You are walking across campus and see a large group of students gathered outside the student union listening to someone talk. you stop and try to listen, but you can't get close enough. you ask another member of the crowd what's happening, and you are told that someone was proselytizing and that some students gathered to listen while others argued. what does this tell you about crowds?

That in any crowd, people have different motivations.

This is shown by the two groups that are stated: Those arguing and those listening. This shows that some are motivated to argue their view/opinion/point while others prefer to be listeners or analyze and observe the situation. Thus, exhibiting that people in the crowd have different motivations.

The 'you' in the situation has not chosen a motivation yet as it is described that they cannot get close enough to hear the conversation/argument occurring.

Hope this helps!