of a campus residence hall notices that when a team of five students is assigned to clean the common room, the room is not as well cleaned as when only one student is assigned to clean it. What phenomenon does this example illustrate?

Social loafing

Explanation:

Social loafing -

It is the case, when the people are in a group, and the tendency of a particular person to put on less effort, being part of the group, is known as Social loafing.

As, in a group all the members are supposed to put efforts to accomplish a particular task or goal.

Hence,

from the question, the phenomenon of Social loafing is shown in the question.