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Recent research (e.g., Siegler, 1996) has discovered the important and vital role that variability plays among strategy use and development over time. However, as many researchers have pointed out (e.g., Miller, 1993), the majority of the research addressing this issue has focused on the outcomes, rather than on the potentially more informative aspects of variability, strategy development, and the process of adaptation. In this study, we examined the role of variability during strategy development, utilizing a longitudinal method. Thirteen participants were studied over 3 months as they coached a simulated football team. The results suggest that variability plays a major role in adaptive skill acquisition in a dynamic environment--in the direction, however, opposite to that predicted by previous research done with simple static tasks.

The explicit task-cuing procedure involves presenting a cue that indicates which task to perform on a target. Responses are typically faster when tasks repeat than when they alternate, and this difference is often interpreted as a measure of the time required for executive control processes to change task set. This article suggests that the difference reflects priming of cue encoding when successive cues are identical or associatively related. Subjects responded to task repetitions more quickly when the cue on the current trial was associatively related to the cue on the previous trial (e.g., day [right arrow] night) than when the cues were unrelated (e.g., verb [right arrow] night). Models applied to the time course function--generated by manipulating the interval between the onsets of the cue and the target--showed that the facilitation was due to cue encoding, a process that does not require online executive control.

The article describes a simulated 'cooking breakfast' task in which participants must remember to start and stop cooking five foods so that all the foods are 'ready' at the same time. In between starting and stopping operations, the participants also carried out a 'table-setting' task as a filler activity. The breakfast task yields various measures of multitasking and executive control. Groups of younger and older adults performed the task; half of the participants in each group were bilinguals and the other half were monolinguals. The results showed substantial age-related decrements in most measures of executive control. Additionally, older bilinguals showed some advantages in task management over their monolingual peers.

The intention superiority effect (ISE) is characterized by faster response time to task material intended for future performance than to neutral material with no associated intention or material that is linked to a canceled intention. The existence of the ISE has been explored here under naturalistic conditions in which participants self-initiate an intention that is of personal relevance to them. Participants were required to remember prospective tasks that were presented under the guise of preparatory tasks for the next participant. After encoding a pair of tasks, they were informed that one task no longer needed to be performed. Subsequent lexical decision data exhibited the expected effect of faster response time for intended items than for canceled items (experimental groups in Experiments 1A and 1B). No differences in response time were observed between two sets of canceled items (control group in Experiment 1A). When an intention coexisted with the expectation that a written description of the task would be available, no reliable difference in latencies for these items and canceled items was observed (control group in Experiment 1B). The results are discussed in terms of facilitatory and inhibitory processes that may allow us to contend with many intentions in everyday scenarios.

In three experiments that used levels of processing and study time manipulations as independent variables in a word fragment completion task, the validity of the assumption of independence between recollection and automatic influences of memory was assessed. This assumption underlies the use of the process dissociation procedure (Jacoby, 1991), a tool suggested for distinguishing the different contributions of recollection and automatic influences of memory. Overall, it appeared that semantic processing, as compared with physical processing at study, positively affected recollection but negatively affected automatic influences of memory in word fragment completion. This negative effect on the automatic influences was reduced when the available study time decreased. The incompatibility of these results with the assumption of independence between recollection and automatic influences of memory and their impact on the applicability of the process dissociation procedure are discussed.

Do deeper levels of processing produce equivalent priming effects at all stages of task performance? In Experiment 1, we varied the level of processing factorially across two task stages--target selection and response selection. Each stage required perceptual (e.g., color) or conceptual (e.g., friendliness) processing of stimulus items (i.e., animal names). Negative priming was substantially greater when deeper processing was required at the target selection stage, but it was unaffected by the level of processing at the response selection stage. In contrast, positive priming was greater when deeper processing was required at the response selection stage, but it was unaffected by processing at the target selection stage. In Experiment 2, we generalized this finding using a task in which numeric targets were selected on the basis of their parity. As in Experiment 1, the deeper level of processing at the target selection stage produced a larger negative priming effect. These results illuminate the role of target selection demands in modulating the strength of negative priming.