2003-05-19Z2011-03-11T08:55:17Zhttp://cogprints.org/id/eprint/2960This item is in the repository with the URL: http://cogprints.org/id/eprint/29602003-05-19ZCognitive Science and PsychologyThe protocol algorithm abstracted from a human cognizer's own narrative in the course of doing a cognitive task is an explanation of the corresponding mental activity in Pylyshyn's (1984) virtual machine model of mind. Strong equivalence between an analytic algorithm and the protocol algorithm is an index of validity of the explanatory model. Cognitive psychologists may not find the index strong equivalence useful as a means to ensure that a theory is not circular because (a) research data are also used as foundation data, (b) there is no justification for the relationship between a tobevalidated theory and its criterion of validity, and (c) foundation data, validation criterion and tobevalidated theory are not independent in cognitive science. There is also the difficulty with not knowing what psychological primitives are.Dr Siu L. Chow