Definition
This is a concept of self that is prevalent in social groups, someone who uses this assumes what others would think about themselves and uses those assumptions to guide what they do. This definition of self is sometimes upheld by others reactions but more often is just based on what someone thinks that others think about them. This idea was used by Charles Cooley in 1902, and is used to explain why people look for compliments and are effected by insults.

Example
I see many people who instead of worrying about how they think they look are more interested in how others perceive them, I know I also act this way and understand that it helps to facilitate bad peer pressure.

Image of 2 people, one with cloud above containing image of 2 people in picture