Editing ACT-R (section)

===Integration with rational analysis: 1990–1998===
In the late eighties, Anderson devoted himself to exploring and outlining a mathematical approach to cognition that he named [[Rational analysis]].<ref>Anderson, J. R. (1990) ''The adaptive character of thought''. Mahwah, NJ: Lawrence Erlbaum Associates. {{ISBN|0-8058-0419-6}}.</ref>  The basic assumption of Rational Analysis is that cognition is optimally adaptive, and precise estimates of cognitive functions mirror statistical properties of the environment.<ref>Anderson, J. R., & Schooler, L. J. (1991). Reflections of the environment in memory. ''Psychological Science'', ''2'', 396–408.</ref>   Later on, he came back to the development of the ACT theory, using the Rational Analysis as a unifying framework for the underlying calculations.  To highlight the importance of the new approach in the shaping of the architecture, its name was modified to ACT-R, with the "R" standing for "Rational" <ref>Anderson, J. R. (1993). ''Rules of the mind''. Hillsdale, NJ: Lawrence Erlbaum Associates. {{ISBN|0-8058-1199-0}}.</ref>

In 1993, [[John Robert Anderson (psychologist)|Anderson]] met with Christian Lebiere, a researcher in [[connectionism|connectionist models]] mostly famous for  developing with [[Scott Fahlman]] the [[Cascade correlation algorithm|Cascade Correlation]] learning algorithm.  Their joint work culminated in the release of ACT-R 4.0.<ref>Anderson, J. R., & Lebiere, C. (1998). ''The atomic components of thought''. Hillsdale, NJ: Lawrence Erlbaum Associates. {{ISBN|0-8058-2817-6}}.</ref> Thanks to Mike Byrne (now at [[Rice University]]), version 4.0 also included optional perceptual and motor capabilities, mostly inspired from the EPIC architecture, which greatly expanded the possible applications of the theory.