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Peripheral vision can be severely impaired by nearby clutter. Decades of research using sparse displays have established that this phenomenon, known as visual crowding, follows Bouma's rule: Interference occurs for target-distractor separations up to half the target's eccentricity. Although considered a fundamental constraint on human vision, it is unclear whether Bouma's rule holds in dense heterogeneous visual environments. Using a genetic algorithm we investigated crowding in densely cluttered displays. Participants were instructed to identify the orientation of a target line (6° eccentricity) among 284 distractor lines. Displays supporting highest accuracy were selected ("survival of the fittest") and combined to create new displays. Performance improved over generations, predominantly driven by the emergence of horizontal flankers within 1° of the near-vertical target, but with no evidence of interference beyond this radius. We conclude that Bouma's rule does not necessarily hold in densely cluttered displays. Instead, a nearest-neighbor segmentation rule provides a better account. [ABSTRACT FROM AUTHOR]

Visual attention serves to select salient and relevant events from the visual input. Selective attention to a visual event can be driven by a synchronous sound. Interestingly, recent evidence suggests that a sound can only drive selection of 1 concurrent visual event, suggesting that attentional capacity is much lower for audiovisual events than for purely visual events. Here we corroborate and extend this finding using a mixture modeling technique that distinguishes between the probability and precision of perception. Observers were presented with displays of multiple continuously flickering objects, of which either 1 or 2 were coupled to a single sound. In 2 experiments, we found that the probability of correctly reporting an object was almost halved when the number of synchronized visual objects increased from 1 to 2. Precision, however, was not affected. This indicates that rather than attention being distributed across multiple simultaneous audiovisual events, just 1 of them is singled out for attentional selection. This was not due to a capacity limit for selecting the visual objects per se; pure visual cues elicited a much higher probability of report and in that case there were clear declines in precision at larger set sizes, indicating the concurrent selection of multiple items. The results point toward a dissociation in capacity for visually and aurally cued prioritization of visual objects. [ABSTRACT FROM AUTHOR]

Although many of our perceptual biases stem from long-term, repeated exposure, current theories of visual search assume a central role for visual working memory (VWM) in guiding attention to target information. Crucially, whether a VWM representation guides attention depends on the relative priority that the memory has within VWM. Here, in a combined visual search/VWM task, we used attentional guidance by irrelevant memories to measure how long a target representation remains prioritized in VWM when observers repeatedly search for the same target. Irrelevant memories started guiding attention already when the target was repeated once, indicating that the target representation rapidly lost priority within VWM as it moved to long-term memory. By showing that training can lead to interference from irrelevant memories, the findings resolve a long-standing paradox on why VWM appears central to, yet at the same time not sufficient nor necessary for attentional guidance. [ABSTRACT FROM AUTHOR]

Visual short-term memory (VSTM) performance is enhanced when the to-be-tested item is cued after encoding. This so-called retro-cue benefit is typically accompanied by a cost for the noncued items, suggesting that information is lost from VSTM upon presentation of a retrospective cue. Here we assessed whether noncued items can be restored to VSTM when made relevant again by a subsequent second cue. We presented either 1 or 2 consecutive retro-cues (80% valid) during the retention interval of a change-detection task. Relative to no cue, a valid cue increased VSTM capacity by 2 items, while an invalid cue decreased capacity by 2. Importantly, when a second, valid cue followed an invalid cue, capacity regained 2 items, so that performance was back on par. In addition, when the second cue was also invalid, there was no extra loss of information from VSTM, suggesting that those items that survived a first invalid cue, automatically also survived a second. We conclude that these results are in support of a very versatile VSTM system, in which memoranda adopt different representational states depending on whether they are deemed relevant now, in the future, or not at all. We discuss a neural model that is consistent with this conclusion. [ABSTRACT FROM AUTHOR]

For stable perception, we maintain mental representations of objects across space and time. What information is linked to such a representation? In this study, we extended our work showing that the spatiotemporal history of an object affects the way the object is attended the next time it is encountered. Observers conducted a visual search for a target among multiple distractors. Either the target location (Experiment 1) or the target feature (Experiment 2) could repeat from trial to trial. The entire visual search display was part of an object that could move in and out of view. Search was speeded when the target property repeated, but especially when the motion trajectory suggested that the same object had emerged. We show that this same-object benefit is tied to both the features and the spatial location of the target. It is most prominent for task-relevant features, but is weak to absent for task-irrelevant target features or for distractors carrying a salient feature. We conclude that attention uses an object-specific memory for relevant target information. Finally, we show that this object-specific memory is not affected by a change in the exterior appearance of the object, but depends on the spatiotemporal history (Experiment 3). [ABSTRACT FROM AUTHOR]

The law of prior entry states that attended objects come to consciousness more quickly than unattended ones. This has been well established in spatial cueing paradigms, where two task-relevant stimuli are presented near-simultaneously at two different locations. Here, we suggest that prior entry also plays a pivotal role in temporal attention paradigms, where stimuli appear at the same location but at distinct moments in time, in rapid serial presentation (RSVP). Specifically, we hypothesize that prior entry can explain temporal order reversals in reporting two targets from RSVP. In support of this, three experiments show that cueing attention toward either of the targets has a strong influence on order errors. We conclude that prior entry provides a viable explanation of the way in which relevant information is prioritized in RSVP. [ABSTRACT FROM AUTHOR]

The attentional blink is the marked deficit in awareness of a 2nd target (T2) when it is presented shortly after the 1st target (T1) in a stream of distractors. When the distractors between T1 and T2 are replaced by even more targets, the attentional blink is reduced or absent, indicating that the attentional blink results from online selection mechanisms that act in response to distracting input rather than being the result of T1-induced cognitive resource depletion. However, Dell'Acqua, Jolicoeur, Luria, and Pluchino (2009) recently contended that an attentional blink is found in the multiple-target case as long as the appropriate trial context and analyses are used, thus reinstating resource-based explanations of the attentional blink and challenging the selection account. Specifically, an attentional blink reemerges when target performance is analyzed contingent on previous target accuracy. We argue on theoretical and empirical grounds that neither the trial context nor the type of analysis poses h serious problem for selection accounts. We show that the attentional blink and previous target contingency effects can be dissociated, with the latter depending more on low-level, short-range competition. We conclude that selection mechanisms involved in filtering for targets still provide a strong and coherent explanation of the attentional blink. [ABSTRACT FROM AUTHOR]

An important question is whether visual attention (the ability to select relevant visual information) and visual working memory (the ability to retain relevant visual information) share the same content representations. Some past research has indicated that they do: Singleton distractors interfered more strongly with a visual search task when they were identical or related to the object held in memory. However, other research has failed to find such effects despite using very similar procedures. The present study, using the same combined working memory and attentional capture paradigm, demonstrates which factors do (varied mapping, low stimulus energy) and which factors do not (exact type of visual memory method used, difficult nature of search, heterogeneity of displays, and instruction) contribute to this discrepancy. [ABSTRACT FROM AUTHOR]

Searching for an object within a cluttered, continuously changing environment can be a very time-consuming process. The authors show that a simple auditory pip drastically decreases search times for a synchronized visual object that is normally very difficult to find. This effect occurs even though the pip contains no information on the location or identity of the visual object. The experiments also show that the effect is not due to general alerting (because it does not occur with visual cues), nor is it due to top-down cuing of the visual change (because it still occurs when the pip is synchronized with distractors on the majority of trials). Instead, we propose that the temporal information of the auditory signal is integrated with the visual signal, generating a relatively salient emergent feature that automatically draws attention. Phenomenally, the synchronous pip makes the visual object pop out from its complex environment, providing a direct demonstration of spatially nonspecific sounds affecting competition in spatial visual processing. [ABSTRACT FROM AUTHOR]

What is the time course of visual attention? Attentional blink studies have found that the 2nd of 2 targets is often missed when presented within about 500 ms from the 1st target, resulting in theories about relatively long-lasting capacity limitations or bottlenecks. Earlier studies, however, reported quite the opposite finding: Attention is transiently enhanced, rather than reduced, for several hundreds of milliseconds after a relevant event. The authors present a general theory, as well as a working computational model, that integrate these findings. There is no central role for capacity limitations or bottlenecks. Central is a rapidly responding gating system (or attentional filter) that seeks to enhance relevant and suppress irrelevant information. When items sufficiently match the target description, they elicit transient excitatory feedback activity (a "boost" function), meant to provide access to working memory. However, in the attentional blink task, the distractor after the target is accidentally boosted, resulting in subsequent strong inhibitory feedback response (a "bounce"), which, in effect, closes the gate to working memory. The theory explains many findings that are problematic for limited-capacity accounts, including a new experiment showing that the attentional blink can be postponed. [ABSTRACT FROM AUTHOR]

In 7 experiments, the authors explored whether visual attention (the ability to select relevant visual information) and visual working memory (the ability to retain relevant visual information) share the same content representations. The presence of singleton distractors interfered more strongly with a visual search task when it was accompanied by an additional memory task. Singleton distractors interfered even more when they were identical or related to the object held in memory, but only when it was difficult to verbalize the memory content. Furthermore, this content-specific interaction occurred for features that were relevant to the memory task but not for irrelevant features of the same object or for once-remembered objects that could be forgotten. Finally, memory-related distractors attracted more eye movements but did not result in longer fixations. The results demonstrate memory-driven attentional capture on the basis of content-specific representations. [ABSTRACT FROM AUTHOR]

The attentional blink refers to the finding that the 2nd of 2 targets embedded in a stream of rapidly presented distractors is often missed. Whereas most theories of the attentional blink focus on limited-capacity processes that occur after target selection, the present work investigates the selection process itself. Identifying a target letter caused an attentional blink for the enumeration of subsequent dot patterns, but this blink was reduced when the dots shared their color with the target letter. In contrast, performance worsened when the color of the dots matched that of the remaining distractors in the stream. Similarity between the targets also affected competition between different sets of dots presented simultaneously within a single display. The authors conclude that the selection of targets from a rapid serial visual presentation stream is mediated by both excitatory and inhibitory attentional control mechanisms. [ABSTRACT FROM AUTHOR]

The attentional blink reflects the impaired ability to identify the 2nd of 2 targets presented in close succession—a phenomenon that is generally thought to reflect a fundamental cognitive limitation. However, the fundamental nature of this impairment has recently been called into question by the counterintuitive finding that task-irrelevant mental activity improves attentional blink performance (C. N. L. Olivers & S. Nieuwenhuis, 2005). The present study found a reduced attentional blink when participants concurrently performed an additional memory task, viewed pictures of positive affective content, or were instructed to focus less on the task. These findings support the hypothesis that the attentional blink is due to an overinvestment of attentional resources in stimulus processing, a suboptimal processing mode that can be counteracted by manipulations promoting divided attention. [ABSTRACT FROM AUTHOR]

Intuitively, dynamic visual stimuli, such as moving objects or flashing lights, attract attention. Visual search tasks have revealed that dynamic targets among static distractors can indeed efficiently guide attention. The present study shows that the reverse case, a static target among dynamic distractors, allows for relatively efficient selection in certain but not all cases. A static target was relatively efficiently found among distractors that featured apparent motion, corroborating earlier findings. The important new finding was that static targets were equally easily found among distractors that blinked on and off continuously, even when each individual item blinked at a random rate. However, search for a static target was less efficient when distractors abruptly varied in luminance but did not completely disappear. The authors suggest that the division into the parvocellular pathway dealing with static visual information, on the one hand, and the magnocellular pathway common to motion and new object onset detection, on the other hand, allows for efficient filtering of dynamic and static information. [ABSTRACT FROM AUTHOR]

The mechanisms underlying segmentation and selection of visual stimuli over time were investigated in patients with posterior parietal damage. In a modified visual search task, a preview of old objects preceded search of a new set for a target while the old items remained. In Experiment 1, control participants ignored old and prioritized new items, but patients had severe difficulties finding the target (especially on the contralesional side). In Experiment 2, simplified displays yielded analogous results, ruling out search ease as a crucial factor in poor preview search. In Experiment 3, outlines around distractor groups (to aid segmentation) improved conjunction but not preview search, suggesting a specific deficit in spatiotemporal segmentation. Experiment 4 ruled out spatial disengagement problems as a factor. The data emphasize the role of spatiotemporal segmentation cues in preview search and the parietal lobe in the role of these cues to prioritize search of new stimuli. [ABSTRACT FROM AUTHOR]

The detection or discrimination of the second of 2 targets in a rapid serial visual presentation (RSVP) task is often temporarily impaired-a phenomenon termed the attentional blink. This study demonstrated that the attentional blink also affects localization performance. Spatial cues pointed out the possible target positions in a subsequent visual search display. When cues were presented inside an attentional blink (as induced by an RSVP task), the observers' capacity to use them was reduced. This effect was not due to attention being highly focused, to general task switching costs, or to complete unawareness of the cues. Instead, the blink induced a systematic localization bias toward the fovea, reflecting what appears to be spatial compression. [ABSTRACT FROM AUTHOR]

P. A. van der Helm and E. L. J. Leeuwenberg (1996) outlined a holographic account of figural goodness of a perceptual stimulus. The theory is mathematically precise and can be applied to a broad spectrum of empirical data. The authors argue, however, that the account is inadequate on both theoretical and empirical grounds. The theoretical difficulties concern the internal consistency of the account and its reliance on unspecified auxiliary assumptions. The account also makes counterintuitive empirical predictions, which do not fit past data or the results of a series of new experimental studies. [ABSTRACT FROM AUTHOR]

Evidence that salient feature singletons guide attention only when the target and the singleton frequently coincide has been taken to suggest that selection of singletons is under top-down control: Observers strategically use an attentional set sensitive to the singleton being a target. Changing the singleton-target (or singleton-distractor) coincidence also changes the opportunity for facilitative and disruptive intertrial effects to occur. The authors show that benefits and costs associated with certain singletons depend at least partly on the preceding trial type. Results are in line with dimensional weighting and perceptual priming accounts, which propose a (semi-) automatic transfer of dimensional activity from one trial to the next. Results also indicate that priming is set independently for each dimension. [ABSTRACT FROM AUTHOR]

Investigates the attentional resources necessary for visual marking using attentional blink. Detection of probe dots on blinked distractors; Accounts on the inhibitory processes involved on visual marking; Amount of attentional resources available for visual marking.

Evidence shows that visual working memory (VWM) is strongly served by attentional mechanisms, whereas other evidence shows that VWM representations readily survive when attention is being taken away. To reconcile these findings, we tested the hypothesis that directing attention away makes a memory representation vulnerable to interference from the test pattern, but only temporarily so. When given sufficient time, the robustness of VWM can be restored so that it is protected against test interference. In 5 experiments, participants remembered a single grating for a later memory test. In the crucial conditions, participants also performed a letter change detection task in between, during the delay period. Experiments 1-3 demonstrate and replicate the predicted effect: The intervening task had an adverse effect on memory performance, but only when the test display appeared immediately after the secondary task. At longer delays of 3.5 s, memory performance was on a par with conditions in which there was no intervening task. By varying the similarity of the test pattern to the memorized pattern, Experiments 4 and 5 further showed that performance suffered at early test intervals, unless the test item was dissimilar to the memory item. The results provide positive evidence for test interference, and demonstrates that the susceptibility to interference only occurs temporarily, as memory is restored when attention is allowed to return to the memorandum. [ABSTRACT FROM AUTHOR]

Humans continuously scan their visual environment for relevant information. Such visual search behavior has typically been studied with tasks in which the search goal is constant and well-defined, requiring relatively little interplay between memory and orienting. Here we studied a situation in which the target is not known in advance, and instead, memory needs to be dynamically updated during the actual search. Observers compared two simultaneously presented arrays of objects for any matching pair of items--a task that requires continuous comparisons between what is seen now and what was seen a few moments ago. To manipulate the balance between memorizing and scanning, we ran two versions of the task. In an eye-tracking version, the objects were continuously available and could be scanned with relative ease. The results suggested that observers preferred scanning over memorizing. In a mouse-tracking version, perceptual availability was limited, and scanning was slowed. Now observers substantially increased their memory use. Thus, the results revealed a flexible and dynamic interplay between memory and perception. The findings aid in further bridging the research fields of attention and memory. [ABSTRACT FROM AUTHOR]

The pupillary light response has been shown not to be a purely reflexive mechanism but to be sensitive to higher order perceptual processes, such as covert visual attention. In the present study we examined whether the pupillary light response is modulated by stimuli that are not physically present but are maintained in visual working memory. In all conditions, displays contained both bright and dark stimuli. Participants were instructed to covertly attend and encode either the bright or the dark stimuli, which then had to be maintained in visual working memory for a subsequent change-detection task. The pupil was smaller in response to encoding bright stimuli compared to dark stimuli. However, this effect did not sustain during the maintenance phase. This was the case even when brightness was directly relevant for the working memory task. These results reveal that the encoding of task-relevant and physically present information in visual working memory is reflected in the pupil. In contrast, the pupil is not sensitive to the maintenance of task-relevant but no longer visible stimuli. One interpretation of our results is that the pupil optimizes its size for perception of stimuli during encoding; however, once stimuli are no longer visible (during maintenance), an "optimal" pupil size no longer serves a purpose, and the pupil may therefore cease to reflect the brightness of the memorized stimuli. [ABSTRACT FROM AUTHOR]

An important question is, to what extent is visual attention driven by the semantics of individual objects, rather than by their visual appearance? This study investigates the hypothesis that timing is a crucial factor in the occurrence and strength of semantic influences on visual orienting. To assess the dynamics of such influences, the authors presented the target instruction either before or after visual stimulus onset, while eye movements were continuously recorded throughout the search. The results show a substantial but delayed bias in orienting toward semantically related objects compared with visually related objects when target instruction is presented before visual stimulus onset. However, this delay can be completely undone by presenting the visual information before the target instruction (Experiment 1). Moreover, the absence or presence of visual competition does not change the temporal dynamics of the semantic bias (Experiment 2). Visual orienting is thus driven by priority settings that dynamically shift between visual and semantic representations, with each of these types of bias operating largely independently. The findings bridge the divide between the visual attention and the psycholinguistic literature. [ABSTRACT FROM AUTHOR]

Recent studies have revealed that the deployment of attention can be biased by the content of visual working memory (VWM), but that stored memories do not always interact with attention. This has led to a model which proposes a division within VWM between a single active template that interacts with perception and multiple accessory representations that do not. The present study was designed to study whether multiple memory representations are able to bias attention. Participants performed a visual search task while maintaining a variable number of colors in VWM. Consistent with earlier findings, we observed increased attentional capture by memory related distractors when VWM was filled with a single item. However, memory related capture was no longer present for memory loads beyond a single item. The absence of memory related capture at higher VWM loads was independent of individual VWM capacity, nor was it attributable to weaker encoding, forgetting, or reduced precision of memory representations. When analyses were limited to those trials in which participants had a relatively precise memory, there was still no sign of attentional guidance at higher loads. However, when observers were cued toward a specific memory item after encoding, interference with search returned. These results are consistent with a distinction within VWM between representations that interact with perception and those that do not, and show that only a single VWM representation at a time can interact with visual attention. [ABSTRACT FROM AUTHOR]

We are constantly extracting regularities from the visual environment to optimize attentional orienting. Here we examine the phenomenon that recurrent presentation of distractors in a specific location leads to its attentional suppression. Specifically, we address the question whether suppression is specific to the spatial regularities of distractors or also extends to visual features bearing statistical regularities. To that end, we used a visual search task with two high-probability locations, each showing one of two distractor types more often than the other. At these high-probability locations, target processing was impaired and attentional capture by either distractor was reduced, consistent with feature-unspecific spatial suppression. However, suppression was more facilitated when the distractor feature was presented at the high-probability location that matched its features, suggesting feature-specific suppression. Interestingly, feature-unspecific spatial suppression only spread between locations when distractors varied within a feature dimension (e.g., red and green) but not when they varied across feature dimensions (e.g., red and square). Our findings thus demonstrate a joint influence of implicitly learned spatial and feature regularities on attention and reveal how the visual system can benefit from complex statistical regularities. When we search the environment for relevant information, we are constantly trying to ignore irrelevant objects to avoid wasting cognitive resources when attempting to overcome distraction by them. To facilitate ignoring these distractors, we can learn to make use of the regularities they exhibit. Much of the research so far has focused on distractor regularities in space, showing that we can effectively suppress locations where distractors are likely to appear. Here, we investigated whether we also learn to use regularities in the visual features of distractors, such as their color or shape, to more easily ignore them. We found that efficient distractor suppression is based on implicit learning about regularities in both the visual features and the spatial position of distractors. Our results thus demonstrate that the visual systems can make use of complex regularities to optimize the distribution of cognitive resources. [ABSTRACT FROM AUTHOR]

Recent empirical and theoretical work suggests that visual features such as color and orientation can be stored or retrieved independently in visual working memory (VWM), even in cases when they belong to the same object. Yet it remains unclear whether different feature dimensions have their own capacity limits, or whether they compete for shared but limited resources in VWM. In 3 experiments, participants memorized arrays of dual-feature objects, for which the number of feature values was fixed on one feature dimension and was varied on the other feature dimension. The results show that memory performance on the fixed dimension was not affected by the number of to-be-stored feature values on the other. These findings provide converging evidence that visual features can be encoded and stored separately in VWM if the task requires it, with each having its own capacity limit and little cross-dimensional interference. [ABSTRACT FROM AUTHOR]

It is generally agreed that attention can be captured in a stimulus-driven or in a goal-driven fashion. In studies that investigated both types of capture, the effects on mean manual response time (reaction time [RT]) are generally additive, suggesting two independent underlying processes. However, potential interactions between the two types of capture may fail to be expressed in manual RT, as it likely reflects multiple processing steps. Here we measured saccadic eye movements along with manual responses. Participants searched a target display for a red letter. To assess contingent capture, this display was preceded by an irrelevant red cue. To assess stimulus-driven capture, the target display could be accompanied by the simultaneous onset of an irrelevant new object. At the level of eye movements, the results showed strong interactions between cue validity and onset presence on the spatiotemporal trajectories of the saccades. However, at the level of manual responses, these effects cancelled out, leading to additive effects on mean RT. We conclude that both types of capture influence a shared spatial orienting mechanism and we provide a descriptive computational model of their dynamics. [ABSTRACT FROM AUTHOR]

Findings from recent studies indicate that planning an action toward an object strengthens its visual working memory (VWM) representation, emphasizing the importance of sensorimotor links in VWM. In the present study, we investigated to what extent such sensorimotor links are modulated by how well-defined an action plan is. In three eye-tracking experiments, we asked participants to memorize a visual stimulus for a subsequent memory test, whereby they performed a specific hand movement toward memory-matching probes. We manipulated action uncertainty so that in the defined action condition, participants knew before the memory delay what specific action they would have to perform at the memory test, while in the undefined action condition, they were informed about the specific action on the object in VWM only after the delay. Importantly, during the delay, participants were presented with a visual detection task, designed to measure any attentional biases toward the memorized object. Across the three experiments, we found moderate evidence that knowing in advance how to act on an object prioritized its mnemonic representation, as expressed in an increased attentional bias toward it. Our results support the idea that knowing what action to perform on an object strengthens its representation in VWM, and further highlight the importance of considering action in the study of VWM. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Recent empirical and theoretical work suggests that visual features such as color and orientation can be stored or retrieved independently in visual working memory (VWM), even in cases when they belong to the same object. Yet it remains unclear whether different feature dimensions have their own capacity limits, or whether they compete for shared but limited resources in VWM. In 3 experiments, participants memorized arrays of dual-feature objects, for which the number of feature values was fixed on one feature dimension and was varied on the other feature dimension. The results show that memory performance on the fixed dimension was not affected by the number of to-be-stored feature values on the other. These findings provide converging evidence that visual features can be encoded and stored separately in VWM if the task requires it, with each having its own capacity limit and little cross-dimensional interference. (PsycINFO Database Record, ((c) 2017 APA, all rights reserved).)