Professor, Psychology & Computer Science Carnegie Mellon University Phone: (412) 268-5145 Email: plaut@cmu.edu Individual Website: http://www.cnbc.cmu.edu/~plaut/

Ph.D., Carnegie Mellon University

Research Interests

My research involves using computational modeling, complemented by empirical studies, to investigate the nature of normal and disordered cognitive processing in the domains of reading, language, and semantics. My modeling work is cast within a connectionist or parallel distributed processing framework, in which cognitive processes are implemented in terms of cooperative and competitive interactions among large numbers of simple, neuron-like processing units. These models provide new ways of thinking about how cognitive processes are implemented in the brain, and how disorders of brain function lead to disorders of cognition. I'm particularly interested in studying the effects of damage in connectionist networks as a way of understanding the nature of cognitive impairments that can arise following brain damage, and in exploring ways of retraining damaged networks with the goal of helping to design more effective strategies for patient rehabilitation. I'm also interested in the implications of connectionist learning principles for the nature of normal and abnormal cognitive development.

Much of my work has focused on word reading, both in normal skilled readers and in brain-damaged patients with acquired reading disorders. My colleagues and I have developed connectionist models that exhibit many of the central characteristics of skilled reading, including the influences of word frequency and spelling-sound consistency on the time to pronounce words and the ability to pronounce word-like nonsense letter strings (e.g., MAVE) and to distinguish them from real words in lexical decision tasks (Plaut, 1997; Plaut et al., 1996). When the models are damaged in various ways, they exhibit the major forms of acquired dyslexia, including deep dyslexia in which patients make semantic errors in reading aloud (e.g., misreading YACHT as "boat") and surface dyslexia in which patients produce regularization errors to exception words (e.g., misreading YACHT as "yatched") (Plaut, 1997; Plaut & Shallice, 1993; Plaut et al., 1996). Moreover, retraining the damaged models yields patterns of recovery and generalization that are qualitatively similar to those found in cognitive rehabilitation studies and has, in one instance, generated a specific prediction concerning the design of more effective therapy for patients (Plaut, 1996) that has recently received empirical support (Kiran & Thompson, 2003).

Although our work on reading continues (e.g., Kello & Plaut, 2000, 2003, Woollams et al., 2007), I have also begun to extend my work to address other issues in language processing, including: 1) early language acquisition and the development of phonological representations through the interplay of speech comprehension and production (Plaut & Kello, 1999; Kello & Plaut, 2004); 2) cross-linguistic differences in morphological processing (Plaut & Gonnerman, 2000; Velan et al., 2005); 3) semantic and associative priming effects in naming and lexical decision (Plaut & Booth, 2000, 2006); 4) patterns of semantic impairments among brain-damaged patients, and their implications for the degree of functional specialization within the semantic system (Gotts & Plaut, 2002; Plaut, 2002); and 5) sentence-level acquisition and processing and the interplay of syntax and semantics (Rohde & Plaut, 1999, 2003). Additional work extends the same computational principles to issues in normal and impaired routine sequential action (Botvinick & Plaut, 2004) and to verbal short-term memory (Botvinick & Plaut, 2006).

Recent Publications

• Woollams A, Lambon Ralph MA, Plaut DC, Patterson K: SD-squared: On the association between semantic dementia and surface dyslexia. Psychol Rev 114: 316-339, 2007.
• Botvinick M, Plaut DC: Short-term memory for serial order: A recurrent neural network model. Psychol Rev 113: 201-233, 2006.
• Botvinick M, Plaut DC: Doing without schema hierarchies: A recurrent connectionist approach to normal and impaired routine sequential action. Psychol Rev 111: 395-429, 2004.
• Plaut DC: Graded modality-specific specialization in semantics: A computational account of optic aphasia. Cogn Neuropsychol 19: 603-639, 2002.
• Plaut DC, Booth JR: Individual and developmental differences in semantic priming: Empirical and computational support for a single-mechanism account of lexical processing. Psychol Rev 107: 786-823, 2000.
• Plaut DC, McClelland JL, Seidenberg MS, Patterson K: Understanding normal and impaired word reading: Computational principles in quasi-regular domains. Psychol Rev 103: 56-115, 1996.