Capturing spatial attention with multisensory cues

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.

IntroductionSelective attention is a crucial mechanism that enables humans to navigate complex environments and accomplish targeted tasks, garnering significant interest from researchers. Numerous studies have found that selective attention can be influenced by emotions; however, previous research has primarily focused on the effects of valence and arousal, neglecting the role of motivation, another dimension of emotion. Additionally, it remains unclear whether emotional motivation’s influence on selective attention differs across various levels of perceptual load.MethodsThis study employed a modified perceptual load Flanker task, using behavioral measures and event-related potentials (ERPs) technique to investigate how the intensity of approach-motivated positive affect influences selective attention under different levels of perceptual load. In each trial, participants were first shown pictures of food or scenes to induce high or low approach-motivated positive affect, followed by a modified perceptual load Flanker task where a searchable array of letters was arranged in a virtual circle around a central fixation point, with an interference letter presented on either the left or right periphery. The searchable array included one target letter and either five identical (low perceptual load) or different irrelevant letters (high perceptual load). Participants were required to identify the target letter and respond with a button press.ResultsThe findings revealed that under conditions of high perceptual load, participants with low approach-motivated positive affect exhibited slower reaction times than those with high approach-motivated positive affect. Meanwhile, the ERP results indicated that under high perceptual load, low approach-motivated positive affect induced a greater N1 in the parieto-occipital region compared to high approach-motivated positive affect. Additionally, high approach-motivated positive affect evoked a greater N2 in the frontal region and a smaller P3 in the parietal region compared to low approach-motivated positive affect and neutral affect.DiscussionThese results demonstrate the inhibitory effect of low approach-motivated positive affect and the enhancing effect of high approach-motivated positive affect on performance in the high perceptual load Flanker task.

Perceptual load, voluntary attention, and aging: An event-related potential study

When and where perceptual load interacts with voluntary visuospatial attention: An event-related potential and dipole modeling study

In two experiments, we investigated the hypothesis of Rowland and Shanks (2006a) that sequence learning of relevant information is resistant to variations in perceptual load. Under conditions of increased selection difficulty, participants incidentally learned a sequence of targets presented together with three distractors. Target and distractors were composed of pairs of letters and shared more or less features with each other, rendering perceptual identification of the target either more (high load) or less (low load) attention demanding. The expression of sequence learning improved significantly under high load conditions as compared to low load conditions. This could indicate that the cognitive system promotes the development of response-based sequence learning in order to cope with the attentional demands arising from high perceptual load. However, the learning process proved to be unaffected by perceptual load when tested under baseline conditions without distractors (Experiment 1) or under opposite load conditions as during training (Experiment 2). This demonstrates that sequence learning is not influenced by increasing selection demands and suggests that sequence learning runs independently of input attention.

EDITORIAL article Front. Psychol., 20 March 2014Sec. Cognition Volume 5 - 2014 | https://doi.org/10.3389/fpsyg.2014.00248

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.

Inattentional blindness describes the failure to detect an unexpected but clearly visible object when our attention is engaged elsewhere. While the factors that determine the occurrence of inattentional blindness are already well understood, there is still a lot to learn about whether and how we process unexpected objects that go unnoticed. Only recently it was shown that although not consciously aware, characteristics of these stimuli can interfere with a primary task: Classification of to-be-attended stimuli was slower when the content of the task-irrelevant, undetected stimulus contradicted that of the attended, to-be-judged stimuli. According to Lavie’s perceptual load model, irrelevant stimuli are likely to reach awareness under conditions of low perceptual load, while they remain undetected under high load, as attentional resources are restricted to the content of focused attention. In the present study, we investigated the applicability of Lavie’s predictions for the processing of stimuli that remain unconscious due to inattentional blindness. In two experiments, we replicated that unconsciously processed stimuli can interfere with intended responses. Also, our manipulation of perceptual load did have an effect on primary task performance. However, against our hypothesis, these effects did not interact with each other. Thus, our results suggest that high perceptual load cannot prevent task-irrelevant stimuli that remain undetected from being processed to an extent that enables them to affect performance in a primary task.

Perceptual load is not always a crucial determinant of early versus late selection

Previous research has investigated whether visual salience (i.e., how much an item stands out) or perceptual load (i.e., display complexity) is the dominant factor in visual selective attention. The evidence has been mixed, with some findings supporting a dominant role for visual salience and some findings supporting a dominant role for perceptual load. However, the complex displays used to impose high perceptual load also introduce a third factor that has gone understudied until recently: the interplay between identity dilution and exposure duration. Adding display items to increase perceptual load dilutes a distractor's identity, which could decrease interference, but the task generally takes longer, which could increase distractor interference. To clarify how these factors interact, the present study used converging measures of distractor interference—both compatibility and singleton presence—to disambiguate effects due to salience, perceptual load, and identity dilution/exposure duration. Compatibility effects support perceptual load as the dominant factor, whereas singleton presence effects do not (Experiment 1). Consistent with salience-based mechanisms, significant distractor processing (both compatibility and presence effects) occurred under high perceptual load when singleton present trials preceded singleton absent trials (Experiment 2A). However, consistent with load-based mechanisms, non-significant compatibility effects occurred under high perceptual load when singleton absent trials preceded singleton present trials (Experiment 2B). Thus, the competition between salience-based and load-based mechanisms depended on the amount of prior experience with singleton present vs. absent displays, which in turn depended on the use of broad vs. narrow attentional allocation strategies. These experience-dependent effects provide further evidence that attention allocation strategies are contingent on factors such as task context and experience.

The perceptual load theory of attention posits that attentional selection occurs early in processing when a task is perceptually demanding but occurs late in processing otherwise. We used a frequency-tagged steady-state evoked potential paradigm to investigate the modality specificity of perceptual load-induced distractor filtering and the nature of neural-competitive interactions between task and distractor stimuli. EEG data were recorded while participants monitored a stream of stimuli occurring in rapid serial visual presentation (RSVP) for the appearance of previously assigned targets. Perceptual load was manipulated by assigning targets that were identifiable by color alone (low load) or by the conjunction of color and orientation (high load). The RSVP task was performed alone and in the presence of task-irrelevant visual and auditory distractors. The RSVP stimuli, visual distractors, and auditory distractors were "tagged" by modulating each at a unique frequency (2.5, 8.5, and 40.0 Hz, respectively), which allowed each to be analyzed separately in the frequency domain. We report three important findings regarding the neural mechanisms of perceptual load. First, we replicated previous findings of within-modality distractor filtering and demonstrated a reduction in visual distractor signals with high perceptual load. Second, auditory steady-state distractor signals were unaffected by manipulations of visual perceptual load, consistent with the idea that perceptual load-induced distractor filtering is modality specific. Third, analysis of task-related signals revealed that visual distractors competed with task stimuli for representation and that increased perceptual load appeared to resolve this competition in favor of the task stimulus.

Application of methanol and optimization of mixture design over the full operating map in an intelligent charge compression ignition (ICCI) engine

Central perceptual load does not reduce ipsilesional flanker interference in parietal extinction.

Effects of emotional intensity under perceptual load: An event-related potentials (ERPs) study

The inability to perceive a visible but unexpected stimulus is a phenomenon studied in cognitive psychology under the name of inattentional blindness (IB). IB reflects the limited capacity of human attention, as a demanding task may leave few, if any, attentional resources available for an unexpected yet visible stimulus to capture attention. The main cognitive mechanism involved is selective attention, which allows individuals to prioritize information relevant to the task at hand while filtering out irrelevant elements. However, depending on the context, some information may be mistakenly considered as distracting, particularly when it is unexpected. According to load theory, the efficiency of selective attention depends on the level of cognitive and perceptual load during task execution. To date, IB has been primarily explained through the lens of perceptual load, with cognitive load often reduced to executive control tasks. Moreover, the interaction between these two types of load remains underexplored, as does the investigation of IB in applied contexts relevant to everyday activities. To address these gaps, the present study aims to identify the occurrence of IB during manual assembly tasks in industrial settings. A 2x2 within-subject experimental design (N=32) was implemented, independently manipulating perceptual and cognitive load. Participants performed simulated assembly tasks using LEGO components. The main dependent variable was the detection rate of an unexpected stimulus, which was briefly presented on the instruction screen. Results show a significantly higher overall rate of non-detection compared to the control condition. In addition, a high level of either cognitive or perceptual load significantly increased the rate of non-detection. A strong interaction effect between the two types of load was also observed. These findings highlight the importance of considering both cognitive and perceptual load in the design of human-machine interfaces (HMIs), especially when information is delivered dynamically. Inattentional blindness, as a cognitive bias, can affect any individual particularly in high-load environments such as assembly procedures. Modern HMIs increasingly rely on real-time adaptability and contextualized alerts. However, their effectiveness depends on the timely availability of attentional resources, which this study shows to be significantly modulated by task-induced load. Then, a visible but unexpected stimulus may go unnoticed under high load conditions. By demonstrating for the first time the occurrence of IB in an assembly task context, while simultaneously manipulating both types of load, this research reveals limitations of current HMIs and emphasizes the need to integrate this phenomenon into future interface design through a human-centered approach.