The dual-stage two-phase (DSTP) model is introduced as a formal and general model of selective attention that includes both an early and a late stage of stimulus selection. Whereas at the early stage information is selected by perceptual filters whose selectivity is relatively limited, at the late stage stimuli are selected more efficiently on a categorical basis. Consequently, selectivity is first low but then abruptly increases during the course of stimulus processing. Although intended as a general model of selective attention, in the present study the DSTP model was applied to account for the distributional data of 3 flanker task experiments. The fit of the model to the data was not only rather good but also superior to those of alternative single-stage models with a continuously increasing selectivity. All together, the model provides a comprehensive account of how early and late stages of attention interact in the control of performance.

Repetition effects are often helpful in revealing information about mental structures and processes. Usually, positive effects have been observed when the stimuli or responses are repeated. However, in task shift studies it has also been found that response repetitions can produce negative effects if the task shifts. Although several mechanisms have been proposed to account for this interaction between task shifting and response repetition, many details remain open. Therefore, a series of four experiments was conducted to answer two questions. First, are motor responses necessary to produce response-related repetition effects, or is response activation sufficient? Second, does the risk of an accidental re-execution of the last response affect the repetition costs? The results show that response activation alone can produce repetition effects. Furthermore, the risk of accidental response re-execution largely modulates these effects.

It has been suggested that performance in the Stroop task is influenced by response conflict as well as task conflict. The present study investigated the idea that both conflict types can be isolated by applying ex-Gaussian distribution analysis which decomposes response time into a Gaussian and an exponential component. Two experiments were conducted in which manual versions of a standard Stroop task (Experiment 1) and a separated Stroop task (Experiment 2) were performed under task-switching conditions. Effects of response congruency and stimulus bivalency were used to measure response conflict and task conflict, respectively. Ex-Gaussian analysis revealed that response conflict was mainly observed in the Gaussian component, whereas task conflict was stronger in the exponential component. Moreover, task conflict in the exponential component was selectively enhanced under task-switching conditions. The results suggest that ex-Gaussian analysis can be used as a tool to isolate different conflict types in the Stroop task.

The hypothesis is introduced that 1 source of shift costs is the strengthening of task-related associations occurring whenever an overt response is produced. The authors tested this account by examining shift effects following errors and error compensation processes. The authors predicted that following a specific type of error, called task confusion, shift benefits instead of shift costs should result. A series of 3 experiments confirmed this prediction showing that task confusions produce shift benefits in subsequent trials (Experiment 1), even when the error is detected (Experiment 2). Moreover, only posterror processes that imply an error correction response produce shift costs (Experiment 3). These results additionally suggest that error detection cannot prevent errors from affecting subsequent performance.

It is widely assumed that supervisory or attentional control plays a role only in the preparatory reconfiguration of the mental system in task shifting. The well-known fact that residual shift costs are still present even after extensive preparation is usually attributed to passive mechanisms such as cross talk. The authors question this view and suggest that attentional control is also responsible for residual shift costs. The authors hypothesize that, under shift conditions, tasks are executed in a controlled mode to guarantee reliable performance. Consequently, the control of 2 task components should require more resources than the control of only 1. A series of 4 experiments with 2-component tasks was conducted to test this hypothesis. As expected, more residual shift costs were observed when 2 components rather than 1 varied across trials. Interference effects and sequential effects could not account for these results.

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This article presents and tests the authors' integration hypothesis of global/local processing, which proposes that at early stages of processing, the identities of global and local units of a hierarchical stimulus are represented separately from information about their respective levels and that, therefore, identity and level information have to be integrated at later stages. It further states that the cerebral hemispheres differ in their capacities for these binding processes. Three experiments are reported in which the integration hypothesis was tested. Participants had to identify a letter at a prespecified level with the viewing duration restricted by a mask. False reporting of the letter at the nontarget level was predicted to occur more often when the integration of identity and level could fail. This was the case. Moreover, visual-field effects occurred, as expected. Finally, a multinomial model was constructed and fitted to the data.

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