Unified Theories of Cognition

Unified Theories of Cognition is a 1990 book by Allen Newell. Newell argues for the need of a set of general assumptions for cognitive models that account for all of cognition: a unified theory of cognition, or cognitive architecture. The research started by Newell on unified theories of cognition represents a crucial element of divergence with respect to the vision of his long-term collaborator, and AI pioneer, Herbert Simon for what concerns the future of artificial intelligence research. Antonio Lieto recently drew attention to such a discrepancy, by pointing out that Herbert Simon decided to focus on the construction of single simulative programs (or microtheories/"middle-range" theories) that were considered a sufficient mean to enable the generalisation of “unifying” theories of cognition  (i.e. according to Simon the "unification" was assumed to be derivable from a body of qualitative generalizations coming from the study of individual simulative programs). Newell, on the other hand, didn’t consider the construction of single simulative microtheories a sufficient mean to enable the generalisation of “unifying” theories of cognition and, in fact, started the enterprise of studying and developing integrated and multi-tasking intelligence via cognitive architectures that would have led to the development of the Soar cognitive architecture.

Contents
Newell argues that the mind functions as a single system. He also claims the established cognitive models are vastly underdetermined by experimental data. By cognition, Newell means:


 * Problem solving, decision making, routine action
 * Memory, learning, skill
 * Perception, motor behavior
 * Language
 * Motivation, emotion
 * Imagining, dreaming, daydreaming

After arguing in favor of the development of unified theories of cognition, Newell puts forward a list of constraints to any unified theory, in that a theory should explain how a mind does the following:


 * 1) Behave flexibly as a function of the environment
 * 2) Exhibit adaptive (rational, goal-oriented) behavior
 * 3) Operate in real time
 * 4) Operate in a rich, complex, detailed environment (Perceive an immense amount of changing detail; use vast amounts of knowledge; and control a motor system of many degrees of freedom)
 * 5) Use symbols and abstractions
 * 6) Use language, both natural and artificial
 * 7) Learn from the environment and from experience
 * 8) Acquire capabilities through development
 * 9) Operate autonomously, but within a social community
 * 10) Be self-aware and have a sense of self
 * 11) Be realizable as a neural system
 * 12) Be construable by an embryological growth process
 * 13) Arise through evolution

Newell's secondary task is to put forward the cognitive architecture Soar as an implementation of a UTC that meets the constraints above. Other efforts at unified theories of cognition cited in the book include ACT-R and the human processor model.