Symbols in computer programs are not necessarily isomorphic in form or capability to neural processes. Representations in our models are stored descriptions of the world and human behavior, created by a human interpreter; representations in the brain are neither immutable forms nor encoded in some language. Although the term " symbol " can be usefully applied to describe words, smoke signals, neural maps, and graphic icons, a science of symbol processing requires distinguishing between the structural, developmental, and interactive nature of (...) different forms of representing. (shrink)

The MER created a virtual experience of being on Mars. This book examines how the MER has changed the nature of planetary field science.

In the 1970s, we conceived of a rule explanation as supplying the causal and social context that justifies a rule, an objective documentation for why a rule is correct. Today we would call such descriptions post-hoc design rationales, not proving the rules? correctness, but providing a means for later interpreting why the rule was written and facilitating later improvements.

Information processing theories of memory and skills can be reformulated in terms of how categories are physically and temporally related, a process called conceptual coordination. Dreaming can then be understood as a story-understanding process in which two mechanisms found in everyday comprehension are missing: conceiving sequences (chunking categories in time as a higher-order categorization) and coordinating across modalities (e.g., relating the sound of a word and the image of its meaning). On this basis, we can readily identify isomorphisms between dream (...) phenomenology and neurophysiology, and explain the function of dreaming as facilitating future coordination of sequential, cross-modal categorization (i.e., REM sleep lowers activation thresholds, “unlearning”). [Hobson et al.; Nielsen; Solms; Revonsuo; Vertes & Eastman]. (shrink)

van der Velde's &de Kamps's neural blackboard architecture is similar to “activation trace diagrams” (Clancey 1999), which represent how categories are temporally related as neural activations in parallel-hierarchical compositions. Examination of other comprehension examples suggests that a given syntactic categorization (structure assembly) can be incorporated in different ways within an open composition by different kinds of anchoring relations (delay assemblies). Anchors are categorizations, too, so they cannot be reused until their containing construction is completed (bindings are resolved).

“Conceptual coordination” analysis bridges connectionism and symbolic approaches by positing a “process memory” by which categories are physically coordinated in time. Focusing on dysfunctions and odd behaviors, like slips, reveals the function of consciousness, especially constructive processes that are often taken for granted, which are different from conventional programming constructs. Newell strongly endorsed identifying architectural limits; the heuristic of “diagnose unusual behaviors” will provide targets of opportunity that greatly strengthen the Newell Test.

Knowledge engineers once viewed themselves as priests; they received "The Word" from experts above, added nothing to the content, but codified it accurately into written rules, and passed it down to ordinary folks as commandments to live by.