Working Memory in a Multilevel Hybrid Connectionist Control Architecture (CAP2)
Walter Schneider · Cambridge University Press eBooks · 1999
FIVE CENTRAL FEATURES OF THE THEORY In a connectionist control network, working memory is implemented via short-term activation and connection changes that support cognitive operations. The CAP2 approach is a model of skilled processing and learning. When applied to working memory the model instantiates multiple forms and mechanisms of working memory. The major features are: (1) Memory and processing occur in a multilayered hierarchy of modular processors with limited interactions and a single executive modulating activity. The CAP2 micro- and macrostructural characteristics and temporal expectations show parallels in cortical architecture and activation patterns. (2) Memory takes the form of activation vectors in modules, fast and slowly changing connection weights within and between modules with different activation, interference, and decay effects. (3) The control and regulation of working memory is performed by a hierarchical control structure of an executive using activity and priority reports from the network of modules and input of messages on the inner loop to monitor and modulate message traffic. (4) The executive is a limited sequential processing network that can execute the production system–like sequential operations, which are particularly critical in learning new tasks and maintaining temporary variable information that is not coded in consistent association patterns in the modular network. The executive has local memory to maintain variable bindings and sequential procedures to control the network to perform cognitive tasks. (5) Skilled performance involves automatic module-to-module transmissions that can perform consistent associative mappings with little loading of the executive.