The effect of prevalence on distractor speeded search termination

Visual search can be disrupted by irrelevant salient stimuli. Recently, Moher (Psychological Science, 31(1), 31-42, 2020) found salient distractors to speed search when a target was absent and increase error rates when the target was present. That is, distractors lowered search-quitting thresholds. Nonetheless, the salient distractors Moher used were present on 50% of all trials. Since distractor prevalence has been found to influence search processes more broadly, here, we aimed to test the effect of distractor prevalence on this distractor-quitting threshold effect (QTE). To do so, we conducted two experiments. Experiment 1 compared the performance of individuals in a search task where the target was present on 50% of trials across two distractor-prevalence conditions (25% vs. 75% prevalence). Experiment 2 followed the same procedure, except with a wider probability margin (10% vs. 90% prevalence). In Experiment 1, distractor prevalence did not modulate the QTE. Critically, in Experiment 2, the QTE was modulated. For high-prevalence distractors (90%), a QTE was observed. However, as low-prevalence distractors (10%) did not speed search, no QTE was observed. One potential reason no QTE was observed was because low-prevalence distractors have significantly greater attentional capture, which washed out speeded termination effects.

The specificity of feature-based attentional guidance is equivalent under single- and dual-target search

Individuals actively maintain attentional templates to prioritize target-matching inputs. While previous works have established that multiple templates can be held simultaneously, current understanding is limited with respect to the representational quality of such templates. We thus investigated: (a) whether the maintenance of two templates is limited to broad, coarse-grained representations, and if not, (b) whether there is nonetheless a decline in the achievable level of specificity when multiple attentional templates are held simultaneously. Using a spatial cueing procedure, we probed the breadth of attentional templates while participants maintained either one (Experiment 1) or two target colors (Experiment 2) under conditions of low- or high-similarity search and found specific template maintenance during high-similarity search for both single- and dual-target conditions. We then directly compared template specificity during single- and dual-target maintenance in Experiment 3, probing at the point of differentiation between target and nontarget feature values observed during single-target search. Here we found no difference in the selectivity of cue validity effects between single- and dual-target search, suggesting equivalent template specificity regardless of whether one or two features are relevant to search. Lastly, in Experiment 4, we established that such template specificity is dependent on access to visual working memory. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Emphasizing responder speed or accuracy modulates but does not abolish the distractor-induced quitting effect in visual search

When a highly salient distractor is present in a search array, it speeds target absent visual search and increases errors during target present visual search, suggesting lowered quitting thresholds (Moher in Psychol Sci 31(1):31-42, 2020). Missing a critical target in the presence of a highly salient distractor can have dire consequences in real-world search tasks where accurate target detection is crucial, such as baggage screening. As such, the current study examined whether emphasizing either accuracy or speed would eliminate the distractor-generated quitting threshold effect (QTE). Three blocks of a target detection search task which included a highly salient distractor on half of all trials were used. In one block, participants received no instructions or feedback regarding performance. In the remaining two blocks, they received instructions and trial-by-trial feedback that either emphasized response speed or response accuracy. Overall, the distractor lowered quitting thresholds, regardless of whether response speed or response accuracy was emphasized in a block of trials. However, the effect of the distractor on target misses was smaller when accuracy was emphasized. It, therefore, appears that while the distractor QTE is not easily eradicated by explicit instructions and feedback, it can be shifted. As such, future research should examine the applicability of these and similar strategies in real-world search scenarios.

Delayed onsets are not necessary for generating distractor quitting thresholds effects in visual search

Salient distractors lower quitting thresholds in visual search. That is, when searching for the presence of a target among filler items, a large heterogeneously coloured distractor presented at a delayed onset produces quick target-absent judgements and increased target-present errors. The aim of the current study was to explore if the timing of the salient distractor modulates this Quitting Threshold Effect (QTE). In Experiment 1, participants completed a target detection search task in the presence or absence of a salient singleton distractor that either appeared simultaneously with other search items or appeared at a delayed onset (i.e., 100 ms or 250 ms after other array items appeared). In Experiment 2, a similar method was used, except that the salient singleton distractor appeared simultaneously, 100 ms before, or 100 ms after the other array items. Across both experiments, we observed robust distractor QTEs. Regardless of their onset, salient distractors decreased target-absent search speeds and increased target-present error rates. In all, the present findings suggest that delayed onsets are not required for lowered quitting thresholds in visual search.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Eliminating the Low-Prevalence Effect in Visual Search With a Remarkably Simple Strategy

The low-prevalence effect in visual search occurs when rare targets are missed at a disproportionately high rate. This effect has enormous significance for health and public safety and has proven resistant to intervention. In three experiments (Ns = 41, 40, and 44 adults), we documented a dramatic reduction of the effect using a simple cognitive strategy requiring no training. Instead of asking participants to search for the presence or absence of a target, as is typically done in visual search tasks, we asked participants to engage in "similarity search"-to identify the display element most similar to a target on every trial, regardless of whether a target was present. When participants received normal search instructions, we observed strong low-prevalence effects. When participants used similarity search, we failed to detect the low-prevalence effect under identical visual conditions across three experiments.

How is location defined? Implications for learning and transfer of location-specific control

Much research has explored location-specific proportion compatibility (LSPC) effects (i.e., how the appearance of a stimulus in certain locations can reactively trigger different attentional control settings) to elucidate mechanisms underlying reactive control. Recently, however, failures to reproduce key evidence showing transfer of LSPC effects (originally reported in Crump & Milliken, 2009) have called into question whether control per se supports these effects. Notably, Crump and Milliken (2009), and all studies attempting to reproduce their findings, presented stimuli in two locations, one above and one below fixation. Inspired by research on differences between horizontal and vertical meridians, we examined the consequences of defining location in this way compared with alternatives. Experiments 1 and 2 demonstrated that LSPC effects are robust when location is defined as left versus right and larger than when location is defined as upper versus lower, and additionally demonstrated LSPC effects for two locations within the same coarse spatial category (e.g., left vs. farther left). In Experiment 3, we aimed to reproduce Crump and Milliken's key findings using left and right locations for the first time. Critically, we found transfer of the LSPC effect to diagnostic items across two designs and the first evidence for a robust experiment wide LSPC effect for inducer items. Our findings support theories positing that LSPC effects reflect location-specific attentional control and more generally suggest that choosing a definition of location is not a minor methodological decision but critically impacts learning and transfer of location-specific attentional control. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Typicality modulates the visual awareness of objects

In the present study, we assessed whether typicality can influence the visual awareness of objects. Participants tracked moving images of objects and counted how often members of one category bounced off the edges of the display. On the last trial, an unexpected object moved across the display. In our first two experiments, this object could belong to the same category as the tracked or untracked objects. While participants were more likely to notice atypical members of the untracked category, this pattern of results reversed when participants tracked atypical objects. In our last two experiments, the unexpected object could belong to the same category as the tracked objects or a new category of objects. In this case, participants were more likely to notice typical members of both the tracked category and the new category. Together, these findings suggest that typicality can modulate the visual awareness of objects.

EXPRESS: Can arrows change the subjective perception of space? Exploring symbolic attention repulsion

The attention repulsion effect (ARE) refers to distortions in the perception of space for areas nearby the focus of attention. For instance, when attending to the right-hand side of the visual field, objects in central vision may appear as though they are shifted to the left. The phenomenon is likely caused by changes in visual cell functioning. To date, research on the ARE has almost exclusively used exogenous manipulations of attention. In contrast, research exploring endogenous attention repulsion has been mixed, and no research has explored the effects of non-predictive arrow cues on this phenomenon. This gap in the literature is unexpected, as symbolic attention appears to be a unique form of attentional orienting compared to endogenous and exogenous attention. Therefore, the current study explored the effects of symbolic orienting on spatial repulsion and compared it to an exogenously generated ARE. Across four experiments, both exogenous and symbolic orienting resulted in AREs; however, the magnitude of the symbolic ARE was smaller than the exogenous ARE. This difference in magnitude persisted, even after testing both phenomena using stimulus timing parameters known to produce optimal effects in traditional attentional cueing paradigms. Therefore, compared to symbolic attention, it appears that exogenous manipulations may tightly constrict attention resources on the cued location, in turn potentially influencing the functioning of visual cells for enhanced perceptual processing.

The item-specific proportion congruency effect can be contaminated by short-term repetition priming

The item-specific proportion congruency (ISPC) effect reflects the phenomenon that Stroop congruency effects are larger for Stroop items that are more likely to be congruent (MC) than incongruent (MI). While the ISPC effect is purported to reflect long-term memory associations, the proportion manipulation entails that stimulus repetitions vary as a function of the MC and MI conditions, suggesting that a short-term repetition priming process may also contribute. In the present study, we investigated whether the ISPC effect reflected contributions from separate long-term associative learning and short-term repetition priming processes. To do so, the magnitude of the ISPC effect was compared when stimulus repetitions were present and absent. While the ISPC effect was robust, it was revealed that removing stimulus repetitions significantly attenuated the effect. Overall, the present study indicates the ISPC effect can reflect contributions from both short-term repetition and long-term memory processes.

Salience matters: Distractors may, or may not, speed target-absent searches

Attention is often captured by irrelevant but salient changes in the environment, and usually results in slowed search speeds and increased errors during a typical visual search task. Nonetheless, a recent study conducted by Moher (2020, Psychological Science, 31[1], 31-42) found that the effect of a highly salient distractor on visual search depended on whether or not a target was also present in the display. While the distractor slowed search and increased errors for target-present trials, it speeded search for target-absent trials. Here, we aimed to replicate this finding and explore a potential boundary condition to the effect by manipulating the overall salience of the distractor. We did this by changing the size of the distractor to make it more or less salient. In Experiment, participants conducted a target-present and target-absent visual search task in the presence of a large, delayed-onset color distractor similar to that used in Moher's Study. In Experiment 2, a distractor that was much smaller than that used in the original Moher study was utilized. Critically, when a large distractor was used, the original findings of Moher were largely replicated; large salient distractors speeded target-absent visual search and increased errors for target-present visual search. However, when a smaller distractor was used, the results differed. For target-absent trials, search speeds were slower when the distractor was present compared with when it was absent. Thus, it appears that a highly salient distractor might be needed to trigger a shift in visual search strategy, and subsequently, lower quitting thresholds.

Is the attentional SNARC effect truly attentional? Using temporal order judgements to differentiate attention from response

The spatial–numerical association of response codes (SNARC) effect reflects the phenomenon that low digits are responded to faster with the left hand and high digits with the right. Recently, a particular variant of the SNARC effect known as the attentional SNARC (which reflects that attention can be shifted in a similar manner) has had notable replicability issues. However, a potentially useful method for measuring it was revealed by Casarotti et al. using a temporal order judgement (TOJ) task. Accordingly, the present study evaluated whether Casarotti et al.’s results were reproducible by presenting a low (1) or high (9) digit prior to a TOJ task where participants had to indicate which of two peripherally presented targets appeared first (Experiment 1) or second (Experiment 2). In Experiment 1, it was revealed that the findings of Casarotti et al.’s were indeed observable upon replication. In Experiment 2, when attention and response dimensions were put in opposition, the SNARC effect corresponded to the side of response rather than attention. Taken together, the present study confirms the robustness of the attentional SNARC in TOJ tasks, but that it is not likely due to shifts in attention.

Tuning the ensemble: Incidental skewing of the perceptual average through memory-driven selection

The process by which multiple items within an object grouping are rapidly summarized along a given visual dimension into a single mean value (i.e., perceptual averaging) has increasingly been shown to interact dynamically with visual working memory (VWM). Commonly, this interaction is studied with respect to the influence of perceptual averaging over VWM, but it is also the case that VWM can support perceptual averaging. Here, we argue that, in the presence of memory-matching elements, VWM exerts an obligatory influence over perceptual averaging even when it is detrimental to do so. Over four experiments, we tested our hypothesis by having individuals perform a mean orientation estimation task while concurrently maintaining a colored object in VWM. We anticipated that mean orientation reports would be attracted to the local mean of memory-matching items if such items are prioritized in perceptual average judgments. This was indeed the case as we observed a persistent bias in mean orientation judgments toward the subset mean of items matching the VWM item color, despite color being entirely irrelevant to the mean orientation task. Our results thus highlight a goal-invariant influence of VWM over perceptual averaging, which we attribute to amplification through memory-driven selection. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Directed avoidance and its effect on visual working memory

Attentional control processes help to prioritize the storage of information in visual working memory (VWM) by gating what enters the system and influencing how precisely this information is stored. However, the extent to which such prioritization occurs deliberately, opposed to incidentally, is poorly understood. In large part, this is because investigations of this matter have almost exclusively relied on comparisons of memory for exogenously cued items versus uncued items. To understand whether prioritization occurs independent of intention, though, it is essential to examine instances in which attended items are entirely task-irrelevant. Thus, in the current study we used a directed avoidance paradigm to examine VWM performance following the selection of an item known to be task-irrelevant. In Experiment 1, we confirmed that cueing the color of a non-target item paradoxically increases attention to the cued item when the target color is unknown, resulting in longer search times (in line with previous findings). In Experiments 2 and 3, we applied the same cueing procedure to a delayed-estimation task of VWM, but now found a non-target cueing benefit in which the recall of task-relevant items was improved by directed avoidance. We further found that this effect is not solely due to the reprioritization of cognitive resources during maintenance (Exp. 4), but involves additional control processes that 1) reallocate resources to relevant items at encoding, and 2) selectively stabilize such items during the transition from encoding to maintenance (Exp. 5). As such, we suggest that while attentionally selected items may initially be prioritized independent of importance, more controlled mechanisms reallocate resources on the basis of relevance when sufficient time is provided before the sensory information is removed or displaced.

Does feature-based attention play a role in the episodic retrieval of event files?

In stimulus identification tasks, stimulus and response, and location and response information, is thought to become integrated into a common event representation following a response. Evidence for this feature integration comes from paradigms requiring keypress responses to pairs of sequentially presented stimuli. In such paradigms, there is a robust cost when a target event only partially matches the preceding event representation. This is known as the partial repetition cost. Notably, however, these experiments rely on discrimination responses. Recent evidence has suggested that changing the responses to localization or detection responses eliminates partial repetition costs. If changing the response type can eliminate partial repetition costs it becomes necessary to question whether partial repetition costs reflect feature integration or some other mechanism. In the current study, we look to answer this question by using a design that as closely as possible matched typical partial repetition cost experiments in overall stimulus processing and response requirements. Unlike typical experiments where participants make a cued response to a first stimulus before making a discrimination response to a second stimulus, here we reversed that sequence such that participants made a discrimination response to the first stimulus before making a cued response to the second. In Experiment 1, this small change eliminated or substantially reduced the typically large partial repetition costs. In Experiment 2 we returned to the typical sequence and restored the large partial repetition costs. Experiment 3 confirmed these findings, which have implications for interpreting partial repetition costs and for feature integration theories in general. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Is attention really biased toward the last target location in visual search? The role of focal attention and stimulus-response translation rules

There is considerable confusion in the visual attention literature as to whether shifts of attention are biased against or in favor of previously attended regions. Studies requiring target localization have shown a performance cost when the target location randomly repeats instead of changes, whereas studies requiring arbitrary keypress responses to target identities have shown a benefit. These studies differ in the amount of attention required to the target and in the stimulus-response translation rules. To evaluate the contribution of each of these factors in accounting for the mixed results, we had participants indicate whether color singletons appeared in the left versus right visual field, or in the upper versus lower visual field, by making spatially compatible keypress responses (a between-experiment manipulation of the stimulus-response translation rules). Within each experiment, we manipulated whether a subtle discrimination of shape was necessary before localizing the target (a manipulation of focal attention). The findings revealed that the costs and benefits for repeating the target location are determined by stimulus-response translation rules, with no effect of or on attention independent of these rules. The results are accounted for by the theory of event coding, and further challenge the notion that location repetition effects reliably reflect attentional bias. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Examining the Role of Attention and Sensory Stimulation in the Attentional Repulsion Effect

It has been suggested that visual attention warps space, such that stimuli appearing near its locus are perceived as farther away than they actually are. This is known as the attentional repulsion effect (ARE). Recent data challenge the role of attention as the sole factor responsible for the ARE, suggesting instead that the ARE is, at least in part, a product of low level sensory interactions between a peripheral orienting cue and the Vernier target stimulus used to measure the effect. Here, we directly test whether attentional orienting, without a cue in peripheral vision to guide attention, is sufficient for generating an ARE. In Experiment 1, attention was guided to the visual periphery by a central symbolic cue that reliably indicated the locations of to-be-identified targets in peripheral vision. On a subset of trials, we probed for an ARE with Vernier targets. Reaction time (RT) data revealed that the cue guided attention but there was no trace of an ARE. In Experiment 2, we ensured that the Vernier targets were sensitive to the ARE by using the standard spatially uninformative peripheral cue to guide attention instead of the central symbolic cue. RT data again revealed that the cue guided attention, while the Vernier targets revealed an ARE. Collectively, these data suggest that attentional orienting without peripheral sensory stimulation is not sufficient for generating an ARE.

"Two Minds Don't Blink Alike": The Attentional Blink Does Not Occur in a Joint Context

Typically, when two individuals perform a task together, each partner monitors the other partners' responses and goals to ensure that the task is completed efficiently. This monitoring is thought to involve a co-representation of the joint goals and task, as well as a simulation of the partners' performance. Evidence for such "co-representation" of goals and task, and "simulation" of responses has come from numerous visual attention studies in which two participants complete different components of the same task. In the present research, an adaptation of the attentional blink task was used to determine if co-representation could exert an influence over the associated attentional mechanisms. Participants completed a rapid serial visual presentation task in which they first identified a target letter (T1) and then detected the presence of the letter X (T2) presented one to seven letters after T1. In the individual condition, the participant identified T1 and then detected T2. In the joint condition, one participant identified T1 and the other participant detected T2. Across two experiments, an attentional blink (decreased accuracy in detecting T2 when presented three letters after T1) was observed in the individual condition, but not in joint conditions. A joint attentional blink may not emerge because the co-representation mechanisms that enable joint action exert a stronger influence at information processing stages that do not overlap with those that lead to the attentional blink.