External cognition is a branch of cognitive science with focuses predominately on role played by external representation (such as diagrams and textual descriptions) in human cognition and also the relationship between internal and external representations. A distinction is made between either language-based external representations (such as books) and graphic-based forms of external representations (such as diagrams and maps). Researchers focus on the cognitive processing involved when agents interact with external representations, the properties of internal and external structures and the cognitive benefits of different external representations. Historically, cognitive science has focused on processes taking place inside the mind, external cognition and external representation departs from traditional cognitive modelling by highlighting the importance of external representations in human cognition.
Source: Cooperative Technologies for Complex Work Settings
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