Contingent attentional capture occurs by activated target congruence

Contingent attentional capture occurs when a stimulus property captures an observer's attention, usually related to the observer's top-down attentional set for target-defining properties. In this study, we examined whether contingent attentional capture occurs for a distractor that does not share the target-defining property at a physical level, but does share that property at an abstract level of representation. In a rapid serial visual presentation stream, we defined the target by color (e.g., a green-colored Japanese kanji character). Before the target onset, we presented a distractor that referred to the target-defining color (e.g., a white-colored character meaning "green"). We observed contingent attentional capture by the distractor, which was reflected by a deficit in identifying the subsequent target. This result suggests that because of the attentional set, stimuli were scanned on the basis of the target-defining property at an abstract semantic level of representation.     

Object-based attentional selection and awareness of objects

This study examined whether object-based attentional selection depends on the observer's awareness of objects, using objects defined by perceptual completion. As an indicator of object-based attention, we studied the same-object advantage, where observers respond faster to a target within a cued object than within a noncued object. The same-object advantage was not found in the condition where observers were unaware of the objects (inattentional blindness). On the other hand, the same-object advantage was observed in the condition where observers were aware of the objects. These results suggest that the intensity of object representations can be influenced by observers’ awareness of objects, which affects the occurrence of object-based effects. We propose that attention/inattention (or awareness/unawareness) is graded and observers’ awareness of the objects might serve to boost an otherwise noisy/low signal representation for obtaining object-based effects.     

Brief and rare mental “breaks” keep you focused: Deactivation and reactivation of task goals preempt vigilance decrements

We newly propose that the vigilance decrement occurs because the cognitive control system fails to maintain active the goal of the vigilance task over prolonged periods of time (goal habituation). Further, we hypothesized that momentarily deactivating this goal (via a switch in tasks) would prevent the activation level of the vigilance goal from ever habituating. We asked observers to perform a visual vigilance task while maintaining digits in-memory. When observers retrieved the digits at the end of the vigilance task, their vigilance performance steeply declined over time. However, when observers were asked to sporadically recollect the digits during the vigilance task, the vigilance decrement was averted. Our results present a direct challenge to the pervasive view that vigilance decrements are due to a depletion of attentional resources and provide a tractable mechanism to prevent this insidious phenomenon in everyday life.     

Temporal dissociation between category-based and item-based processes in rejecting distractors

Presenting a target-like distractor in an RSVP task deteriorates the detection of a trailing target, because the visual system has difficulties in rejecting the erroneously accepted distractor. We investigated whether the rejection process is influenced by observers’ knowledge regarding possible distractors. Observers identified a letter (target) embedded in a stream of line patterns, rejecting a preceding distractor (digit). We informed the observers about either the category of distractors (“digit”) or the identity of the distractor (e.g., “5”). The distractors with certain distractor–target lags increased identification errors, indicating that the distractor rejection process temporarily interfered with the target identification. When the observers knew the distractor identity, the rejection process started later than when they knew only the distractor category. These results suggest that the rejection process may operate at either the category or the individual-item level; however, the setting of the rejection level is not under the observers’ control.     

Intertrial inhibition of focused attention in pop-out search

When a visual search for a color oddball is performed, responses to target-present trials are affected by the color of items in immediately preceding target-absent trials, a phenomenon known as the distractor-previewing effect (DPE). Specifically, the color of the items in the target-absent trial suppresses responses to a target of that color in the subsequent trial, even though participants report a target feature uncorrelated with color. We believe that this suppression reflects a transient inhibitory effect on focused attention that biases attention away from items that are of the same color as the items in the target-absent trial. Experiments 1-3 show that the DPE is present only in tasks that require focused attention. Experiments 4A and 4B show that the DPE persists even when target-absent displays are masked. Last, Experiment 5 shows that the DPE emerges as early as within the first 100 msec of a target-present trial and is fully in place by the 250-msec mark.     

Attentional awakening: gradual modulation of temporal attention in rapid serial visual presentation

Orienting attention to a point in time facilitates processing of an item within rapidly changing surroundings. We used a one-target RSVP task to look for differences in accuracy in reporting a target related to when the target temporally appeared in the sequence. The results show that observers correctly report a target early in the sequence less frequently than later in the sequence. Previous RSVP studies predicted equivalently accurate performances for one target wherever it appeared in the sequence. We named this new phenomenon attentional awakening, which reflects a gradual modulation of temporal attention in a rapid sequence. This study was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science awarded to Kazuhiko Yokosawa.