Task-irrelevant Stimuli Research Articles

Task-irrelevant stimuli reliably boost phasic pupil-linked arousal but do not affect decision formation

Task-irrelevant stimuli reliably boost phasic pupil-linked arousal but do not affect decision formation

Different effects of smooth pursuit eye movements on motion-based stimulus response congruency.

In the motion-based stimulus-response compatibility (SRC) effect, responses are faster when the task-irrelevant stimulus motion is congruent with the response movement performance. In the present study, we tested whether smooth pursuit eye movements, related to tracking a moving object, influence motion-based SRC when present on their own or when combined with position-based SRC. We examined the motion-based SRC effect during both the response selection and response execution stages. When investigating motion-based SRC alone, participants responded with left or right movements of the single hand to the left or right movements of a centrally presented stimulus, either with their eyes fixated at the center or tracking the moving object. In the case of combined motion-based and position-based SRC, participants responded with left or right movements of the left or right hand to stimulus motion presented on the left or right side of the screen, again with eyes either fixated at the center or following the moving target. Results showed that during the response selection stage, smooth pursuit type eye movements had no effect on the motion-based SRC when the stimulus moved in the center, whereas the effect was enhanced when the stimulus presentation was lateralized. This aligns with the idea that attentional shifts differ between central and peripheral vision and that cognitive system computes various spatial maps for stimulus and response. In the case of response execution, smooth pursuit type eye movements had no effect on the motion-based SRC effect, regardless of stimulus location.

Auditory distraction, time perception, and the role of age: ERP evidence from a large cohort study

Cognitive aging is typically associated with a higher susceptibility to distraction by concurrent, but task-irrelevant stimuli. Here, we studied the cognitive sub-processes involved in a sample of 484 healthy adults aged 20–70 years from the Dortmund Vital Study (Clinicaltrials.gov NCT05155397). Participants judged the duration of tone stimuli of a random sequence of long and short tones, having either a regular (standard) pitch or rare (deviant) pitch. Deviance-related ERPs were explored, reflecting neuro-cognitive correlates of pre-attentive deviance detection (MMN), attention allocation toward (P3a) and processing of (P3b) the deviance, and re-orienting toward the task-relevant stimulus feature (RON). Accuracy was reduced for deviant long tones, possibly due to withdrawing attention from processing the time information, making long stimuli appear shorter. This effect increased with age, and cluster-based permutation tests on the correlation of ERPs and age as well as linear mixed modeling indicated a decrease in MMN, an increase in P3a with long tones, and decreases in P3b and RON. This suggests a greater attentional orienting to the deviant stimulus feature and a reduced re-orienting to the task-relevant feature with increasing age.

No electrophysiological evidence for semantic processing during inattentional blindness

A long-standing question concerns whether sensory input can reach semantic stages of processing in the absence of attention and awareness. Here, we examine whether the N400, an event related potential associated with semantic processing, can occur under conditions of inattentional blindness. By employing a novel three-phase inattentional blindness paradigm designed to maximise the opportunity for detecting an N400, we found no evidence for it when participants were inattentionally blind to the eliciting stimuli (related and unrelated word pairs). In contrast, participants noticed the same task-irrelevant word pairs when minimal attention was allocated to them, and a small N400 became evident. When the same stimuli were fully attended and relevant to the task, a robust N400 was observed. In addition to univariate ERP measures, multivariate decoding analyses were unable to classify related from unrelated word pairs when observers were inattentionally blind to the words, with decoding reaching above-chance levels only when the words were (at least minimally) attended. By comparison, decoding reached above-chance levels when contrasting word pairs with non-word stimuli, even when participants were inattentionally blind to these stimuli. Our results also replicated several previous studies by finding a “visual awareness negativity” (VAN) that distinguished task-irrelevant stimuli that participants noticed compared with those that were not perceived, and a P3b (or “late positivity”) that was evident only when the stimuli were task relevant. Together, our findings suggest that semantic processing might require at least a minimal amount of attention.

The influence of task-irrelevant color perception on flanker task performance: Insights from behavioral and ERP data

Perception of color as a task-relevant stimulus can affect cognition and behavior in the flanker task; however, it remains unclear whether it has the same impact when it is a task-irrelevant stimulus dimension. To this end, we applied four-letter flanker tasks with or without colored (red/blue) to 23 healthy young adults, while recording the event-related potentials (ERPs) and behavioral performance. The flanker task included four kinds of color types: non-color letter (NC), all color letter (AC), flanker color letter (FC), and target color letter (TC), each flanker task included congruent and incongruent conditions. The behavioral data demonstrated the classic conflict effect across all color types of flanker tasks in both reaction times (RTs) and accuracy, the significant interaction and main effect of color type factors were only observed in accuracy. The ERP results showed significant interaction between conflict factor (congruent, incongruent) and color type (NC, AC, FC, and TC), and the color type factor enhanced the fronto-central P2 (180–200 ms), descended the fronto-centro-parietal N2b (260–320 ms), and increased the fronto-central P3b (360–520 ms). The fronto-central P2 and the fronto-central P3b were larger for TC than NC, AC, and FC in the congruent condition, while the fronto-central P3b was smaller for NC than AC, FC, and TC in the incongruent condition. Furthermore, the fronto-centro-parietal N2b was decreased successively in NC, AC, FC, and TC in both congruent and incongruent conditions. Overall, our findings suggested that the task-irrelevant stimuli dimension of color can capture some attentional resources and is affected by the location of color (target/flanker) and the type of task trial (congruent/incongruent) in the flanker task.

Visual continuum in non-human animals: serial dependence revealed in dogs.

Serial dependence is a recently described phenomenon by which the perceptual evaluation of a stimulus is biased by a previously attended one. By integrating stimuli over time, serial dependence is believed to ensure a stable conscious experience. Despite increasing studies in humans, it is unknown if the process occurs also in other species. Here, we assessed whether serial dependence occurs in dogs. To this aim, dogs were trained on a quantity discrimination task before being presented with a discrimination where one of the discriminanda was preceded by a task-irrelevant stimulus. If dogs are susceptible to serial dependence, the task-irrelevant stimulus was hypothesized to influence the perception of the subsequently presented quantity. Our results revealed that dogs perceived the currently presented quantity to be closer to the one presented briefly before, in accordance with serial dependence. The direction and strength of the effect were comparable to those observed in humans. Data regarding dogs' attention during the task suggest that dogs used two different quantity estimation mechanisms, an indication of a higher cognitive mechanism involved in the process. The present results are the first empirical evidence that serial dependence extends beyond humans, suggesting that the mechanism is shared by phylogenetically distant mammals.

Pre-frontal cortex guides dimension-reducing transformations in the occipito-ventral pathway for categorization behaviors

To interpret our surroundings, the brain uses a visual categorization process. Current theories and models suggest that this process comprises a hierarchy of different computations that transforms complex, high-dimensional inputs into lower-dimensional representations (i.e., manifolds) in support of multiple categorization behaviors. Here, we tested this hypothesis by analyzing these transformations reflected in dynamic MEG source activity while individual participants actively categorized the same stimuli according to different tasks: face expression, face gender, pedestrian gender, and vehicle type. Results reveal three transformation stages guided by the pre-frontal cortex. At stage 1 (high-dimensional, 50-120ms), occipital sources represent both task-relevant and task-irrelevant stimulus features; task-relevant features advance into higher ventral/dorsal regions, whereas task-irrelevant features halt at the occipital-temporal junction. At stage 2 (121-150ms), stimulus feature representations reduce to lower-dimensional manifolds, which then transform into the task-relevant features underlying categorization behavior over stage 3 (161-350ms). Our findings shed light on how the brain's network mechanisms transform high-dimensional inputs into specific feature manifolds that support multiple categorization behaviors.

Attentional set and explicit expectations of perceptual load determine flanker interference.

Task-irrelevant stimuli often capture our attention despite our best efforts to ignore them. It has been noted that tasks involving perceptually complex displays can lead to reduced interference from distractors. The mechanism behind this effect is debated, with some accounts emphasizing the "perceptual load" of the stimuli themselves and others emphasizing the role of proactive control. Here, in three experiments, we investigated the roles of perceptual load, proactive control, and reward motivation in determining distractor interference. Participants performed a visual search task of high, low, or intermediate load, with flanking task-irrelevant distractors. Each trial was preceded by a cue indicating the level of perceptual load (Experiments 1-3) as well as the potential reward that could be earned (Experiments 2 and 3). In all three experiments, the attentional set induced by the preceding trial and cued proactive expectation of perceptual load interacted to determine flanker interference, which was significant for all trial types except trials cued as high load which were also preceded by high load. These effects were not modulated by reward motivation, although in the final experiment reward did significantly improve performance overall. Thus, successful distractor exclusion does not depend upon motivation or load per se but does require an expectation of high load. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Auditory context-dependent distraction by unexpected visual stimuli.

Research findings indicate that when a task-irrelevant stimulus feature deviates from an otherwise predictable pattern, participants performing a categorization task exhibit slower responses (deviance distraction). This deviance distraction effect reflects the violation of the sensory predictions generated by the cognitive system. In this study, we sought to examine for the first time whether these predictions can be incidentally modulated by the auditory environment. Participants categorized the duration (short vs long) of a colored shape (red square or blue circle) while instructed to disregard the stimulus' visual features and the sound played in the background (two distinct chords played by different instruments). While the two visual stimuli shapes were equiprobable across the task, one was highly likely (p=.882) and the other rare (p=.118) in one auditory context and vice versa in the other context. Our results showed that participants were significantly slower in the duration judgement task whenever the stimulus was unexpected within a given auditory context (context-dependent distraction), and that the reset of their sensory predictions was completed upon the trial following a change of context. We conclude that object features and environmental context are processed in relation to each other and that sensory predictions are produced in relation to the environmental context, evidencing the first demonstration of auditory context-dependent modulation of attention.

Facial Feature-Based Attention Tracking System for Enhanced Online Learning Engagement

Recognizing and enhancing student engagement is crucial for improving learning outcomes, particularly in the context of online classes where monitoring can be challenging. Traditional methods of attendance tracking, such as calling out names, are impractical and susceptible to manipulation in the virtual environment. Students might appear 'online' without actively participating, and the absence of video feeds makes it difficult for teachers to verify attendance and attention. In order to realize a highly efficient and robust attendance management and engagement level prediction system for online learning, In the proposed System, the learner’s face is monitored by a video camera while attending a video lecture. Facial features were analyzed to predict reaction time (RT) to a task-irrelevant stimulus, which was assumed to be an index of the level of attention. Then apply a machine learning method, light Gradient Boosting Machine (LightGBM), to estimate RTs from facial features extracted as action units (AUs) corresponding to facial muscle movements by an open-source software (OpenFace). This project is to develops a user-friendly system integrated with private online learning and attendance recording system for teachers that can automatically record students ‘engagement state and attendance then generate attendance reports for online classrooms. It encompasses a novel design using the AI based FFCNN (Face Fiducial Convolution Neural Network) model to capture face biometric randomly from students’ video stream and record their attendance automatically. This integrated solution not only streamlines attendance management but also provides valuable insights into students' engagement levels through facial feature analysis.

Visual features drive attentional bias for threat

ABSTRACT Past studies argued that the attentional capture by threats is hard to inhibit. When using threats as task-irrelevant stimuli, this effect can deteriorate performance on the primary task. Whether attentional capture is driven by affective information (threat) or visual features (shape) is still debated. Here we aimed to investigate the role of threat value and shape in modulating attentional resources by conducting two experiments (total N = 87). Participants engaged in a semantic vigilance task responding to masked words appearing at the centre of the screen while ignoring threat-relevant (threatening or visually similar but nonthreatening) and neutral control distractor images placed at different distances from the target word. We found no performance difference between participants exposed to threat-related stimuli via affective or shape features. Moreover, while performance decreased when a neutral distractor appeared close (compared to further away) to the target word, stimulus eccentricity had no effect when the distractor (irrespective of the conveying feature) was threat relevant. Our findings are in line with previous studies showing an initial capture of attention by threat-relevant information but that this negative effect is compensated by an increase in arousal. We conclude that even the visual features of a stimulus can modulate attention toward threats.

Sustained training with novel distractors attenuates the behavioral interference of emotional pictures but does not affect the electrocortical markers of emotional processing.

Research has recently shown that behavioral interference prompted by emotional distractors is subject to habituation when the same exemplars are repeated, but promptly recovers in response to novel stimuli. The present study investigated whether prolonged experience with distractors that were all novel was effective in shaping the attentional filter, favoring stable and generalizable inhibition effects. To test this, the impact of emotional distractors was measured before and after a sustained training phase with only novel distractor pictures, and that for a group of participants depicted only a variety of neutral contents, whereas a different group was exposed only to emotional contents. Results showed that emotional interference on reaction times was attenuated after the training phase (compared to the pre-test), but emotional distractors continued to interfere more than neutral ones in the post-test. The two groups did not differ in terms of training effect, suggesting that the distractor suppression mechanism developed during training was not sensitive to the affective category of natural scenes with which one had had experience. The affective modulation of neither the LPP or Alpha-ERD showed any effect of training. Altogether, these findings suggest that sustained experience with novel distractors may attenuate attention allocation toward task irrelevant emotional stimuli, but the evaluative processes and the engagement of motivational systems are always needed to support the monitoring of the environment for significant cues.

Kamin blocking is disrupted by low-dose ketamine in mice: Further implications for aberrant stimulus processing in schizophrenia.

Previous studies have shown that low doses of ketamine, an N-methyl-D-aspartate receptor antagonist, produce aberrantly strong internal representations of associatively activated but absent stimuli in humans and nonhuman animals, suggesting the validity of ketamine treatment as a preclinical model of the positive symptoms of schizophrenia, including hallucinations and delusions. However, whether acute ketamine treatment also impairs the ability to ignore present but informationally redundant stimuli, which is another hallmark of schizophrenia, remains unclear. Accordingly, the present study investigated whether injections of low-dose ketamine attenuate Kamin blocking in an appetitive conditioning preparation in mice. Mice in the blocking group were initially trained with A+ conditioning (i.e., conditioned stimulus A paired with a sucrose solution), followed by compound AX+ training, before the conditioned responses to the cue X were tested in extinction. The animals in the control group received B+ training before the AX+ training. Half of the mice in each group received an injection of 16 mg/kg ketamine before each compound conditioning session and the extinction test, whereas the other half received saline. The results showed a reliable blocking effect in the saline-treated mice, whereas the blocking effect was absent in the ketamine-treated mice. Specifically, the absence of blocking was due to the ketamine-treated mice learning about the blocked cues. This finding further validates the use of low-dose ketamine as a preclinical model of schizophrenia. It also suggests a possible link between hallucination-like aberrant processing of absent events and a reduced ability to suppress attentional processing of task-irrelevant stimuli. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Stimulus-triggered task conflict affects task-selection errors in task switching: A Bayesian multinomial processing tree modeling approach.

In the present study, we used a modeling approach for measuring task conflict in task switching, assessing the probability of selecting the correct task via multinomial processing tree (MPT) modeling. With this method, task conflict and response conflict can be independently assessed as the probability of selecting the correct task and the probability of selecting the correct response within a given task, respectively. These probabilities can be estimated on the basis of response accuracy in the different experimental conditions. In two task-switching experiments, we used bivalent stimuli and manipulated irrelevant-task difficulty by varying the saliency of the stimulus feature belonging to the irrelevant task. The more salient the task-irrelevant stimulus feature, the more salient the irrelevant task, leading to more task conflict. Consistent with this assumption, we observed that task conflict, but not response conflict, was larger when the task-irrelevant stimulus feature was made more salient. Furthermore, both task conflict and response conflict were larger when the task switched than when the task was repeated. On a methodological level, the present results demonstrate that MPT modeling is a useful approach for measuring task conflict in task switching and for dissociating it from within-task response conflict. Furthermore, the present results inform theories of task switching by showing that the task-irrelevant feature tends to activate the irrelevant task set rather than being associated with a specific response option via a direct stimulus-response route. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Distinct mechanisms underlying cross-modal semantic conflict and response conflict processing.

Interference from task-irrelevant stimuli can occur during the semantic and response processing stages. Previous studies have shown both common and distinct mechanisms underlying semantic conflict processing and response conflict processing in the visual domain. However, it remains unclear whether common and/or distinct mechanisms are involved in semantic conflict processing and response conflict processing in the cross-modal domain. Therefore, the present electroencephalography study adopted an audiovisual 2-1 mapping Stroop task to investigate whether common and/or distinct mechanisms underlie semantic conflict and response conflict. Behaviorally, significant cross-modal semantic conflict and significant cross-modal response conflict were observed. Electroencephalography results revealed that the frontal N2 amplitude and theta power increased only in the semantic conflict condition, while the parietal N450 amplitude increased only in the response conflict condition. These findings indicated that distinct neural mechanisms were involved in cross-modal semantic conflict and response conflict processing, supporting the domain-specific cognitive control mechanisms from a cross-modal multistage conflict processing perspective.

Broad attention does not buffer the impact of emotionally salient stimuli on performance

ABSTRACT It has been claimed that a broad attentional breadth buffers the impact of negative stimuli on human perception and cognition. Here we identify issues with the research on which this claim is based, and then rigorously test the claim. To induce narrow versus broad attentional breadth participants attended to the local versus global elements of Navon stimuli, and to investigate the impact of emotionally salient stimuli on performance we measured the effect of task-irrelevant stimuli of varying emotional salience (negative, neutral, or positive) on task performance. Across a series of experiments, we found that the Navon stimuli were effective in inducing different attentional breadths, and that both negative and positive task-irrelevant stimuli slowed responses relative to neutral stimuli, but that the magnitude of this emotion-induced slowing was invariant to whether attentional breadth was broad or narrow. This indicates that a broad attentional breadth did not buffer against the effect of either negative or positive emotionally salient stimuli. These results challenge the claim the broadening attentional breadth protects against the impact of emotionally salient stimuli.

Neural processing of bottom-up perception of biological motion under attentional load

Considering its importance for one’s survival and social significance, biological motion (BM) perception is assumed to occur automatically. Previous behavioral results showed that task-irrelevant BM in the periphery interfered with task performance at the fovea. Under selective attention, BM perception is supported by a network of regions including the occipito-temporal (OTC), parietal, and premotor cortices. Retinotopy studies that use BM stimulus showed distinct maps for its processing under and away from selective attention. Based on these findings, we investigated how bottom-up perception of BM would be processed in the human brain under attentional load when it was shown away from the focus of attention as a task-irrelevant stimulus. Participants (N = 31) underwent an fMRI study in which they performed an attentionally demanding visual detection task at the fovea while intact or scrambled point light displays of BM were shown at the periphery. Our results showed the main effect of attentional load in fronto-parietal regions and both univariate activity maps and multivariate pattern analysis results support the attentional load modulation on the task-irrelevant peripheral stimuli. However, this effect was not specific to intact BM stimuli and was generalized to motion stimuli as evidenced by the motion-sensitive OTC involvement during the presence of dynamic stimuli in the periphery. These results confirm and extend previous work by showing that task-irrelevant distractors can be processed by stimulus-specific regions when there are enough attentional resources available. We discussed the implications of these results for future studies.

Magnetoencephalography reveals impaired sensory gating and change detection in older adults in the somatosensory system

Brain electrophysiological responses can provide information about age-related decline in sensory-cognitive functions with high temporal accuracy. Studies have revealed impairments in early sensory gating and pre-attentive change detection mechanisms in older adults, but no magnetoencephalographic (MEG) studies have been undertaken into both non-attentive and attentive somatosensory functions and their relationship to ageing. Magnetoencephalography was utilized to record cortical somatosensory brain responses in young (20–28 yrs), middle-aged (46–56 yrs), and older adults (64–78 yrs) under active and passive somatosensory oddball conditions. A repeated standard stimulus was occasionally replaced by a deviant stimulus (p = .1), which was an electrical pulse on a different finger. We examined the amplitudes of M50 and M100 responses reflecting sensory gating, and later components reflecting change detection and attention shifting (M190 and M250 for the passive condition, and M200 and M350 for the active condition, respectively). Spatiotemporal cluster-based permutation tests revealed that older adults had significantly larger M100 component amplitudes than young adults for task-irrelevant stimuli in both passive and active condition. Older adults also showed a reduced M250 component and an altered M350 in response to deviant stimuli. The responses of middle-aged adults did not differ from those of younger adults, but this study should be repeated with a larger sample size. By demonstrating changes in both somatosensory gating and attentional shifting mechanisms, our findings extend previous research on the effects of ageing on pre-attentive and attentive brain functions.

Effects of virtual reality working memory task difficulty on the passive processing of irrelevant auditory stimuli.

The virtual reality (VR) environment is claimed to be highly immersive. Participants may thus be potentially unaware of their real, external world. The present study presented irrelevant auditory stimuli while participants were engaged in an easy or difficult visual working memory (WM) task within the VR environment. The difficult WM task should be immersive and require many cognitive resources, thus few will be available for the processing of task-irrelevant auditory stimuli. Sixteen young adults wore a 3D head-mounted VR device. In the easy WM task, the stimuli were nameable objects. In the difficult WM task, the stimuli were abstract objects that could not be easily named. A novel paradigm using event-related potentials (ERPs) was implemented to examine the feasibility of quantifying the extent of processing of task-irrelevant stimuli occurring outside of the VR environment. Auditory stimuli irrelevant to the WM task were presented concurrently at every 1.5 or 12 s in separate conditions. Performance on the WM task varied with task difficulty, with accuracy significantly lower during the difficult task. The auditory ERPs consisted of N1 and a later P2/P3a deflection which were larger when the auditory stimuli were presented slowly. ERPs were unaffected by task difficulty, but significant correlations were found. N1 and P2/P3a amplitudes were smallest when performance on the Easy WM task was highest. It is possible that even the easy WM task was so immersive and required many processing resources that few were available for the co-processing of the task-irrelevant auditory stimuli.

Elevated EEG heartbeat-evoked potentials in adolescents with more ADHD symptoms

IntroductionSymptoms of attention deficit hyperactivity disorder (ADHD) are associated with a variety of mental abnormalities, but little is known about the perception and processing of internal signals, i.e., interoception, in individuals with ADHD symptoms. This study aimed to investigate the association between ADHD symptoms and the heartbeat-evoked potential (HEP), known as a neural correlate of automatic interoceptive processing of cardiac signals, in adolescents. MethodsHEPs of 47 healthy adolescent participants (53.2 % female) with a mean age of 14.29 years were measured during an emotional face recognition task. In addition, participants completed a self-report screening for ADHD symptoms. ResultsADHD symptoms were positively related to the HEP activity during the task in three of eight EEG sectors in the left hemisphere, as well as in all sectors in the right hemisphere. DiscussionThis study is the first to demonstrate preliminary a relationship between the strength of HEP activity and ADHD symptoms in awake subjects. This finding of higher HEP amplitudes in subjects with more ADHD symptoms can be interpreted in terms of (i) increased arousal, (ii) altered neural processing of internal processes in an emotion-relevant task, and (iii) a misaligned precision-weighting process of task-irrelevant stimuli according to the predictive coding framework. These different interpretations could be reflected by previous studies showing heterogeneity of psychological deficits in individuals with ADHD symptoms. However, the generalizability to patients with diagnosed ADHD is limited due to the measurement tool for ADHD symptoms and the sample characteristics.