photo of David O'BrienDavid O'Brien

Phone: (646) 312- 3791

Location: VC 8-224


David O'BrienProfessor of Psychology; BA, Boston University; PhD, Temple University

David O’Brien’s research program investigates declarative knowledge, i.e., knowledge that can be expressed with linguistic propositions, beginning with the epistemological assumption that in order to store declarative knowledge in memory, there must be a representational format with which to store it. This format must be capable of representing properties and the things that have those properties and to distinguish between the two, and to keep track of which things have which properties and vice versa. In other words, the mind must have some basic logical predicate/argument structure. Further, the mind should have some ways of representing alternatives among properties or the entities that have those properties, as well as conjunctions, suppositions, and negations — the sorts of things that are done, for example, with English-language words such as or , and , if , and not . These assumptions are the basis for the “mental-logic” theory O’Brien co-developed with the late Martin Braine of New York University.

The basic research approach could be called “experimental epistemology,” because it brings the methods of experimental psychology to bear on these epistemological issues. The idea is to discover what is psychologically basic in such knowledge, and this goal requires investigating not only the thinking of adults, but also addressing what sorts of representational formats and inferences are available early in development and across languages and cultures. O’Brien thus engages in empirical research across a varied set of populations, including children, and deaf and illiterate populations in Portuguese-speaking Brazil. Recently he has been engaged in setting-up research projects with recently discovered indigenous groups in the northwestern Amazon basin. In addition, he remains engaged in more traditional research in his laboratory located in the Psychology Department at Baruch College. He welcomes inquiries from students who are interested or curious about gaining research experience working in his laboratory and can be reached by email at:

Representative Publications:

    [Mental Logic book cover]
  • O’Brien, D.P., and Bonatti, L.L. (1999). The semantics of logical connectives and mental logic. Cahiers de Psychologie Cognitive (Current Psychology of Cognition) , 18 , 87-97.
  • O’Brien, D.P., Dias, M.G., and Roazzi, A. (1998). A case study in the mental-logic and mental-models debate: Conditional syllogisms. In M.D.S. Braine and D.P. O’Brien (Eds.) Mental logic . pp. 385-420. Mahwah, NJ: Lawrence Erlbaum Associates.
  • O’Brien, D.P., Dias, M.G., Roazzi, A., and Braine, M.D.S. (1998). Conditional reasoning: The logic of supposition and children’s understanding of pretense. In M.D.S. Braine and D.P. O’Brien (Eds.) Mental logic . pp. 245-272. Mahwah, NJ: Lawrence Erlbaum Associates.
  • O’Brien, D.P., Dias, M.G., Roazzi, A., and Cantor, J. (1998). Pinocchio’s nose knows: Preschool children recognize that a pragmatic rule can be violated, an indicative conditional can be falsified, and that a broken promise is a false promise. In M.D.S. Braine and D.P. O’Brien (Eds.), Mental logic . pp. 447-472. Mahwah, NJ: Lawrence Erlbaum Associates.
  • O’Brien, D.P., Braine, M.D.S., and Yang, Y. (1994). Propositional reasoning by models? Simple to refute in principle and in practice. Psychological Review , 101, 711-724.
  • Braine, M.D.S., and O’Brien, D.P. (1991). A theory of if: A lexical entry, reasoning program, and pragmatic principles. Psychological Review , 98, 182-203. Reprinted in M.D.S. Braine and D.P. O’Brien (Eds.), Mental logic . (1998).
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