Some analogies of schema

A schema is like many things, and these analogies may provide a better understanding about the concept of schema.

1. A schema is like a sorting device.
     A sorting device allows us to place some objects in one category and the rest in another, just as schema allows us to determine that some stimuli are instantiation and others are not.

2. A schema is like a play.
    A play has various parts; the roles are played by actors. these roles can be filled by many different people, just as a schema's slot can be filled with many different stimuli. The part of a play relates to each other as specified by the script, just as a schema specifies relations between parts. A play's instantiation is a specific performance, just as an instantiation of the face  schema is a certain face. A performance of a play is unlike any other, just as no face is quite the same as another. A play should also has a room for variation. It is often organized around a theme, such as marriage or coming of age.

3. A schema is like a filter.
    It allows some information in but not all.