RESUMEN

Interruptions in the working environment cause extra mental workload for the operators, and this phenomenon has garnered significant research attention. This study designed four interruption conditions based on the perceptual and cognitive perspectives of human information processing, using a 2(perceptual primary task and cognitive primary task)*2(perceptual interruption task and cognitive interruption task) factorial design. Multimodal measurement methods were used to evaluate mental workload in different interruption conditions. The results show that when the primary task and the interruption task are different load types, they generate a higher mental workload than the same load type. It can be attributed to the fact that perceptual tasks and cognitive tasks increase mental workload during switching. In addition, based on the multimodal index data, the prediction model of interruption recovery delay time and the classification model of interruption conditions are established, which provides a basis for rational scheduling of work and preventing mental overload.

This study's results enhance our understanding of interruptions from the perspectives of perception and cognition, providing a more accurate theoretical basis for managing mental workload in interruption conditions. The proposed interruption recovery delay time prediction model and the interruption condition classification model have certain reference values for improving interruption management capabilities.

RESUMEN

Understanding how sensory processing demands affect the ability to ignore task-irrelevant, loud auditory stimuli (LAS) during a task is key to performance in dynamic environments. For example, tennis players must ignore crowd noise to perform optimally. We investigated how practice affects this ability by examining the effects of delivering LASs during preparatory phase of an anticipatory timing (AT) task on the voluntary and reflexive responses in two conditions: lower and higher visual processing loads. Twenty-four participants (mean age = 23.1, 11 females) completed the experiment. The AT task involved synchronizing a finger abduction response with the last visual stimulus item in a sequence of four Gabor grating patches briefly flashed on screen. The lower demand condition involved only this task, and the higher demand condition required processing the orientations of the patches to report changes in the final stimulus item. Our results showed that higher visual processing demands affected the release of voluntary actions, particularly in the first block of trials. When the perceptual load was lower, responses were released earlier by the LAS compared to the high-load condition. Practice reduced these effects largely, but high perceptual load still led to earlier action release in the second block. In contrast, practice led to more apparent facilitation of eyeblink latency in the second block. These findings indicate that a simple perceptual load manipulation can impact the execution of voluntary motor actions, particularly for inexperienced participants. They also suggest distinct movement preparation influences on voluntary and involuntary actions triggered by acoustic stimuli.

RESUMEN

Fearful, angry, and disgusted facial expressions are evolutionarily salient and convey different types of threat signals. However, it remains unclear whether these three expressions impact sensory perception and attention in the same way. The present ERP study investigated the temporal dynamics underlying the processing of different types of threatening faces and the impact of attentional resources employed during a perceptual load task. Participants were asked to judge the length of bars superimposed over faces presented in the center of the screen. A mass univariate statistical approach was used to analyze the EEG data. Behaviorally, task accuracy was significantly reduced following exposure to fearful faces relative to neutral distractors, independent of perceptual load. The ERP results revealed that the P1 amplitude over the right hemisphere was found to be enhanced for fearful relative to disgusted faces, reflecting the rapid and coarse detection of fearful cues. The N170 responses elicited by fearful, angry, and disgusted faces were larger than those elicited by neutral faces, suggesting the largely automatic and preferential processing of threats. Furthermore, the early posterior negativity (EPN) component yielded increased responses to fearful and angry faces, indicating prioritized attention to stimuli representing acute threats. Additionally, perceptual load exerted a pronounced influence on the EPN and late positive potential (LPP), with larger responses observed in the low perceptual load condition, indicating goal-directed cognitive processing. Overall, the early sensory processing of fearful, angry, and disgusted faces is characterized by differential sensitivity in capturing attention automatically, despite the importance of these facial signals for survival. Fearful faces produce a strong interference effect and are processed with higher priority than angry and disgusted ones.

Asunto(s)

RESUMEN

This study explores the effects of different perceptual and cognitive information processing stages on mental workload by assessing multimodal indicators of mental workload such as the NASA-TLX, task performance, ERPs and eye movements. Repeated measures ANOVA of the data showed that among ERP indicators, P1, N1 and N2 amplitudes were sensitive to perceptual load (P-load), P3 amplitude was sensitive to P-load only in the prefrontal region during high cognitive load (C-load) states, and P3 amplitude in the occipital and parietal regions was sensitive to C-load. Among the eye movement indicators, blink frequency was sensitive to P-load in all C-load states, but to C-load in only low P-load states; pupil diameter and blink duration were sensitive to both P-load and C-load. Based on the above indicators, the k-nearest neighbours (KNN) algorithm was used to propose a classification method for the four different mental workload states with an accuracy of 97.89%.Practitioner summary: Based on the results of this study, it is possible to implement the monitoring of mental workload states and optimise brain task allocation in operations involving high mental workload, such as human-computer interaction.

Asunto(s)

RESUMEN

Introduction: Mind wandering (MW) has been associated with reduced responsiveness to external stimuli ("perceptual decoupling"). Conversely, increased perceptual demands of a task result in reduced MW. Here we propose a neurobiological account attributing the mutually-limiting relationship of MW and perception to brain-wide limits on cerebral metabolism. Since overall cerebral metabolism is known to remain constant, despite increased mental task demands, we tested whether increased perceptual processing load in a visual task will result in reduced oxygen metabolism in MW-related medial prefrontal cortex (mPFC) regions. Methods: We used broadband near-infrared spectroscopy to measure oxidation states of the cytochrome-c-oxidase enzyme (oxCCO), an intracellular marker of metabolism, in mPFC while sampling participants' MW experiences during their performance of a visual task of either low (feature search) or high(conjunction search) perceptual load. Results: Increased perceptual load in the task resulted in reduced oxCCO signal in mPFC regions related to MW reports. High perceptual load was also found to specifically suppress detailed (and hence more metabolism-demanding) rather than vague MW. Discussion: Overall, the results support a shared metabolism account of the relationship between MW and perception and demonstrate that attentional-regulation of metabolism only supports ongoing detailed MW when perceptual processing demands are low.

RESUMEN

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder associated with suboptimal outcomes throughout the life-span. Extant work suggests that ADHD-related deficits in task performance may be magnified under high cognitive load and minimized under high perceptual load, but these effects have yet to be systematically examined, and the neural mechanisms that undergird these effects are as yet unknown. Herein, we report results from three experiments investigating how performance in ADHD is modulated by cognitive load and perceptual load during a naturalistic task. Results indicate that cognitive load and perceptual load influence task performance, reaction time variability (RTV), and brain network topology in an ADHD-specific fashion. Increasing cognitive load resulted in reduced performance, greater RTV, and reduced brain network efficiency in individuals with ADHD relative to those without. In contrast, increased perceptual load led to relatively greater performance, reduced RTV, and greater brain network efficiency in ADHD. These results provide converging evidence that brain network efficiency and intraindividual variability in ADHD are modulated by both cognitive and perceptual load during naturalistic task performance.

RESUMEN

Background: Studies have shown that deaf individuals distribute more attention to the peripheral visual field and exhibit enhanced visual processing for peripheral stimuli relative to hearing individuals. This leads to better detection of peripheral target motion and simple static stimuli in hearing individuals. However, when threatening faces that represent dangerous signals appear as non-targets in the periphery, it remains unclear whether deaf individuals would retain an advantage over hearing individuals in detecting them. Methods: In this study, 23 deaf and 28 hearing college students were included. A modified perceptual load paradigm and event-related potentials (ERPs) were adopted. In the task, participants were instructed to search for a target letter in a central letter array, while task-irrelevant face distractors (happy, neutral, and angry faces) were simultaneously presented in the periphery while the central perceptual load was manipulated. Results: Behavioral data showed that angry faces slowed deaf participants' responses to the target while facilitating the responses of hearing participants. At the electrophysiological level, we found modulation of P1 amplitude by central load only in hearing individuals. Interestingly, larger interference from angry face distractors was associated with higher P1 differential amplitude only in deaf individuals. Additionally, the amplitude of N170 for happy face distractors was smaller than that for angry and neutral face distractors in deaf participants. Conclusion: The present data demonstrates that, despite being under central perceptual load, deaf individuals exhibit less attentional inhibition to peripheral, goal-irrelevant angry faces than hearing individuals. The result may reflect a compensatory mechanism in which, in the absence of auditory alertness to danger, the detection of visually threatening information outside of the current attentional focus has a high priority.

RESUMEN

Highly-automated technologies are increasingly incorporated into existing systems, for instance in advanced car models. Although highly automated modes permit non-driving activities (e.g. internet browsing), drivers are expected to reassume control upon a 'take over' signal from the automation. To assess a person's readiness for takeover, non-invasive eye tracking can indicate their attentive state based on properties of their gaze. Perceptual load is a well-established determinant of attention and perception, however, the effects of perceptual load on a person's ability to respond to a takeover signal and the related gaze indicators are not yet known. Here we examined how load-induced attentional state affects detection of a takeover-signal proxy, as well as the gaze properties that change with attentional state, in an ongoing task with no overt behaviour beyond eye movements (responding by lingering the gaze). Participants performed a multi-target visual search of either low perceptual load (shape targets) or high perceptual load (targets were two separate conjunctions of colour and shape), while also detecting occasional auditory tones (the proxy takeover signal). Across two experiments, we found that high perceptual load was associated with poorer search performance, slower detection of cross-modal stimuli, and longer fixation durations, while saccade amplitude did not consistently change with load. Using machine learning, we were able to predict the load condition from fixation duration alone. These results suggest monitoring fixation duration may be useful in the design of systems to track users' attentional states and predict impaired user responses to stimuli outside of the focus of attention.

Asunto(s)

RESUMEN

The aim of this study was to examine whether peripheral information facilitates proactive processes during multitasking. For this purpose, peripheral information was presented regularly during multitasking and its effects on the performance of a tracking task (main task: reactive process) and a discrimination task (sub-task: proactive process) were examined. Experiment 1 presented peripheral information (white circles) in the same sensory modality (visual) as the information used for multitasking and the number of circle presentations was manipulated. In Experiment 2, a pure tone (auditory) was presented as peripheral information. We found that, in both experiments, the difficulty of the tracking task influenced discrimination performance, showing that as the difficulty of the tracking task (reactive process) increased, more cognitive resources were consumed in the tracking task, resulting in a decrease in cognitive resources available for the discrimination task (proactive process). In addition, regular presentation of peripheral information facilitated discrimination task performance in both experiments. Interestingly, this peripheral information also facilitated the tracking task performance (reactive process) even if the tracking task was difficult. Moreover, this promoting effect of the peripheral information occurred regardless of the sensory modality. This study revealed that processing of peripheral information facilitates the proactive process even if more cognitive resources are consumed, and that this facilitating effect does not conflict with multitasking and provides a margin of cognitive resources and also facilitates the reactive process. Our results provide evidence of how peripheral information and cognitive resources are used during multitasking.

RESUMEN

BACKGROUND AND OBJECTIVES: Schizophrenia-spectrum disorders (SSD) are characterized by impaired emotion processing and attention. SSD patients are more sensitive to the presence of emotional distractors. But despite growing interest on the emotion-attention interplay, emotional interference in SSD is far from fully understood. Moreover, research to date has not established the link between emotional interference and attentional control in SSD. This study thus aimed to investigate the effects of facial expression and attentional control in SSD, by manipulating perceptual load. METHODS: Twenty-two SSD patients and 22 healthy controls performed a target-letter discrimination task with task-irrelevant angry, happy, and neutral faces. Target-letter was presented among homogenous (low load) or heterogenous (high load) distractor-letters. Accuracy and RT were analysed using (generalized) linear mixed-effect models. RESULTS: Accuracy was significantly lower in SSD patients than controls, regardless of perceptual load and facial expression. Concerning RT, SSD patients were significantly slower than controls in the presence of neutral faces, but only at high load. No group differences were observed for angry and happy faces. LIMITATIONS: Heterogeneity of SSD, small sample size, lack of clinical control group, medication. CONCLUSIONS: One possible explanation is that neutral faces captured exogenous attention to a greater extent in SSD, thus challenging attentional control in perceptually demanding conditions. This may reflect abnormal processing of neutral faces in SSD. If replicated, these findings will help to understand the interplay between exogenous attention, attentional control, and emotion processing in SSD, which may unravel the mechanism underlying socioemotional dysfunction in SSD.

Asunto(s)

RESUMEN

Humans tend to focus on others' gaze. Previous studies have shown that the gaze direction of others can induce corresponding attentional orienting. However, gaze cues have typically been presented alone in these studies. It is unclear how gaze cues induce observers' attention in complicated contexts with additional perceptual information. Therefore, the present study investigated gaze-induced attentional orienting at different levels of perceptual load. Results indicated that the attentional effect of the dynamic gaze cue (i.e., GCE: gaze cue effect) emerged under low perceptual load and disappeared under high perceptual load. The absence of GCE could not attribute to perceptual capacity exhaustion. Moreover, the influence of perceptual load on gaze-induced attentional orienting was modulated by individuals' expectation. Specifically, the GCE occurred under high perceptual load when the gaze cue was predictive (with individuals' expectation). These findings provide new evidence on the mode of gaze-induced attentional orienting under different perceptual load conditions.

RESUMEN

Although the eye region has been found to convey sufficient information for emotional recognition and interpersonal communication, little is known regarding the extent to which the prioritized processing of emotional eye regions relies on available attentional resources. To address this issue, the present study used a dual-target rapid serial visual presentation task in which the perceptual load levels of the first target (T1), as well as the valence of the second target (T2), were manipulated. In addition to the traditional event-related potential (ERP) analysis method, the mass univariate statistics approach was employed. Behaviorally, both happy and fearful eye regions were recognized more accurately than neutral eye regions, regardless of the T1 perceptual load. ERP findings revealed an enhanced N170 amplitude for fearful eye regions compared to neutral eye regions, confirming the preferential and automatic processing of fearful signals at the early sensory stage. The late positive potential component exhibited enhanced responses to fearful and happy eye regions, suggesting the amplified representation consolidation in working memory. Collectively, these findings indicate that isolated eye regions are processed automatically to a higher degree owing to their perceptual and motivational significance.

Asunto(s)

RESUMEN

Load Theory states that perceptual load prevents, or at least reduces, the processing of task-unrelated stimuli. This study systematically examined the detection and neural processing of auditory stimuli unrelated to a visual foreground task. The visual task was designed to create continuous perceptual load, alternated between low and high load, and contained performance feedback to motivate participants to focus on the visual task instead of the auditory stimuli presented in the background. The auditory stimuli varied in intensity, and participants signaled their subjective perception of these stimuli without receiving feedback. Depending on stimulus intensity, we observed load effects on detection performance and P3 amplitudes of the event-related potential (ERP). N1 amplitudes were unaffected by perceptual load, as tested by Bayesian statistics. Findings suggest that visual perceptual load affects the processing of auditory stimuli in a late time window, which is associated with a lower probability of reported awareness of these stimuli.

Asunto(s)

RESUMEN

Although the mechanisms of target enhancement and distractor suppression have been investigated along the visual processing hierarchy, there remains some unknown as to the role of perceptual load on the competition between different task-related information as attention deployment is manipulated. We present an fMRI spatial cueing paradigm, in which 32 participants had to attend to either a left or a right hemifield location and to indicate the orientation of the target Gabor that was presented simultaneously to a noise patch distractor. Critically, the target could appear at either the cued, valid location or at the uncued, invalid location; in the latter, the noise patch distractor appeared at the cued location. Perceptual load was manipulated by the presence or absence of high-contrast Gabor patches close to the fixation cross, which acted as lateral masks. Behavioural results indicated that participants performed more efficiently in validly cued trials compared to invalidly cued trials and under low compared to high load. Enhancement effects for targets and suppression effects for noise patches were greater in early visual areas at high load, that is in the presence of lateral masks. These results are in line with the hypothesis that attention results in both target enhancement and distractor suppression, and that these effects are most marked under high perceptual load. Theoretical implications of these results for different models of attention are discussed.

Asunto(s)

RESUMEN

INTRODUCTION: A high perceptual load can effectively prevent attention from being drawn to irrelevant stimuli; however, the neural pattern underlying this process remains unclear. METHODS: This study adopted a perceptual load paradigm to examine the temporal processes of attentional modulation by incorporating conditions of perceptual load, distractor-target compatibility, and eccentricity. RESULTS: The behavioral results showed that a high perceptual load significantly reduced attentional distraction caused by peripheral distractors. The event-related potential results further revealed that shorter P2 latencies were observed for peripheral distractors than for central distractors under a high perceptual load and that a suppressed compatibility effect with increasing load was reflected by the P3 component. CONCLUSION: These findings suggested that (1) P2 and P3 components effectively captured different sides of attentional processing modulated by load (i.e., the filter processing of the object and the overall attentional resource allocation) and (2) response patterns of selective attention modulated by perceptual load were influenced by eccentricity. Our electrophysiological evidence confirmed the behavioral findings, indicating the neural mechanisms of attentional modulation.

Asunto(s)

RESUMEN

Successful performance of a task relies on selectively attending to the target, while ignoring distractions. Studies on perceptual load theory (PLT), conducted involving independent tasks with visual and auditory modalities, have shown that if a task is low-load, distractors and the target are both processed. If the task is high-load, distractions are not processed. The current study expands these findings by considering the effect of cross-modality (target and distractor from separate modalities) and congruency (similarity of target and distractor) on selective attention, using a word-identification task. Parameters were analysed, including response time, accuracy rates, congruency of distractions, and subjective report of load. In contrast to past studies on PLT, the results of the current study show that modality (congruency of the distractors) had a significant effect and load had no effect on selective attention. This study demonstrates that subjective measurement of load is important when studying perceptual load and selective attention.

RESUMEN

BACKGROUND: Inconsistent observations of pupillary response and blink change in response to different specific tasks raise questions regarding the relationship between eye measures, task types and working memory (WM) models. On the one hand, studies have provided mixed evidence from eye measures about tasks: pupil size has mostly been reported to increase with increasing task demand while this expected change was not observed in some studies, and blink rate has exhibited different trends in different tasks. On the other hand, a WM model has been developed to integrate a component to reconcile recent findings that the human motor system plays an important role in cognition and learning. However, how different tasks correlate with WM components has not been experimentally examined using eye activity measurements. AIMS: The current study uses a four-dimensional task load framework to bridge eye measures, task types and WM models. SAMPLE: Twenty participants (10 males, 10 females; Age: M = 25.8, SD = 7.17) above 18 years old volunteered. All participants had normal or corrected to normal vision with contact lenses and had no eye diseases causing obvious excessive blinking. METHODS: We examined the ability of pupil size and blink rate to index low and high levels of cognitive, perceptual, physical and communicative task load. A network of the four load types and WM components was built and analysed to verify the necessity of integrating a physical task-related component into the WM model. RESULTS: Results demonstrate that pupil size can index cognitive load and communicative load but not perceptual or physical load. Blink rate can index the level of cognitive load but is best at discriminating perceptual tasks from other types of tasks. Furthermore, pupil size measurement of the four task types was explained better during structural and factor analysis by a WM model that integrates a movement-related component. CONCLUSIONS: This research provides new insights into the relationship between eye measures, task type and WM models and provides a comprehensive understanding from which to predict pupil size and blink behaviours in more complex and practical tasks.

Asunto(s)

RESUMEN

Unilateral neglect is a common cognitive syndrome after stroke, which is defined as a spatially specific unawareness of the contralesional space. The syndrome is caused by disruptions of attentional networks in the brain, which impair the patients' ability to direct attention towards the contralesional space. During recovery, patients often learn to compensate by voluntarily directing their attention to the neglected side at the expense of cognitive resources. In this study, we examined the impact of the complexity of visual input on free visual exploration behavior of unilateral neglect and apparently recovered patients. We asked whether increasing scene complexity would allow the detection of residual unilateral neglect in recovered patients by increasing the amount of cognitive resources needed for visual processing and limiting capacities for compensation. Using virtual reality, we analyzed the spatial distribution of gaze of unilateral neglect patients, patients who had, according to conventional diagnostics, recovered from the syndrome, stroke patients with no history of unilateral neglect, and age-matched healthy controls. We manipulated the complexity of an immersive virtual scene presented on head mounted displays. We identified the orientation bias towards the ipsilesional side as a sensitive and specific marker of unilateral neglect, which was present in unilateral neglect and recovered patients but absent in stroke patients with no history of unilateral neglect and controls. Increasing scene complexity exacerbated the orientation shift in unilateral neglect patients and revealed that three out of nine (33%) recovered patients had a high probability of suffering from residual unilateral neglect as estimated by a generalized linear model using the median horizontal gaze position as a predictor.

Asunto(s)

RESUMEN

There is an ongoing debate on how different components of the event-related potential (ERP) to threat-related facial expressions are modulated by attentional conditions and interindividual differences in trait anxiety. In the current study (N = 80), we examined ERPs to centrally presented, task-irrelevant fearful and neutral faces, while participants had to solve a face-unrelated visual task, which differed in difficulty and spatial position. Critically, we used a fixation-controlled experimental design and ensured the spatial attention manipulation by spectral analysis of the EEG. Besides the factors emotion, spatial attention, and perceptual load, we also investigated correlations between trait anxiety and ERPs. While P1 emotion effects were insignificant, the N170 was increased to fearful faces regardless of load and spatial attention conditions. During the EPN time window, a significantly increased negativity for fearful faces was observed only during low load and spatial attention to the face. We found no significant relationship between ERPs and trait anxiety, questioning the hypothesis of a general hypersensitivity toward fearful expressions in anxious individuals. These results show a high resistance of the N170 amplitude increase for fearful faces to spatial attention and task load manipulations. By contrast, the EPN modulation by fearful faces index a resource-dependent stage of the ERP, requiring both spatial attention at the location of faces and low load of the face-irrelevant task.

Asunto(s)

RESUMEN

Attention serves an essential role in cognition and behavior allowing us to focus on behaviorally-relevant objects while ignoring distraction. Perceptual load theory states that attentional resources are allocated according to the requirements of the task, i.e., its 'load'. The theory predicts that the resources left to process irrelevant, possibly distracting stimuli, are reduced when the perceptual load is high. However, it remains unclear how this allocation of attentional resources specifically relates to neural excitability and suppression mechanisms. In this magnetoencephalography (MEG) study, we show that brain oscillations in the alpha band (8-13 Hz) implemented the suppression of distracting objects when the perceptual load was high. In parallel, high load increased the neuronal excitability for target objects, as reflected by rapid invisible frequency tagging. We suggest that the allocation of resources in tasks with high perceptual load is implemented by a gain increase for targets, complemented by distractor suppression reflected by alpha-band oscillations closing the 'gate' for interference.

Asunto(s)