In an investigation of task-set reconfiguration, participants switched between 2 tasks on every 2nd trial in 5 experiments and on every 4th trial in a final experiment. The tasks were to classify either the digit member of a pair of characters as even/odd or the letter member as consonant/vowel. As the response-stimulus interval increased up to 0.6 s, the substantial cost to performance of this predictable task-switch fell: Participants could partially reconfigure in advance of the stimulus. However, even with 1.2 s available for preparation, a large asymptotic reaction time (RT) cost remained, but only on the 1st trial of the new task. This is attributed to a component of reconfiguration triggered exogenously, i.e., only by a task-relevant stimulus. That stimuli evoke associated task-sets also explains why RT and switch costs increased when the stimulus included a character associated with the currently irrelevant task.

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In 6 task-cuing experiments, with 2 cues per task, the authors varied cue-stimulus interval to investigate G. D. Logan and C. Bundesen's (2003) claim that when cue repetition is controlled for, task-switch cost and its reduction with preparation are largely eliminated and hence cannot index an endogenous control process. Experiment 1 replicates their result, but Experiments 2 and 3, with similar designs, demonstrate a substantial task-switch cost, reducing with increasing cue-stimulus interval. Experiments 4 to 6 show that the critical difference is the probability of a task change: If it is kept low enough to discourage reconfiguration of task set unless and until the cue signals a task change, robust evidence for anticipatory task-set reconfiguration is obtained, even in Experiment 6, modeled closely on Logan and Bundesen's.

Compared the effect of frequency on lexical decision time (LDT) with that on reaction time (RT) in four other tasks, for the same words and subjects. Exp. 1 yielded an effect on semantic categorization RT (person vs. thing) similar in size and form to the effect on LDT. Exp. 2 yielded a substantial effect for syntactic categorization (noun vs. adjective), although weaker than the effect on LDT. In Exp. 3, the effect on naming RT for stress-final disyllabic words was identical to that on LDT, whereas the effect for stress-initial words was weaker. Exp. 4 showed no effect of frequency on delayed naming RT. The data undermine recent arguments for a (mainly) postidentification task-specific locus of frequency effects but are compatible with the older assumption (also characteristic of new PDP learning models) that lexical identification is a major locus of frequency effects (perhaps together with retrieval of meaning or phonology). But effects at that locus may be masked or diluted by other processes.