Michael Ullman, PhD

Associate Professor
Department of Neuroscience
D237B Building D, Box 571464
3900 Reservoir Rd, NW
Georgetown University
Washington DC 20057 
Phone: 202 687-6064
Fax: 202 687-6914

Research Interests

Sex differences and the effects of sex hormones in the neurocognition of memory and language

Research Summary

My research examines the neurocognitive bases of language. The research focuses on two fundamental capacities of language: the “mental lexicon” (mental dictionary) of memorized words, and the “mental grammar,” which underlies the rule-governed sequential and hierarchical combination of lexical forms into complex words (e.g., walk + -ed), phrases and sentences. Previous neurocognitive models of lexicon and grammar have had difficulty integrating knowledge across the relevant disciplines, in particular neuroscience, psychology and linguistics. According to the “declarative/procedural” model that my colleagues and I have proposed, lexicon and grammar depend respectively upon two well-studied brain memory systems (e.g., see Ullman, 2001, Nature Reviews Neuroscience).

Lexical memory depends on declarative memory, which underlies the learning and use of fact and event knowledge, and is rooted largely in temporal lobe structures. Aspects of grammar involve procedural memory, which subserves the acquisition and expression of motor and cognitive skills (e.g., riding a bicycle); it may be specialized for sequences and is rooted largely in frontal/basal-ganglia structures. My colleagues and I have examined the predictions of this novel model, in comparison to those of competing models, with numerous approaches, including neuropsychological studies of developmental and adult-onset disorders and with neuroimaging.

Recent work in our lab suggests intriguing sex differences, with potentially important educational and clinical implications. Previous studies have shown that women are superior to men at remembering new words, and that this ability likely depends on declarative memory and estrogen. We predicted and have found that women tend to store, in lexical/declarative memory, complex linguistic forms that men normally compute on-line in the grammatical/procedural system (e.g., walked). Moreover, our evidence suggests that this effect is modulated at least in part by estrogen. Converging evidence has thus far been obtained from seven experiments, using psycholinguistic, neuropsychological, and neuroimaging techniques, including a hormone replacement study, in English and Spanish, testing morphology and syntax, in both expressive and receptive language.

Representative Publications
  • Ullman, M. T. (2001). A neurocognitive perspective on language: The declarative/procedural model. Nature Reviews Neuroscience, 2, 717-726.
  • Ullman, M. T. (2001). The neural basis of lexicon and grammar in first and second language: The declarative/procedural model. Bilingualism: Language and Cognition, 4(1), 105-122.
  • Estabrooke, I. V., Mordecai, K., Maki, P. M., & Ullman, M. (2002). The effect of sex hormones on language processing. Brain and Language, 83, 143-146.
  • Pinker, S., & Ullman, M. T. (2002). The past and future of the past tense. Trends in Cognitive Sciences, 6(11), 456-463.
  • Ullman, M. T., Estabrooke, I. V., Steinhauer, K., Brovetto, C., Pancheva, R., Ozawa, K., Mordecai, K., & Maki, P. M. (2002). Sex differences in the neurocognition of language. Brain and Language, 83, 9-224.