Ph.D., University of Rochester, 1991


Computational Cognition Lab web site

I am fascinated by how meaning can be extracted from the language environment.  In the Computational Cognition Lab, we explore this problem at the cognitive, neural, and computational levels. Consequently, my research explores the memory mechanisms that underlie language comprehension, the processing of semantic and syntactic ambiguity, as well as figurative language.

A longstanding area of research in my lab involves characterizing the complementary roles of the cerebral hemispheres in language comprehension by investigating memory function using both normal, computational, and brain-damaged subject populations. With respect to lexical/semantic processing, we have gathered considerable evidence that the two hemispheres differ in the rate of meaning activation, but do not differ much at a representational level. Our goal is to fit these findings in the context of our basic psycholinguistic understandings of how we comprehend ongoing discourse. At the word recognition level, we have developed a computational implementation of cerebral asymmetries that makes use of our Hyperspace Analogue to Language model.

Our most recent project has been the development of the Hyperspace Analogue to Language (or HAL), which is a computer simulation of human memory. HAL has a lexicon of 70,000 items and learns its representations as a function of the contexts in which words occur. This is accomplished with a concept-acquisition process that requires no supervision using an input of 320 million words of text. Word meanings (broadly based) are represented in a 140,000 dimensional space (thus, Hyperspace Analogue to Language). The model accounts for a wide range of semantic, language, grammatical, and syntactic phenomena. New areas of exploration for the model involve commercial and forensic applications as well as memory disorders in deep dyslexia, schizophrenia, Alzheimer’s and normal aging, deception, web semantics, and dolphin language.

Check out my lab's web pages for more information on my research, reprints, what my students are up to, photos of lab facilities, and a HAL demo.

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