People are more likely to think that people from their own groups (e.g. similar class standing) are likely to agree with their opinions rather than people from different groups (e.g. different class standings). The more similar we are to a group, the more likely we are to expect individual members of that group to make similar choices, have similar beliefs, and attitudes. In other words, someone is more likely to project their own qualities to someone if they some have similar characteristics (e.g. both freshman at the same college) rather than different characteristics (e.g. freshman at two different colleges).