Distractor Interference Effects Research Articles

Load effect of visual working memory on distractor interference: An investigation with two replication experiments.

Konstantinou et al. (Experiment 1B; Attention, Perception, & Psychophysics, 76, 1985-1997, 2014) reported that an increase in visual short-term memory (VSTM) load reduced distractor interference in the flanker task. Yao et al. (Experiment 3; Attention, Perception, & Psychophysics, 82, 3291-3313, 2020) replicated the design of Konstantinou et al.'s experiment and showed that the VSTM load did not modulate the distractor interference effect, contradicting the original findings. However, it is unknown whether differences in task-design between the two experiments contributed to the inconsistent results. Therefore, we first replicated the original two studies with Experiment 1 (N = 54) and Experiment 2 (N = 54) and performed a statistical comparison between the data from these two experiments. In a third experiment (N = 28), we incorporated articulatory suppression into the design to exclude possible effects of verbalization. According to the ANOVA analyses, the VSTM load did not change the level of distractor interference in all three experiments, indicating that differences in task design alone do not explain the inconsistency.

The Hybrid Model of Attentional Selection: Perceptual Load

It is a crucial cognitive skill to select the relevant ones and exclude the irrelevant ones from all the stimuli we are exposed to in our constantly changing visual environment. While the long-standing early-late selection debates on the efficient attentional selection are still relevant, a hybrid theory was proposed by Lavie and Tsal (1994). Perceptual load theory is similar to the early selection approach in that it emphasizes limited capacity, while it is similar to late selection approaches in that it emphasizes automatic processing. In line with the theory, distractor processing depends on the task-relevant perceptual load. As perceptual load increases, unrelated stimuli can easily be excluded from the attention filter; because the capacity is full. The distractor interference effect is inevitable if the perceptual load is not high enough to fill the restricted capacity. According to the theory, the perceptual load is a key factor of the locus of selection. Although many support studies have been carried out after the theory was supposed, the number of studies inconsistent with the theory's assumptions, especially in recent years, cannot be ignored. Diverse studies have shown the importance of other factors in selective attention, such as salience, proximity, similarity, and dilution effect. In conclusion, despite being an important factor, the perceptual load is not the primary determinant in efficient attentional selection.

Investigating attentional control sets: Evidence for the compilation of multi-feature control sets

Top-down control over stimulus-driven attentional capture, as postulated by the contingent capture hypothesis, has been a topic of lively scientific debate for a number of years now. According to the latter hypothesis, a stimulus has to match the feature of a top-down established control set in order to be selected automatically. Today, research on the topic of contingent capture has focused mostly on the manipulation of only a single feature separating the target from the distractors (the selection feature). The research presented here examined the compilation of top-down attentional control sets having multiple selection features. We report three experiments in which the feature overlap between the distractor and the top-down sets was manipulated on different perceptual features (e.g., colour, orientation and location). Distractors could match three, two or one of the features of the top-down sets. In line with our hypotheses, the strength of the distractor interference effects decreased linearly as the feature overlap between the distractor and the participants’ top-down sets decreased. These results therefore suggest a decline in the efficiency with which distractors involuntarily capture attention as the target-similarity decreases. The data support the idea of multi-feature attentional control sets and are discussed in light of prominent contemporary theories of visual attention.

Searching on the Back: Attentional Selectivity in the Periphery of the Tactile Field

Recent evidence has identified the N140cc lateralized component of event-related potentials as a reliable index of the deployment of attention to task-relevant items in touch. However, existing ERP studies have presented the tactile search array to participants' limbs, most often to the hands. Here, we investigated distractor interference effects when the tactile search array was presented to a portion of the body that is less lateralized and peripheral compared to the hands. Participants were asked to localize a tactile target presented among distractors in a circular arrangement to their back. The N140cc was elicited contralateral to the target when the singleton distractor was absent. Its amplitude was reduced when the singleton distractor was present and contralateral to the target, suggesting that attention was directed at least in part to the distractor when the singletons are on opposite sides. However, similar N140cc were observed when the singleton distractor was ipsilateral to the target compared to distractor absent trials. We suggest that when target and singleton distractor are ipsilateral, the exact localization of the target requires the attentional processing of all items on the same side of the array, similar to distractor absent trials. Together, these observations replicate the distractor interference effects previously observed for the hands, suggesting that analogous mechanisms guide attentional selectivity across different body parts.

Faces are not always special for attention: Effects of response–relevance and identity

Research over the past 25 years indicates that stimulus processing is diminished when attention is engaged in a perceptually demanding task of high ‘perceptual load’. These results have generalized across a variety of stimulus categories, but a controversy evolved over the question of whether perception of distractor faces (or other categories of perceptual expertise) can proceed irrespective of the level of perceptual load in the attended task. Here we identify task-relevance, and in particular identity-relevance, as a potentially important factor in explaining prior inconsistencies. In four experiments, we tested whether perceptual load in an attended letter or word task modulates the processing of famous face distractors, while varying their task-relevance. Distractor interference effects on task RTs was reduced by perceptual load not only when the faces were entirely task-irrelevant, but also when the face gender was task relevant, within a name gender classification response-competition task, using famous female or male distractor faces. However, when the identity associated with the famous faces was primed by the task using their names, as in prior demonstrations that face distractors are immune to the effects of perceptual load, we were able to replicate these prior findings. Our findings demonstrate a role for identity-priming by the relevant task in determining attentional capture by faces under high perceptual load. Our results also highlight the importance of considering even relatively subtle forms of task-relevance in selective attention research.

Does high state anxiety exacerbate distractor interference?

Attentional Control Theory states that anxiety can cause attention to be allocated to irrelevant sources of information by hindering the ability to control attention and focus on the information that matters. In a separate line of inquiry, action-centred views of attention state that non-target distractors involuntarily activate response codes that may cause interference with target-directed movements (distractor interference effect). Due to the proposed negative effects of anxiety on attentional control, we examined whether anxiety could also modulate distractor interference. Participants executed target-directed aiming movements to one of three targets with the potential of a distractor being presented at near or far locations. Distractors were presented at different times with respect to the target presentation in order to explore the excitatory (0, -100ms) and inhibitory (-850ms) processing of the distractor. As a broad indication of the effect of anxiety, the analysis of no distractor trials indicated a lower proportion of time and displacement to reach peak velocity under high compared to low anxiety conditions. Meanwhile, the typical excitatory influence of the distractors located near, compared to far, at a short distractor-onset asynchrony was found in movement time and overall response time. However, this distractor excitation was even greater under high compared to low anxiety in the reaction time component of the response. These findings broadly implicate the attentional control perspective, but they further indicate an influence of anxiety on the excitation rather than inhibition of responses.

Independent control processes? Evidence for concurrent distractor inhibition and attentional usage of distractor information

Interference evoked by a distractor presented prior to a target stimulus is reduced when the distractor-target SOA is increased, suggesting inhibition of distractor-related activation. Distractor processing is also assumed to be (strategically) adjusted to the proportions of congruent and incongruent target-distractor combinations, yielding a larger distractor interference effect when the proportion of congruent trials is higher (i.e., Proportion Congruent Effect, PCE). To explore the interplay of proportion congruent-based processing adjustment and the time course of distractor-related activation we varied the proportions of congruent and incongruent trials as well as the distractor-target SOA. To control for item-specific priming we kept distractor-related contingencies (i.e., frequency of individual distractor-target conjunctions) constant for a subset of the stimuli (and used a different subset to manipulate the proportions of congruent and incongruent trials). A PCE occurred, even for the subset of stimuli associated with constant distractor-related contingencies, thus ruling out item-specific contingency learning. Distractor interference was reduced when the SOA was increased, but this reduction did not differ between the proportion congruent conditions, as confirmed by a Bayesian analysis. Our results are consistent with independent processes pertaining to usage of distractor information for biasing response selection and distractor inhibition during the SOA. Alternative interpretations of the independent effects of the PC manipulation and the distractor-target SOA are discussed.

Steady-state visual evoked potentials reveal enhanced neural responses to illusory surfaces during a concurrent visual attention task

Under natural viewing conditions, visual stimuli are often obscured by occluding surfaces. To aid object recognition, the visual system actively reconstructs the missing information, as exemplified in the classic Kanizsa illusion, a phenomenon termed “modal completion”. Single-cell recordings in monkeys have shown that neurons in early visual cortex respond to illusory contours, but it has proven difficult to measure the neural correlates of modal completion in humans. We used electroencephalography (EEG) to measure steady-state visual-evoked potentials (SSVEPs) from disks with quarter segments removed to induce an illusory shape (or rotated to eliminate the illusory square in control trials). Opposing pairs of inducers were tagged with one of two flicker frequencies (2.5 or 4 Hz). During stimulus presentations, participants performed an attention task at fixation that required them to judge the orientation of a briefly flashed central bar while ignoring congruent (same orientation) or incongruent (different orientation) flanker bars that appeared on or off the illusory surface. Importantly, the occurrence of any illusory shape was never task relevant. Frequency-based analyses revealed that SSVEP amplitudes were reliably enhanced for trials in which an illusory square appeared, relative to control trials, at 4, 5 and 8 Hz and at an intermodulation frequency of 13 Hz. Participants' reaction times in the flanker task were significantly slower for incongruent versus congruent trials, and this distractor interference effect occurred only in the presence of an illusory surface and not in the control condition. Our results reveal a robust neural correlate of modal completion in the human visual system and provide evidence that visual completion can affect attentional control processes as deployed in a flanker task.

Context-dependent control of attention capture: Evidence from proportion congruent effects.

There are several independent demonstrations that attentional phenomena can be controlled in a context-dependent manner by cues associated with differing attentional control demands. The present set of experiments provide converging evidence that attention-capture phenomena can be modulated in a context-dependent fashion. We determined whether methods from the proportion congruent literature (listwide and item- and context-specific proportion congruent designs) that are known to modulate distractor interference effects in Stroop and flanker tasks are capable of modulating attention capture by salient feature singletons. Across experiments we found evidence that attention capture can be modulated by listwide, item-specific, and context-specific manipulations of proportion congruent. We discuss challenges associated with interpreting results from proportion congruent studies but propose that our findings converge with existing work that has demonstrated context-dependent control of attention capture. (PsycINFO Database Record

Contralesional distractors enhance ipsilesional target processing after right-hemispheric stroke

Stroke can result in marked impairments in the processing of information presented in contralesional space. The present prospective study investigated how a contralesional distractor affects ipsilesional perception in patients with a right-hemispheric stroke. In a simple target detection task, the influence of the distractor on reaction times (RTs) was examined in stroke patients and compared to the performance of healthy elderly controls. Distractor interference effects were related to measures of neglect and extinction using a regression analysis. Moreover, the magnitude of the behavioural distractor effect entered a voxel-based lesion-symptom mapping (VLSM) analysis with the hypothesis that parietal and temporoparietal lesions are related to altered distractor processing. While the presence of a distractor in the opposite hemifield slowed down RTs in healthy controls for left and right targets, this effect was only observed for contralesional left targets in the group of right-hemispheric patients. In stark contrast, the presence of a distractor in the contralesional hemifield expedited ipsilesional (i.e., right) target detection. This effect was significantly related to lesions in the anterior middle temporal and temporoparietal cortex, external and internal capsule, as well as the superior longitudinal fascicle (SLF). These results elucidate the nature of the disruption of attentive processing in the contralesional hemifield after right-hemispheric stroke. More specifically, they shed light on the abnormal prioritisation of ipsilesional information: our data suggest that damage to the temporal and temporoparietal cortex and white matter tracts may transform contralesional stimulation into an unspecific saliency signal contributing to facilitated information processing in ipsilesional space.

The formation of source memory under distraction.

BackgroundIt is vital to select and process relevant information while restraining irrelevant information for successful retrieval. When multiple streams of information are concurrently present, the ability to overcome distraction is very crucial for processing relevant information. Despite its significance, the neural mechanism of successful memory formation under distraction remains unclear, especially with memory for associations. The present fMRI study investigated the effect of distraction due to irrelevant stimuli in source memory.MethodsIn the MR scanner, participants studied an item and perceptual context with no distractor, a letter-distractor, or a word-distractor. Following the study phase, a source recognition test was administered in which participants were instructed to judge the study status of the test items and context of studied items. Participants’ encoding activity was back-sorted by later source recognition to find the influence of distractors in subsequent memory effects.ResultsSource memory with distractors recruited greater encoding activity in the left dorsolateral prefrontal cortex, and the bilateral inferior temporal gyrus/fusiform cortex, along with the left posterior hippocampus. However, enhanced activity in the left anterior ventrolateral prefrontal cortex and the left parahippocampal cortex predicted successful source memory regardless of the presence of a distractor.ConclusionsThese findings of subsequent memory effects suggest that strong binding of the item-context associations, as well as resistance to interference, may have greater premium in the formation of successful source memory of pictures under distraction. Further, attentional selection to the relevant target seems to play a major role in contextual binding under distraction by enhancing the viability of memory representations from interference effects of distractors.Electronic supplementary materialThe online version of this article (doi:10.1186/1744-9081-10-40) contains supplementary material, which is available to authorized users.

Linguistic Processing and Executive Control: Evidence for Inhibition in Broca's Aphasia

We investigated the hypothesis that inhibition is impaired in a group of Broca’s aphasics relative to a group of language-unimpaired controls. We focused on distractor interference and spatial negative priming (NP) effects, which involve the ability to inhibit (i) distracting information and (ii) irrelevant information that exerts its effect from one trial to the next, respectively. The results reflect a distractor interference effect which is in line with suggestions that inhibition is impaired in aphasia. The robust NP effect in the aphasics is accounted for in terms of a deficit in processing information on a local (vs. global) level of analysis.

Expectancies modulate attentional capture by salient color singletons

In singleton feature search for a form-defined target, the presentation of a task-irrelevant, but salient singleton color distractor is known to interfere with target detection [Theeuwes, J. (1991). Cross-dimensional perceptual selectivity. Perception & Psychophysics, 50, 184–193; Theeuwes, J. (1992). Perceptual selectivity for color and form. Perception & Psychophysics, 51, 599–606]. The present study was designed to re-examine this effect, by presenting observers with a singleton form target (on each trial) that could be accompanied by a salient) singleton color distractor, with the proportion of distractor to no-distractor trials systematically varying across blocks of trials. In addition to RTs, eye movements were recorded in order to examine the mechanisms underlying the distractor interference effect. The results showed that singleton distractors did interfere with target detection only when they were presented on a relatively small (but not on a large) proportion of trials. Overall, the findings suggest that cross-dimensional interference is a covert attention effect, arising from the competition of the target with the distractor for attentional selection [Kumada, T., & Humphreys, G. W. (2002). Cross-dimensional interference and cross-trial inhibition. Perception & Psychophysics, 64, 493–503], with the strength of the competition being modulated by observers’ (top-down) incentive to suppress the distractor dimension.

Audiotactile interactions in near and far space

In this study we investigated audiotactile spatial interactions in the region behind the head. In experiment 1, participants made unspeeded temporal order judgments (TOJs) regarding pairs of auditory and tactile stimuli presented at varying stimulus onset asynchronies (SOAs) using the method of constant stimuli. Electrocutaneous stimuli were presented to the left or right earlobe while auditory stimuli were presented from just behind the participant's head on either the same or opposite side. Participants responded significantly more accurately when the stimuli were presented from different sides rather than from the same side. In experiment 2, we used a distractor interference task to show that speeded left/right discrimination responses to electrocutaneous targets were also modulated by the spatial congruency of auditory distractors presented behind the head. Performance was worse (i.e. response latencies were slower and error rates higher) when the auditory distractors were presented on the opposite side to the electrocutaneous target than when they were presented on the same side. This crossmodal distractor interference effect was larger when white noise distractors were presented from close to the head (20 cm) than when they were presented far from the head (70 cm). By contrast, pure tone distractors elicited a smaller crossmodal distractor interference effect overall, and showed no modulation as a function of distance. Taken together, these results suggest that the spatial modulation of audiotactile interactions occurs predominantly for complex auditory stimuli (for example, white noise) originating from the region close to the back of the head.

Look Here but Ignore What You See: Effects of Distractors at Fixation.

Distractor interference effects were compared between distractors in the periphery and those placed at fixation. In 6 experiments, the authors show that fixation distractors produce larger interference effects than peripheral distractors. However, the fixation distractor effects are modulated by perceptual load to the same extent as are peripheral distractor effects (Experiments 1 and 2). Experiment 3 showed that fixation distractors are harder to filter out than peripheral distractors. The larger distractor effects at fixation are not due to the cortical magnification of foveal stimuli (Experiments 4 and 5), nor can they be attributed to cuing by the fixation point (Experiment 2), the lower predictability or greater location certainty of fixation distractors (Experiment 5), or their being in a central position (Experiment 6). The authors suggest that preferential access to attention renders fixation distractors harder to ignore than peripheral distractors.

Grasping the meaning of words.

Action affordances can be activated by non-target objects in the visual field as well as by word labels attached to target objects. These activations have been manifested in interference effects of distractors and words on actions. We examined whether affordances could be activated implicitly by words representing graspable objects that were either large (e.g., APPLE) or small (e.g., GRAPE) relative to the target. Subjects first read a word and then grasped a wooden block. Interference effects of the words arose in the early portions of the grasping movements. Specifically, early in the movement, reading a word representing a large object led to a larger grip aperture than reading a word representing a small object. This difference diminished as the hand approached the target, suggesting on-line correction of the semantic effect. The semantic effect and its on-line correction are discussed in the context of ecological theories of visual perception, the distinction between movement planning and control, and the proximity of language and motor planning systems in the human brain.

Effects of distractor load and temporal target-distractor separation on numerical comparison performance: a stimulus-competition approach.

Effects of distractor load and temporal separation between target and distractor onset were studied in a selective attention task. Two experiments required 128 participants to decide as quickly and accurately as possible which of two spatially separated one-digit numerals was larger. Targets were either preceded or succeeded by distractors with intervals of 0, 33, 83, 133, 183, and 233 msec. In Exp. 1, the target digits could appear with 0, 1, 2, or 3 one-digit distractors numerals, representing four levels of distractor load. In Exp. 2, three asterisks were used as distractors. Interference effects of digit distractors varied with distractor load and temporal separation between target and distractor onsets. Moreover, the effects of distractors preceding the target differed from distractors succeeding the target. The pattern of results provided evidence that distractor-interference effects originated from stimulus competition for selection in visual short-term memory. The results were interpreted in terms of attentional engagement theory of Duncan and Humphreys.

EFFECTS OF DISTRACTOR LOAD AND TEMPORAL TARGET-DISTRACTOR SEPARATION ON NUMERICAL COMPARISON PERFORMANCE: A STIMULUS-COMPETITION APPROACH

Effects of distractor load and temporal separation between target and distractor onset were studied in a selective attention task. Two experiments required 128 participants to decide as quickly and accurately as possible which of two spatially separated one-digit numerals was larger. Targets were either preceded or succeeded by distractors with intervals of 0, 33, 83, 133, 183, and 233 msec. In Exp. 1, the target digits could appear with 0, 1, 2, or 3 one-digit distractors numerals, representing four levels of distractor load. In Exp. 2, three asterisks were used as distractors. Interference effects of digit distractors varied with distractor load and temporal separation between target and distractor onsets. Moreover, the effects of distractors preceding the target differed from distractors succeeding the target. The pattern of results provided evidence that distractor-interference effects originated from stimulus competition for selection in visual short-term memory. The results were interpreted in terms of attentional engagement theory of Duncan and Humphreys.

Selective Reaching to Grasp: Evidence for Distractor Interference Effects

Transport and grasp kinematics were examined in a task in which subjects selectively reached to grasp a target object in the presence of non-target objects. In a variety of experiments significant interference effects were observed in temporal parameters, such as movement time, and spatial parameters, such as path. In general, the presence of non-targets slowed down the reach. Furthermore, reach paths were affected such that the hand veered away from near non-targets in reaches for far targets, even though the non-targets were not physical obstacles to the reaching hand. In contrast, the hand veered towards far non-targets in near reaches. We conclude that non-targets evoke competing responses, and the inhibitory mechanisms that resolve this competition are revealed in the reach path.

Identity negative priming in older adults and individuals with dementia of the Alzheimer type.

This study addressed the question of whether dementia of the Alzheimer type (DAT) produces a breakdown in aspects of the inhibitory component underlying selective attention. Two measures of identity negative priming and 2 measures of distractor interference were obtained. In Experiment 1, participants were presented with overlapping picture stimuli, and in Experiment 2, participants were presented with overlapping written word stimuli. The results of both experiments produced reliable and similar size negative priming in young and old adults, but there was no evidence of negative priming in the individuals with DAT. In contrast, the naming latencies of all 3 groups showed a reliable and similar size distractor interference effect. These results suggest that although the inhibitory component underlying selective attention is impaired in individuals with DAT, the ability to differentiate a target from a distractor may be preserved under certain task conditions. In the natural environment, we are confronted with multiple sources of information. One function of attention is to select some subset of this information for further processing. Many current theories of selective attention are based on the assumption that the selected or goal-relevant information is facilitated while the ignored or irrelevant information is actively inhibited (Dalrymple-Alford & Budayr, 1966; Neill, 1977; Tipper, 1985). In the present experiments, we investigate the inhibitory aspect of selective attention in healthy old adults and in individuals with dementia of the Alzheimer type (DAT). In pursuit of this goal, we first review the literature on inhibitory processes in healthy old adults and then turn to a review of the corresponding literature on individuals with DAT.