Goal‐directed cognition is often discussed in terms of specialized memory structures like the “goal stack.” The goal‐activation model presented here analyzes goal‐directed cognition in terms of the general memory constructs of activation and associative priming. The model embodies three predictive constraints: (1) the interference level, which arises from residual memory for old goals; (1) the strengthening constraint, which makes predictions about time to encode a new goal; and (3) the priming constraint, which makes predictions about the role of cues in (...) retrieving pending goals. These constraints are formulated algebraically and tested through simulation of latency and error data from the Tower of Hanoi, a means‐ends puzzle that depends heavily on suspension and resumption of goals. Implications of the model for understanding intention superiority, postcompletion error, and effects of task interruption are discussed. (shrink)

Veksler and Gunzelmann make an extraordinary claim, which is that sleep deprivation effects and the vigilance decrement are functionally equivalent. Extraordinary claims require extraordinary evidence, which is missing from Veksler and Gunzelmann's study. Their behavioral data offer only weak theoretical constraint, and to the extent their modeling exercise supports any position, it is that these two performance impairments involve functionally distinct underlying mechanisms.

The notion of functionality is appropriately central to the Newell Test but is also critical at a lower level, in development of cognitive sub-theories. I illustrate, on one hand, how far this principle is from general acceptance among verbal theoreticians, and, on the other hand, how simulation models (here implemented within ACT-R) seem to drive the functional question automatically.