Competitive Learning: From Interactive Activation to Adaptive Resonance

Functional ond mechanistic comparisons are mode between several network models of cognitive processing: competitive learning, interactive activation, adaptive resonance, and back propagation. The starting point of this comparison is the article of Rumelhart ond Zipser (1985) on feature discovery through competitive learning. All the models which Rumelhart and Zipser (1985) have described were shown in Grossberg (1976b) to exhibit a type of learning which is temporally unstable. Competitive learning mechanisms con be stabilized in response to an arbitrary input environment by being supplemented with mechanisms for learning top-down expectancies, or templates; for matching bottom-up input patterns with the top-down expectancies; and for releasing orienting reactions in o mismatch situation, thereby updating short-term memory ond searching for another internal representation. Network architectures which embody all of these mechonisms were called adaptive resonance models by Grossberg (1976~). Self-stabilizing learning models are candidates for use in real-world applications where unpredictable changes can occur in complex input environments. Competitive learning postulates ore inconsistent with the postulates of the interactive activotion model of McClelland and Rumelhart (1981). and suggest different levels of processing and interaction rules for the analysis of word recognition. Adaptive resonance models use these alternative levels and interaction rules. The selforganizing learning of on odaptive resonance model is compared ond contrasted with the teacher-directed learning of a back propagation model. A number of criteria for evaluating reol-time network models of cognitive processing ore described and applied.