The concept of inhibition plays a major role in cognitive psychology. In the present article, we review the evidence for the inhibition of task sets. In the first part, we critically discuss empirical findings of task inhibition from studies that applied variants of the task-switching methodology and argue that most of these findings—such as switch cost asymmetries—are ambiguous. In the second part, we focus on n—2 task-repetition costs, which currently constitute the most convincing evidence for inhibition of task sets. n—2 repetition costs refer to the performance impairment in sequences of the ABA type relative to CBA, which can be interpreted in terms of persisting inhibition of previously abandoned tasks. The available evidence suggests that inhibition is primarily triggered by conflict at selection of stimulus attributes and at the response level.

It is well known that conversation (e.g., on a cell phone) impairs driving. We demonstrate that the reverse is also true: Language production and comprehension, and the encoding of the products of comprehension into memory, are less accurate when one is driving. Ninety-six pairs of drivers and conversation partners engaged in a story-retelling task in a driving simulator. Half of the pairs were older adults. Each pair completed one dual-task block (driving during the retelling task) and two single-task control blocks. The results showed a decline in the accuracy of the drivers' storytelling and of their memory for stories that were told to them by their nondriving partners. Speech production suffered an additional cost when the difficulty of driving increased. Measures of driving performance suggested that the drivers gave priority to the driving task when they were conversing. As a result, their linguistic performance suffered.

Everyday action in the world requires the coordination of "where," "when," and "how" with "what." In late infancy, there appear to be changes in how these different streams of information are integrated into the sequential organization of action. An experiment with 12-, 15-, and 18-month-olds was conducted in order to determine the influence of object properties and locations on the sequential selection of targets for reaching. The results reveal a developmental trend from reach decisions' being influenced only by the spatial layout of locations to the overall pattern of reaching's being influenced by the global configuration of object properties to object properties' influencing the sequential decision of what to reach to next. This trend is a new finding regarding the development of goal-directed action in late infancy.

Previous research indicates relative independence between the ventral and dorsal visual pathways, associated with object and spatial visual processing, respectively. The present research shows that, at the individual-differences level, there is a trade-off, rather than independence, between object and spatial visualization abilities. Across five different age groups with different professional specializations, participants with above-average object visualization abilities (artists) had below-average spatial visualization abilities, and the inverse was true for those with above-average spatial visualization abilities (scientists). No groups showed both above-average object and above-average spatial visualization abilities. Furthermore, while total object and spatial visualization resources increase with age and experience, the trade-off relationship between object and spatial visualization abilities does not. These results suggest that the trade-off originates through a bottleneck that restricts the development of overall visualization resources, rather than through preferential experience in one type of visualization.

The nature of visual mental images is a topic that has puzzled neuroscientists, psychologists, and philosophers alike. On the one hand, mental images might preserve the 3-D properties of our perceptual world. On the other hand, they might be akin to 2-D pictures, such as photographs, paintings, or drawings. In the present study, 16 observers judged where real objects (Experiment 1) or photographs thereof (Experiment 2) were pointing. Both experiments contained a perception condition and an imagery condition. In Experiment 1, there was a significant difference between the pointing errors in the perception and the imagery conditions, whereas there was no such difference in Experiment 2. In imagined objects, actual photographs, and imagined photographs, the direction in which the objects pointed followed the observer, regardless of his or her vantage point. The results from this study extend the rotation effect, typically found in pictures, to the domain of mental imagery. We found the rotation effect in pictures and mental images alike, but not in direct perception of 3-D objects; thus, we provide evidence that mental images share main characteristics of 2-D pictures.

The attentional walk task was used to investigate the temporal properties of covert shifts of attention. Observers shifted attention within arrays of identical items in response to a series of auditory commands and reported the color of the final disk. The density of the arrays and the timing of the shift commands varied. Performance decreased as density increased, and the minimal amount of time needed to shift attention depended on the density of the display, varying from 350 to 750 msec. In addition, the observers were able to maintain attentional focus for at least 3,500 msec without a decline in performance, regardless of density. Thus, although the ability to maintain attention at a given position was found to be independent of the precision with which that location was def ined, more precise attentional shifts required more time to execute.

This research examined the influence of cue temporal predictability on inhibition of return (IOR) in a discrimination task. In exogenous attention experiments, the cue that summons attention is noninformative as to where the target will appear. However, it is predictive as to when it will appear. In previous work, it was demonstrated that temporal predictability does not influence IOR in detection tasks. In this work, it is shown that IOR is influenced by temporal predictability in discrimination tasks. Predictability was manipulated by using three stimulus onset asynchrony distributions: nonaging, aging, and accelerated aging. IOR was found when the cue predicted target appearance and was modulated by temporal information. In the nonaging distribution (in which the cue did not predict target appearance), there was no IOR.

The importance of social context in affecting attention has recently been highlighted by the finding that the presence of a passive, nonevaluative confederate can improve selective attention. The underlying mechanism, however, remains unclear. In this paper, we argue that social facilitation can be caused by distractor inhibition. Two distinct sources of evidence are provided from an experiment employing the Stroop task with and without social presence. First, analysis of the response time (RT) distribution indicates that interference is reduced at relatively long RTs. This is consistent with an inhibitory mechanism, whose effects build up slowly. Further support is provided by showing that social facilitation is prevented by using short response-to-stimulus intervals that are thought to reduce cognitive control processes.