Allen Newell

Allen Newell was Simon's principal collaborator across the most productive research partnership in the history of cognitive science. Their work together produced the Logic Theorist (1955) — widely considered the first artificial intelligence program — the General Problem Solver (1957), the theory of human problem-solving articulated in their 1972 magnum opus, and the unified architecture of cognition that Newell developed in his later career. Newell's contribution to Simon's framework was methodological as well as substantive: he insisted that cognitive theories be expressible as running computer programs, and that the programs be empirically tested against human performance on carefully chosen tasks. The collaboration established the methodology that became standard in cognitive science — protocol analysis, computational modeling, and the integration of psychological experiment with formal theory. Newell's 1990 book Unified Theories of Cognition represents his own synthesis of the research program he and Simon had pursued for thirty-five years, offering a comprehensive architecture for understanding cognition from the millisecond scale of neural processes to the multi-year scale of learning