Conditions Of High Perceptual Load Research Articles

Influence of Perceptual Load on Attentional Orienting in Post-Stroke Fatigue: A Study of Auditory Evoked Potentials

Objective Increasing perceptual load alters behavioral outcomes in post-stroke fatigue (PSF). While the effect of perceptual load on top-down attentional processing is known, here we investigate if increasing perceptual load modulates bottom-up attentional processing in a fatigue dependent manner. Methods In this cross-sectional observational study, in 29 first-time stroke survivors with no clinical depression, an auditory oddball task consisting of target, standard, and novel tones was performed in conditions of low and high perceptual load. Electroencephalography was used to measure auditory evoked potentials. Perceived effort was rated using the visual analog scale at regular intervals during the experiment. Fatigue was measured using the fatigue severity scale. The effect of fatigue and perceptual load on behavior (response time, accuracy, and effort rating) and auditory evoked potentials (amplitude and latency) was examined using mixed model ananlysis of variances (ANOVA). Results Response time was prolonged with greater perceptual load and fatigue. There was no effect of load or fatigue on accuracy. Greater effort was reported with higher perceptual load both in high and low fatigue. p300a amplitude of auditory evoked potentials (AEP) for novel stimuli was attenuated in high fatigue with increasing load when compared to low fatigue. Latency of p300a was longer in low fatigue with increasing load when compared to high fatigue. There were no effects on p300b components, with smaller N100 in high load conditions. Interpretation High fatigue specific modulation of p300a component of AEP with increasing load is indicative of distractor driven alteration in orienting response, suggestive of compromise in bottom-up selective attention in PSF.

Cue Predictability Modulates the Perceptual Load's Attentional Control on Threatening Facial Distractors

Background: According to the perceptual load theory, distractor processing is determined by the perceptual load. Alternatively, some explanations suggest that perceptual load and distractor salience may have opposing effects. Objectives: Although numerous studies have been conducted on the effect of distractor salience on attentional capture, even under conditions of high perceptual load, it is still unclear whether spatial cueing of the distractor interferes with the perceptual load. Methods: In two experiments, the effect of the predictability of distractor cueing on attentional capture due to threatening facial stimuli was studied using a modified flanker task. In experiment 2, unlike the first experiment, heterogeneous targets and distractors were used to mimic real-life experiences. Results: In experiment 1, the high perceptual load was associated with decreased distractor processing, whether the cueing was completely valid, invalid, or absent. However, the distractor processing between low and high perceptual loads was not different in ambiguous cueing. In the second experiment, contrary to the first experiment, no perceptual load effect was observed in the absence of spatial cueing. Conclusions: Even in displays with high perceptual load, some stimulus-driven features-inability to predict the distractor's location—can interfere with attentional control. Therefore, although the perceptual load is an influential factor in the selection, it clearly cannot be the only factor determining attentional control. Additionally, this study reveals that the effect of perceptual load on attentional control in everyday life should be further studied and questioned.

Effect of Auditory Distractors on Speech Recognition and Listening Effort.

Everyday listening environments are filled with competing noise and distractors. Although significant research has examined the effect of competing noise on speech recognition and listening effort, little is understood about the effect of distraction. The framework for understanding effortful listening recognizes the importance of attention-related processes in speech recognition and listening effort; however, it underspecifies the role that they play, particularly with respect to distraction. The load theory of attention predicts that resources will be automatically allocated to processing a distractor, but only if perceptual load in the listening task is low enough. If perceptual load is high (i.e., listening in noise), then resources that would otherwise be allocated to processing a distractor are used to overcome the increased perceptual load and are unavailable for distractor processing. Although there is ample evidence for this theory in the visual domain, there has been little research investigating how the load theory of attention may apply to speech processing. In this study, we sought to measure the effect of distractors on speech recognition and listening effort and to evaluate whether the load theory of attention can be used to understand a listener's resource allocation in the presence of distractors. Fifteen adult listeners participated in a monosyllabic words repetition task. Test stimuli were presented in quiet or in competing speech (+5 dB signal-to-noise ratio) and in distractor or no distractor conditions. In conditions with distractors, auditory distractors were presented before the target words on 24% of the trials in quiet and in noise. Percent-correct was recorded as speech recognition, and verbal response time (VRT) was recorded as a measure of listening effort. A significant interaction was present for speech recognition, showing reduced speech recognition when distractors were presented in the quiet condition but no effect of distractors when noise was present. VRTs were significantly longer when distractors were present, regardless of listening condition. Consistent with the load theory of attention, distractors significantly reduced speech recognition in the low-perceptual load condition (i.e., listening in quiet) but did not impact speech recognition scores in conditions of high perceptual load (i.e., listening in noise). The increases in VRTs in the presence of distractors in both low- and high-perceptual load conditions (i.e., quiet and noise) suggest that the load theory of attention may not apply to listening effort. However, the large effect of distractors on VRT in both conditions is consistent with the previous work demonstrating that distraction-related shifts of attention can delay processing of the target task. These findings also fit within the framework for understanding effortful listening, which proposes that involuntary attentional shifts result in a depletion of cognitive resources, leaving less resources readily available to process the signal of interest; resulting in increased listening effort (i.e., elongated VRT).

Irrelevant positive emotional information facilitates response inhibition only under a high perceptual load

Response inhibition involves suppressing those responses that are no longer needed. Previous research has separately studied the role of attentional resources and emotional information in response inhibition. Here, we simultaneously manipulate attentional resources and emotional information to investigate the interactive role of emotional information and attentional resources. Attentional resources were manipulated by changing the levels of perceptual load (low and high) of go signals. Emotional information was manipulated by changing the emotional content (irrelevant positive and negative emotional information) of the stop signals. Participants made a go response based on searching for a target letter in conditions of either low perceptual load or high perceptual load. They withheld their response on the presentation of a stop signal. The stop-signal stimulus was selected from two classes: arousal matched positive and negative IAPS images (Experiment 1) and happy, angry, and neutral faces (Experiment 2). The result showed a consistent interaction pattern of perceptual load and emotional information across the two experiments, such that irrelevant positive emotional information consistently improved inhibitory control, albeit only under high load. These results have theoretical implications for understanding the nature of emotional information and their interaction with attentional resources in cognitive control functions.

High bladder pressure reduces the ability to filter out interference from distractors in low perceptual load condition.

According to the load theory of attention, an active cognitive control mechanism is needed to ensure that behaviour is controlled by target-relevant information when distractors are also perceived. Although the active cognitive control mechanism consists of working memory, cognitive flexibility, and inhibition components, predictions regarding the load effects of this mechanism were derived mostly from studies on working memory. We aimed to test whether these predictions are also valid for an inhibition component. The inhibitory load was manipulated physiologically by creating different bladder pressure and its effects on distractor interference were examined under low and high perceptual load conditions. The results indicated that the availability of inhibitory control resources was important for decreasing the interference of distractors in the low perceptual load condition and that the high perceptual load reduced the effects of distractors independently from the availability of inhibitory resources. The results were consistent with the predictions of load theory, and to the best of our knowledge, the study provided the first piece of evidence in terms of the load effect of inhibition component on distractor interference.

Reward history modulates perceptual load effects

The reward history of a stimulus can yield strong attentional selection biases. Indeed, attentional capture can be triggered by previously rewarded items which are neither salient nor relevant for the ongoing task, even when selection is clearly counter-productive to actually obtain the reward outcome. Therefore, value-driven attentional capture (VDAC) has been argued to be an automatic attention mechanism. Our study aimed at putting the VDAC automaticity directly to the test. For this purpose, the Load Theory offers a comprehensive framework where distraction is observed under low but not high perceptual load condition. Nevertheless, if VDAC is indeed automatic, distraction by reward-stimuli should be observed on both perceptual load conditions. We used a feature vs. conjunction discrimination of a go/no-go cue to manipulate perceptual load. As expected, our results revealed that perceptual load decreased interference produced by low-reward distractor. However, this effect was not significant for high-reward distractor, giving support to VDAC automaticity. We discussed our results in light of the Load Theory literature and we strongly encourage to consider reward history along with perceptual load in determining attentional capture.

Nonlinear Effects of Linearly Increasing Perceptual Load on ERPs to Emotional Pictures.

The prioritized processing of emotional as compared to neutral stimuli is reflected in enlarged event-related potentials (ERPs). However, perceptual load theory proposes that under conditions of high perceptual load, information processing is attenuated or abolished. The parametrical effects of load on ERPs to emotional pictures are unknown. To shed light on this question, the current preregistered ERP study (N = 30) systematically investigated the effects of load on ERPs to task-irrelevant negative, neutral, and positive pictures. Crucially, while perceptual input was held constant, perceptual load was systematically manipulated so that it increased linearly across 4 load levels, which was evident in behavioral data. In contrast, load effects on ERP differences between emotional and neutral stimuli did not follow a linear function. For the N1, early posterior negativity and late positive potential, a nonlinear function with reversed emotion effects at the third load level provided the best fit. These findings do not only show that perceptual load attenuates emotional picture processing but also suggest that active processes are initiated to reduce distraction by emotional information. Moreover, these effects of perceptual load on emotional ERP components appear to deviate from theoretically expected functions.

Effects of perceptual load on eyewitness memory are moderated by individual differences in cognitive ability

ABSTRACTPrevious research has identified perceptual load – the amount of perceptual processing required by a scene – as a potentially important factor in eyewitness memory. Here, we investigated whether effects of perceptual load on eyewitness memory for a simulated crime are moderated by individual differences in cognitive ability. We presented participants with a video of a simulated crime that imposed either high or low perceptual load, followed by a written narrative which contained a mixture of neutral and misleading descriptions of critical details. We examined the effects of three cognitive variables (working memory capacity, verbal cognitive ability and analytical reasoning) on participants’ ability to accurately recall details of the video in both the misinformation and control conditions, and to detect a change in the clothing of a main character. General cognitive ability was associated with improved global memory for details of the event, and enhanced change detection under load. Greater WM capacity and a tendency towards analytical reasoning were both associated with resistance to misinformation under conditions of high perceptual load. We conclude that higher levels of cognitive ability, assessed across a number of domains, may enable eyewitnesses to withstand the effects of perceptual load and preserve the accuracy of their memories.

Musical Training Improves Audiovisual Integration Capacity under Conditions of High Perceptual Load.

In considering capacity measures of audiovisual integration, it has become apparent that there is a wide degree of variation both within (based on unimodal and multimodal stimulus characteristics) and between participants. Recent work has discussed performance on a number of cognitive tasks that can form a regression model accounting for nearly a quarter of the variation in audiovisual integration capacity. The current study involves an investigation of whether different elements of musicality in participants can contribute to additional variation in capacity. Participants were presented with a series of rapidly changing visual displays and asked to note which elements of that display changed in synchrony with a tone. Results were fitted to a previously used model to establish capacity estimates, and these estimates were included in correlational analyses with musical training, musical perceptual abilities, and active engagement in music. We found that audiovisual integration capacity was positively correlated with amount of musical training, and that this correlation was statistically significant under the most difficult perceptual conditions. Results are discussed in the context of the boosting of perceptual abilities due to musical training, even under conditions that have been previously found to be overly demanding for participants.

Response interference by central foils is modulated by dimensions of depression and anxiety.

We used a maximum-likelihood-based model selection approach to investigate what aspects of affective traits influence flanker interference in a nonaffective task. A total of 153 undergraduates completed measures of anhedonic depression, anxious arousal, anxious apprehension, and a modified flanker task with two levels of perceptual load. For central foils, the most parsimonious model included load, depression, and anxious arousal. Participants scoring low on the depression and anxious arousal scales exhibited a typical perceptual load effect, with larger interference effects observed under low perceptual load compared with high perceptual load conditions. Increased depression symptoms were associated with a reduced perceptual load effect. However, the load effect reemerged in individuals who scored high on both depression and anxious arousal scales, but to a lesser extent than those scoring low on both. This pattern of results underscores the importance of studying co-occurring affective traits and their interactions in the same sample. For peripherally presented foils, the model that only included load as a factor was more parsimonious than any of the models incorporating affective traits. These findings suggest avenues for future research and highlight the role of diverse affective symptoms on various aspects of nonemotional attentional processing.

The Role of Selective Attention in Cross-modal Interactions between Auditory and Visual Features

Evans and Treisman (2010) showed systematic interactions between audition and vision when participants made speeded classifications in one modality while supposedly ignoring another. We found perceptual facilitation between high pitch and high visual position, high spatial frequency and small size, and interference between high pitch and low position, low spatial frequency and large size, while the converse was the case between low pitch and the same visual features. The present study examined the role of selective attention in these cross-modal interactions. Participants performed speeded classification or search tasks of low or high load while attempting to ignore irrelevant stimuli in a different modality. In both paradigms, congruency between the visual and the irrelevant auditory stimulus had an equal effect in the low and in the high perceptual load conditions. A third experiment tested divided attention, requiring participants to compare stimuli across modalities and respond to the visual-auditory compound. The congruency effect was as large with attention focused on one modality as when it was divided across both. These findings offer converging evidence that cross-modal interactions between corresponding basic features are independent of selective attention.

Pupil size and search performance in low and high perceptual load

The ability to focus on a task while disregarding irrelevant information is an example of selective attention. The perceptual-load hypothesis argues that the occurrence of early or late selection mechanisms is determined by task-relevant perceptual load. Additionally, evidence shows that pupil size serves as proxy of locus coeruleus-norepinephrine (LC-NE) activity, a system associated with cognitive and attentional mediation. Here, we assessed pupil baseline (and pupil dilation) as predictors of load-related early and late selection performance. Participants were asked to search for a target in conditions of high and low perceptual load, while ignoring irrelevant stimuli. The results showed that pupil baseline size, measured prior trial onset, significantly predicted the upcoming search efficiency only in low perceptual load, when—according to the perceptual-load hypothesis—all perceptual information receives attentional resources. In addition, pupil dilation was linked to the time course of perceptual processing and predicted response times in both perceptual load conditions, an association that was enhanced in high load. Thus, this study relates attentional selection mechanisms, as defined by the perceptual-load theory, with pupil-related LC-NE activity. Because pupil baseline predicted attentional performance in low load but not in high load, this suggests that different attentional mechanisms are involved, one in which the LC-NE system plays a key role (low load) and one in which it is less relevant (high load). This suggests that the degree with which LC-NE influences behavioral performance is related to the perceptual load of the task at hand.

Opening the window: Size of the attentional window dominates perceptual load and familiarity in visual selection.

Perceptual load theory (Lavie, 1995) claims that visual selection is determined both by the perceptual demands a display imposes and by the perceptual resources an observer has available for processing. This theory is often tested by examining distractor interference in modified flanker tasks, which separate potential target locations from distractor locations and allow researchers to measure distractor processing. Although this task has provided significant insight into cognitive processing, it may also be an example of how a given task obscures potentially important experimental factors. Specifically, the structure of the target array could encourage observers to adopt a narrow attentional window, which could eliminate distractor interference as significant distractor processing has been shown to occur inside but not outside the attentional window (Belopolsky, Zwaan, Theeuwes, & Kramer, 2007). The present experiments included conditions that allowed the target to vary among the same locations as within a structured target array but varied possible nontarget locations that never overlapped with possible target locations. Whenever nontarget items remained in fixed locations, significant distractor processing occurred due to the observer adopting a wide attentional window even under high perceptual load conditions (Experiment 1). Further evidence showed that familiarity with these locations could not explain the interference (Experiment 2A). However, imposing a ring around the target array, similar to what a circular target array might impose, narrowed the attentional window and eliminated distractor interference (Experiment 2B). Thus, the size of the attentional window is capable of dominating both perceptual load and familiarity in visual selection. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Is there a link between media-multitasking and the executive functions of filtering and response inhibition?

Media-multitasking refers to utilising at least two forms of media simultaneously. This study examined the link between media-multitasking and the inhibitory control executive function. Performance on measures of filtering (flanker task) and inhibitory response control (Go/No-Go task) were compared across heavy media multitaskers (HMM), average media multitaskers (AMM) and light media multitaskers (LMM). For both tasks performance was better under low than high perceptual load conditions. For the flanker task, there was an effect of distractor congruency only for the low perceptual load and no performance differences between the media groups. For the Go/No-Go task, there was a distractor congruency effect for the LMM and HMM for the Go-trials. For the No-Go trials there was no difference between the groups’ performance in the low perceptual load condition. The AMM were more adversely affected by the higher perceptual load than the LMM or HMM particularly when the distractors were incongruent and neutral relative to the targets. These results suggest a link between average levels of media-multitasking and the inhibitory control executive function.

Sleepless night, restless mind: Effects of sleep deprivation on mind wandering.

Sleep deprivation can result in degradation of sustained attention through increased distraction by task-irrelevant exogenous stimuli. However, attentional failures in the sleep-deprived state could also be a result of task-unrelated thoughts (TUTs, or mind wandering). Here, well-rested and sleep-deprived participants performed a visual search task under high and low perceptual load conditions. Thought probes were administered at irregular intervals to gauge the frequency of TUTs and level of meta-awareness of mind wandering. Despite sleep-deprived participants reporting more TUTs, they also reported less awareness of TUTs. Although the frequency of TUTs decreased in the high load condition in well-rested participants, they were equally frequent across low and high perceptual load conditions in sleep-deprived participants. Together, these findings suggest that sleep deprivation can result in a loss of ability to allocate attentional resources according to task demands consistent with diminished executive control. This may have been exacerbated by reduced meta-awareness. (PsycINFO Database Record

Hemispheric asymmetry: Looking for a novel signature of the modulation of spatial attention in multisensory processing

The extent to which attention modulates multisensory processing in a top-down fashion is still a subject of debate among researchers. Typically, cognitive psychologists interested in this question have manipulated the participants’ attention in terms of single/dual tasking or focal/divided attention between sensory modalities. We suggest an alternative approach, one that builds on the extensive older literature highlighting hemispheric asymmetries in the distribution of spatial attention. Specifically, spatial attention in vision, audition, and touch is typically biased preferentially toward the right hemispace, especially under conditions of high perceptual load. We review the evidence demonstrating such an attentional bias toward the right in extinction patients and healthy adults, along with the evidence of such rightward-biased attention in multisensory experimental settings. We then evaluate those studies that have demonstrated either a more pronounced multisensory effect in right than in left hemispace, or else similar effects in the two hemispaces. The results suggest that the influence of rightward-biased attention is more likely to be observed when the crossmodal signals interact at later stages of information processing and under conditions of higher perceptual load—that is, conditions under which attention is perhaps a compulsory enhancer of information processing. We therefore suggest that the spatial asymmetry in attention may provide a useful signature of top-down attentional modulation in multisensory processing.

Distracted by pleasure: Effects of positive versus negative valence on emotional capture under load.

We report 3 experiments examining the effects of positive versus negative valence and perceptual load in determining attention capture by irrelevant emotional distractors. Participants performed a letter search task searching for 1 of 2 target letters (X or N) in conditions of either low perceptual load (circular nontarget letters) or high perceptual load (angular nontarget letters that are similar to the target letters). On 25% of the trials an irrelevant emotional distractor was presented at the display center and participants were instructed to ignore it. The distractor stimulus was either positive or negative and was selected from 3 different classes: IAPS pictures of erotica or mutilated bodies (Experiment 1), happy or angry faces (Experiment 2), and faces associated with gain or loss in a prior value-learning phase involving a betting game (Experiment 3). The results showed a consistent pattern of interaction of load and valence across the 3 experiments. Irrelevant emotional distractors produced interference effects on search reaction time (RT) in conditions of low load, with no difference between negative and positive valence. High perceptual load, however, consistently reduced interference from the negative-valence distractors, but had no effect on the positive-valence distractors. As these results were consistently found across 3 different categories of emotional distractors, they suggest the general conclusion that attentional capture by irrelevant emotional distractors depends on both their valence and the level of perceptual load in the task and highlight the special status of distractors associated with pleasure.

Perceptual Load Induces Inattentional Blindness in Drivers

SummaryPerceptual load theory states that the level of perceptual load in a task predicts the processing of task‐irrelevant information. High perceptual load has been shown to result in increased inattentional blindness; however, there is little evidence that this extends beyond artificial computer‐based tasks to real‐world behavior. In this study, we adapted a typical load‐blindness paradigm for use in a driving simulator. Forty‐two drivers performed a series of gap perception tasks where they judged if their vehicle could fit between two parked vehicles, with the task imposing either low or high perceptual load. Awareness for an unexpected pedestrian or animal at the side of the road was found to be significantly lower in the high perceptual load condition. This study is the first to demonstrate perceptual load effects on awareness in an applied setting and has important implications for road safety and future applied research on the perceptual load model.Copyright © 2016 John Wiley & Sons, Ltd.

Inattentional Deafness: Visual Load Leads to Time-Specific Suppression of Auditory Evoked Responses.

The present work clarifies the neural underpinning of inattentional deafness under high visual load. The findings of near-simultaneous load effects on both visual and auditory evoked responses suggest shared audiovisual processing capacity. Temporary depletion of shared capacity in perceptually demanding visual tasks leads to a momentary reduction in sensory processing of auditory stimuli, resulting in inattentional deafness. The dynamic "push-pull" pattern of load effects on visual and auditory processing furthers our understanding of both the neural mechanisms of attention and of cross-modal effects across visual and auditory processing. These results also offer an explanation for many previous failures to find cross-modal effects in experiments where the visual load effects may not have coincided directly with auditory sensory processing.

The Competitive Influences of Perceptual Load and Working Memory Guidance on Selective Attention.

The perceptual load theory in selective attention literature proposes that the interference from task-irrelevant distractor is eliminated when perceptual capacity is fully consumed by task-relevant information. However, the biased competition model suggests that the contents of working memory (WM) can guide attentional selection automatically, even when this guidance is detrimental to visual search. An intriguing but unsolved question is what will happen when selective attention is influenced by both perceptual load and WM guidance. To study this issue, behavioral performances and event-related potentials (ERPs) were recorded when participants were presented with a cue to either identify or hold in memory and had to perform a visual search task subsequently, under conditions of low or high perceptual load. Behavioural data showed that high perceptual load eliminated the attentional capture by WM. The ERP results revealed an obvious WM guidance effect in P1 component with invalid trials eliciting larger P1 than neutral trials, regardless of the level of perceptual load. The interaction between perceptual load and WM guidance was significant for the posterior N1 component. The memory guidance effect on N1 was eliminated by high perceptual load. Standardized Low Resolution Electrical Tomography Analysis (sLORETA) showed that the WM guidance effect and the perceptual load effect on attention can be localized into the occipital area and parietal lobe, respectively. Merely identifying the cue produced no effect on the P1 or N1 component. These results suggest that in selective attention, the information held in WM could capture attention at the early stage of visual processing in the occipital cortex. Interestingly, this initial capture of attention by WM could be modulated by the level of perceptual load and the parietal lobe mediates target selection at the discrimination stage.