Trying to explain schema theory at our recent summer school, I mentioned these two examples. The first is the user guide developed by Sainsbury's in the early 1950s to explain to customers how self-service shopping works. The second is an early set of instructions about how to use a telephone.
Source: I scanned this from an article in Sainsbury's customer magazine some years ago, but have lost track of the citation.
Source: the BT museum.
Schemas* are mental structures that we use to organise knowledge. We try to fit new information into our existing schemas, and we bring our existing world knowledge into play as we interpret any information. Schema theory is associated with the psychologist Frederic Bartlett, and it is also central to the work of the child psychologist Jean Piaget, who saw schemata as the basic building blocks of thinking.
Bartlett, F.C. (1932), Remembering: An Experimental and Social Study. Cambridge: Cambridge University Press
* yes, the correct plural is really 'schemata' as it's from the Greek, but the anglicised version in increasingly common and less show-offy.