What is a unified theory of cognition?

For a full account, see Unified Theories of Cognition by Newell (PSY BH:N 044). book. Many of these points, as I said, are foreshadowed in the 20 questions paper. I find the book's style somewhat rambling: it's a lot easier to read a précis in Behavioural and Brain Sciences volume 15 page 425. This is followed by replies from Newell's critics.

According to Newell, a UTC is a single set of mechanisms that account for all of cognition (using the term broadly to include perception and motor control). For example, memory, problem solving, dreaming. Some of the things a UTC must explain are:

• How intelligent organisms respond flexibly to the environment.

• How they exhibit goal-directed behaviour and choose goals rationally (and in response to interrupts: see previous point).

• How they use symbols.

• How they learn from experience.

Why should psychologists want a UTC?

• The mind is a single system.

• The cognitive models we can devise are vastly underdetermined by experimental data: we need to add extra constraints. (I think what's meant by constraints here are the assumptions behind Soar's functional architecture.)

• If we have a UTC, then we can apply theoretical constructs to a much wider range of phenomena.