When mary jane steps into the elevator, she immediately glances at the other passengers and decides that the gray-haired man with the beard must be a professor at the college. mary jane engaged in the process of: ?

I believe the answer is: social categorization.
social categorization refers to the process of relating a certain characteristics that held by individuals to predict their status in the social group.
In the scenario above, jane's perception is completely logical because the old individuals that wears glases (glasses indicates someone that reads)  in university lift are very likely to be a professor.