The ACT-R distribution contains all the files needed to run ACT-R models and develop custom task environments. The Macintosh distribution includes an OS X-style application with a standard Macintosh look and feel. The Windows/Linux distribution includes a double-clickable Java archive (JAR) file that launches the application; you will need to install Java on your system if you have not already (Windows/Linux only). All distributions include an archive file for custom coding, a user's manual, and a set of ACT-R tutorial models (derived from those used in the CMU ACT-R tutorials).
The development distribution below represents the most recent, though not necessarily stable, build of the system.
The source code is also available for advanced users who are interested in modifying the cognitive architecture and/or the development environment.