Mental models are psychological representations of real, hypothetical, or imaginary situations. They were first postulated by the American philosopher Charles Sanders Peirce, who postulated (1896) that reasoning is a process by which a human
“examines the state of things asserted in the premisses, forms a diagram of that state of things, perceives in the parts of the diagram relations not explicitly mentioned in the premisses, satisfies itself by mental experiments upon the diagram that these relations would always subsist, or at least would do so in a certain proportion of cases, and concludes their necessary, or probable, truth.”
The Scottish psychologist Kenneth Craik (1943) proposed a similar idea; he believed that the mind constructs “small-scale models” of reality that it uses to anticipate events, to reason, and to underlie explanation. Like pictures in Wittgenstein’s (1922) “picture” theory of the meaning of language, mental models have a structure that corresponds to the structure of what they represent. They are accordingly akin to architects’ models of buildings, to molecular biologists’ models of complex molecules, and to physicists’ diagrams of particle interactions.
But, despite Craik’s insight, cognitive scientists took for granted that people reasoned based on the laws of symbolic logic until Phil Johnson-Laird published the book Mental Models in 1983. Johnson-Laird argued that the mind constructs mental models as a result of perception, imagination and knowledge, and the comprehension of discourse. Since Johnson-Laird formalized the theory, cognitive scientists began to study how children develop such models, how to design artifacts and computer systems for which it is easy to acquire a model, how a model of one domain may serve as analogy for another domain, and how models engender thoughts, inferences, and feelings.