Editing ACT-R (section)

===Early years: 1973–1990===
ACT-R is the ultimate successor of a series of increasingly precise models of human cognition developed by [[John Robert Anderson (psychologist)|John R. Anderson]].

Its roots can be backtraced to the original HAM (Human Associative Memory) model of memory, described by John R. Anderson and [[Gordon Bower]] in 1973.<ref>Anderson, J. R., & Bower, G. H. (1973). ''Human associative memory''. Washington, DC: Winston and Sons.</ref>  The HAM model was later expanded into the first version of the ACT theory.<ref>Anderson, J. R. (1976) ''Language, memory, and thought''. Mahwah, NJ: Lawrence Erlbaum Associates.  {{ISBN|0-89859-107-4}}.</ref>   This was the first time the procedural memory was added to the original declarative memory system, introducing a computational dichotomy that was later proved to hold in human brain.<ref>Cohen, N. J., & Squire, L. R. (1980). Preserved learning and retention of pattern-analyzing skill in amnesia: dissociation of knowing how and knowing that. ''Science'', ''210(4466)'', 207–210</ref> The theory was then further extended into the ACT* model of human cognition.<ref>Anderson, J. R. (1983). ''The architecture of cognition''. Cambridge, Massachusetts: Harvard University Press. {{ISBN|0-8058-2233-X}}.</ref>