Representation is a term used in cognitive psychology, neuroscience, and cognitive science to refer to a hypothetical internal cognitive symbol that represents external reality. David Marr defines representation as "a formal system for making explicit certain entities or types of information, together with a specification of how the system does this."[1]Representationalism (also known as indirect realism) is the view that representations are the main way we access external reality.
Henrich, J. & Boyd, R. (2002). Culture and cognition: Why cultural evolution does not require replication of representations. Culture and Cognition, 2, 87?112. Full text