Nontarget Items Research Articles

Conjunction search: Can we simultaneously bias attention to features and relations?

Attention allows selection of sought-after objects by tuning attention in a top-down manner to task-relevant features. Among other possible search modes, attention can be tuned to the exact feature values of a target (e.g., red, large), or to the relative target feature (e.g., reddest, largest item), in which case selection is context dependent. The present study tested whether we can tune attention simultaneously to a specific feature value (e.g., specific size) and a relative target feature (e.g., relative color) of a conjunction target, using a variant of the spatial cueing paradigm. Tuning to the specific feature of the target was encouraged by randomly presenting the conjunction target in a varying context of nontarget items, and feature-specific versus relational tuning was assessed by briefly presenting conjunction cues that either matched or mismatched the relative versus physical features of the target. The results showed that attention could be biased to the specific size and the relative color of the conjunction target or vice versa. These results suggest the existence of local and relatively low-level attentional control mechanisms that operate independently of each other in separate feature dimensions (color, size) to choose the best search strategy in line with current top-down goals.

Differential prediction of antidepressant treatment response via measurement of baseline adiponectin level: findings from the CO-MED randomized clinical trial

While clinical studies showed paradoxical memory phenomena, including the intrusion and amnesia of stressful experiences that are features of dissociation, the results of laboratory studies on dissociative individuals’ forgetting of experimental stimuli through cognitive control varied. Some studies demonstrated ineffective inhibition, and others found that dissociative individuals could remember fewer trauma words in a divided-attention context. Dissociative individuals may utilize superior cognitive disengagement to forget the representations. This hypothesis was tested in nonclinical individuals with high, medium, and low dissociation proneness. In the study phase, the participants learned several lists of experimental words and kept updating working memory by remembering the last four items on a list (target) and ignoring those non-target items. A recognition test was then conducted. The high dissociation group performed better on updating working memory. However, the accessibility of the representations of neutral and negative non-target items was elevated. Dissociative individuals disengaged attention effectively from items they intended to ignore, and the representations of the ignored items were more accessible when cues were available.

Cue Combinatorics in Memory Retrieval for Anaphora.

Many studies have shown that memory retrieval for real-time language processing relies on a cue-based access mechanism, which allows the cues available at the retrieval site to directly access the target representation in memory. An open question is how different types of cues are combined at retrieval to create a single retrieval probe ("cue combinatorics"). This study addresses this question by testing whether retrieval for antecedent-reflexive dependencies combines cues in a linear (i.e., additive) or nonlinear (i.e., multiplicative) fashion. Results from computational simulations and a reading time experiment show that target items that match all the cues of the reflexive are favored more than target items that mismatch these cues, and that different degrees of mismatches slow reading times in comparable amounts. This profile is consistent with the predictions of a nonlinear cue combination and provides evidence against models in which all cues combine in a linear fashion. A follow-up set of simulations shows that a nonlinear rule also captures previous demonstrations of interference from nontarget items during retrieval for reflexive licensing. Taken together, these results shed new light on how different types of cues combine at the retrieval site and reveal how the method of cue combination impacts the accessibility of linguistic information in memory.

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

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

Sex Differences in Temporal but Not Spatial Attentional Capture.

The accuracy of detecting or identifying a target decreases when a salient distractor is presented. This decrease is explained by the temporal or spatial diversion of attention to the distractor and thus is referred to as attentional capture. Using temporal and spatial visual search tasks, we examined whether there are sex differences in attentional capture. In Experiment 1A, a temporal visual search task measured attentional capture in the temporal domain by asking participants (97 men and 92 women) to identify a target embedded in a rapid stream of nontarget letters while ignoring a preceding peripheral distractor. In Experiment 2, a spatial visual search task measured attentional capture in the spatial domain by asking participants (146 men and 83 women) to detect a target among spatially distributed nontarget items while ignoring a distractor presented simultaneously. Our results indicate that attentional capture occurred in both tasks. In Experiment 1A, the magnitude of capture was significantly larger for women than men. In Experiment 1B, we confirmed sex differences in temporal attentional capture by recruiting a new set of participants (141 men and 85 women). In Experiment 2, the magnitude of capture was comparable between the sexes. These results suggest that women are more sensitive to bottom-up signals than men when they engage in a temporal search task and could be explained in terms of sex differences in the ability of adjusting the size of attentional window, within which attention is allocated to the most salient item.

Probing the mental representation of quantifiers

In this study, we investigate the mental representation of non-numerical quantifiers (“some”, “many”, “all”, etc.) by comparing their use in abstract and in grounded perceptual contexts. Using an approach similar to that used in the number domain, we test whether (and to what extent) such representation is constrained by the way we perceive the world through our senses. In two experiments, subjects either judged the similarity of quantifier pairs (presented as written words) or chose among a predetermined list of quantifiers the one that best described a visual image depicting a variable number of target and non-target items. The results were rather consistent across experiments, and indicated that quantifiers are mentally organized on an ordered but non-linear compressed scale where the quantifiers that imply small quantities appear more precisely differentiated across each other compared to those implying large quantities. This fits nicely with the idea that we construct our representations of such symbols mainly by mapping them to the representations of quantities that we derive from perception.

Transition from feature-search to singleton-detection strategies in visual search: The role of number of target-defining options.

When searching for a uniquely colored target in an RSVP stream of homogeneously colored nontarget items, observers can use singleton-detection and/or feature-search modes. Using an attentional-capture paradigm, we varied systematically (a) the number of possible target colors from 1 to 4 and (b) the presence or absence of a colored ring surrounding the nontarget item displayed 200 ms before the target. When present, the ring was either the same color as 1 of the possible targets (color-match), or an irrelevant color (color-mismatch). Capture was measured as the impairment in target identification accuracy when the ring was present relative to when it was absent. Greater capture in the color-match than in the color-mismatch condition was regarded as evidence of feature-search mode. Capture in the color-mismatch condition was regarded as evidence for singleton-detection mode. We show that, as the number of target colors is increased, the relative prominence of feature-search mode decreases, and that of singleton-detection mode increases correspondingly. This novel finding shows that, when both feature-search and singleton-detection modes are possible, at least some degree of feature-search mode is used until the number of possible target-defining colors reaches about 4. This suggests that the weight assigned to singleton-detection mode increases, and that assigned to feature-search mode decreases correspondingly, as the difficulty of maintaining the target-defining features in mind is increased. (PsycINFO Database Record

Enhanced accessibility of ignored neutral and negative items in nonclinical dissociative individuals

While clinical studies showed paradoxical memory phenomena, including the intrusion and amnesia of stressful experiences that are features of dissociation, the results of laboratory studies on dissociative individuals' forgetting of experimental stimuli through cognitive control varied. Some studies demonstrated ineffective inhibition, and others found that dissociative individuals could remember fewer trauma words in a divided-attention context. Dissociative individuals may utilize superior cognitive disengagement to forget the representations. This hypothesis was tested in nonclinical individuals with high, medium, and low dissociation proneness. In the study phase, the participants learned several lists of experimental words and kept updating working memory by remembering the last four items on a list (target) and ignoring those non-target items. A recognition test was then conducted. The high dissociation group performed better on updating working memory. However, the accessibility of the representations of neutral and negative non-target items was elevated. Dissociative individuals disengaged attention effectively from items they intended to ignore, and the representations of the ignored items were more accessible when cues were available.

Atypical Processing of Novel Distracters in a Visual Oddball Task in Autism Spectrum Disorder.

Several studies have shown that children with autism spectrum disorder (ASD) show abnormalities in P3b to targets in standard oddball tasks. The present study employed a three-stimulus visual oddball task with novel distracters that analyzed event-related potentials (ERP) to both target and non-target items at frontal and parietal sites. The task tested the hypothesis that children with autism are abnormally orienting attention to distracters probably due to impaired habituation to novelty. We predicted a lower selectivity in early ERPs to target, frequent non-target, and rare distracters. We also expected delayed late ERPs in autism. The study enrolled 32 ASD and 24 typically developing (TD) children. Reaction time (RT) and accuracy were analyzed as behavioral measures, while ERPs were recorded with a dense-array EEG system. Children with ASD showed higher error rate without normative post-error RT slowing and had lower error-related negativity. Parietal P1, frontal N1, as well as P3a and P3b components were higher to novels in ASD. Augmented exogenous ERPs suggest low selectivity in pre-processing of stimuli resulting in their excessive processing at later stages. The results suggest an impaired habituation to unattended stimuli that incurs a high load at the later stages of perceptual and cognitive processing and response selection when novel distracter stimuli are differentiated from targets.

Positive and Negative Consequences of Making Coffee among Breakfast Related Irrelevant Objects: Evidence from MCI, Dementia, and Healthy Ageing.

Previous studies have reported impairments in activities of daily living (ADL) performance in the presence of irrelevant but physically/functionally related objects in dementia patients. The aim of the present study was to increase our knowledge about the impact of the presence of contextually related non-target objects on ADL execution in patients with multi-domain mild cognitive impairment (MCI) and dementia. We compared ADL execution in patients with MCI, dementia, and healthy elderly participants under two experimental conditions: One in which the target objects were embedded with contextually related non-target items that constituted the object set necessary to complete two additional (but unrequired) ADL tasks related to the target task, and a second, control condition where target objects were surrounded by isolated objects (they never constituted a whole set needed to complete an alternative ADL task). Separate analysis of ADL errors associated with the target task versus errors involving the non-target objects revealed that, although the presence of contextually related objects facilitated the accomplishment of the target task, such a condition also led to errors involving the use of irrelevant objects in dementia and MCI. The presence of contextually related non-target items produces both positive and negative effects on ADL performance. These types of non-target objects might help to cue the retrieval of the action schema related to the target task, particularly in patients with MCI. In contrast, the presence of these objects might also lead to distraction in dementia and MCI. (JINS, 2017, 23, 481-492).

Do sudden onsets need to be perceived as new objects to capture attention? The interplay between sensory transients and display configuration

Yantis and Jonides (1984) and Jonides and Yantis (1988) reported robust involuntary attentional capture by sudden-onsets, the origin of which has been debated. Prominent accounts have highlighted aspects that include the "new object" status of a sudden-onset (Yantis & Hillstrom, 1994) and the substantial luminance changes accompanying their appearance (Gellatly, Cole & Blurton, 1999; Franconeri, Hollingworth & Simons, 2005), including relative differences in the amount of sensory change between target and nontarget items (Pinto, Olivers & Theeuwes, 2008). In this research we dissociate the amount of sensory change accompanying sudden onsets from the extent to which they appear as newly created objects in search displays. We attempted to determine the relative contribution of local sensory changes and display configuration to attentional capture by sudden-onsets. We showed that the display configuration of old objects modulates the impact of capture caused by sudden-onsets.

Spatiotemporal proximity effects in visual short-term memory examined by target-nontarget analysis.

Visual short-term memory (VSTM) is a limited-capacity system that holds a small number of objects online simultaneously, implying that competition for limited storage resources occurs (Phillips, 1974). How the spatial and temporal proximity of stimuli affects this competition is unclear. In this 2-experiment study, we examined the effect of the spatial and temporal separation of real-world memory targets and erroneously selected nontarget items examined during location-recognition and object-recall tasks. In Experiment 1 (the location-recognition task), our test display comprised either the picture or name of 1 previously examined memory stimulus (rendered above as the stimulus-display area), together with numbered square boxes at each of the memory-stimulus locations used in that trial. Participants were asked to report the number inside the square box corresponding to the location at which the cued object was originally presented. In Experiment 2 (the object-recall task), the test display comprised a single empty square box presented at 1 memory-stimulus location. Participants were asked to report the name of the object presented at that location. In both experiments, nontarget objects that were spatially and temporally proximal to the memory target were confused more often than nontarget objects that were spatially and temporally distant (i.e., a spatiotemporal proximity effect); this effect generalized across memory tasks, and the object feature (picture or name) that cued the test-display memory target. Our findings are discussed in terms of spatial and temporal confusion "fields" in VSTM, wherein objects occupy diffuse loci in a spatiotemporal coordinate system, wherein neighboring locations are more susceptible to confusion. (PsycINFO Database Record

Semantic context effects on picture naming in aphasia

Semantic context effects on picture naming in aphasia

Retrieval practice can insulate items against intralist interference: Evidence from the list-length effect, output interference, and retrieval-induced forgetting.

This study sought to determine whether nonselective retrieval practice after study can reduce memories' susceptibility to intralist interference, as it is observed in the list-length effect, output interference, and retrieval-induced forgetting. Across 3 experiments, we compared the effects of nonselective retrieval practice and restudy on previously studied material with regard to these 3 forms of episodic forgetting. When study of an item list was followed by a restudy cycle, recall from a longer list was worse than recall from a shorter list (list-length effect), preceding recall of studied nontarget items impaired recall of the list's target items (output interference), and repeated selective retrieval of some list items attenuated recall of other nonretrieved items at test (retrieval-induced forgetting). In contrast, none of these effects arose when study of the list was followed by a nonselective retrieval cycle. The findings are consistent with a combination of contextual variability theory and a variant of study-phase retrieval theory that assumes that retrieval can create more distinct context features for retrieved items than restudy does for restudied items, thus reducing items' susceptibility to interference relative to restudy cycles. The findings add to the view that nonselective retrieval practice can stabilize and consolidate memories.

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

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

Cognitive Control of Episodic Memory in Schizophrenia: Differential Role of Dorsolateral and Ventrolateral Prefrontal Cortex

Background: Dorsal (DLPFC) and ventral (VLPFC) subregions in lateral prefrontal cortex play distinct roles in episodic memory, and both are implicated in schizophrenia. We test the hypothesis that schizophrenia differentially impairs DLPFC versus VLPFC control of episodic encoding.Methods: Cognitive control was manipulated by requiring participants to encode targets and avoid encoding non-targets based upon stimulus properties of test stimuli. The more automatic encoding response (target versus non-target) was predicted to engage VLPFC in both groups. Conversely, having to overcome the prepotent encoding response (non-targets versus targets) was predicted to produce greater DLPFC activation in controls than in patients. Encoding occurred during event-related fMRI in a sample of 21 individuals with schizophrenia and 30 healthy participants. Scanning was followed by recognition testing outside the scanner.Results: Patients were less successful differentially remembering target versus non-target stimuli, and retrieval difficulties correlated with more severe disorganized symptoms. As predicted, the target versus non-target contrast activated the VLPFC and correlated with retrieval success in both groups. Conversely, the non-target versus target contrast produced greater DLPFC activation in controls than in patients, and DLPFC activation correlated with performance only in controls.Conclusion: Individuals with schizophrenia can successfully engage the VLPFC to provide control over semantic encoding of individual items, but are specifically impaired at engaging the DLPFC to main context for task-appropriate encoding and thereby generate improved memory for target versus non-target items. This extends previous cognitive control models based on response selection tasks to the memory domain.

Choice reaching with a LEGO arm robot (CoRLEGO): The motor system guides visual attention to movement-relevant information

We present an extension of a neurobiologically inspired robotics model, termed CoRLEGO (Choice reaching with a LEGO arm robot). CoRLEGO models experimental evidence from choice reaching tasks (CRT). In a CRT participants are asked to rapidly reach and touch an item presented on the screen. These experiments show that non-target items can divert the reaching movement away from the ideal trajectory to the target item. This is seen as evidence attentional selection of reaching targets can leak into the motor system. Using competitive target selection and topological representations of motor parameters (dynamic neural fields) CoRLEGO is able to mimic this leakage effect. Furthermore if the reaching target is determined by its colour oddity (i.e. a green square among red squares or vice versa), the reaching trajectories become straighter with repetitions of the target colour (colour streaks). This colour priming effect can also be modelled with CoRLEGO. The paper also presents an extension of CoRLEGO. This extension mimics findings that transcranial direct current stimulation (tDCS) over the motor cortex modulates the colour priming effect (Woodgate et al., 2015). The results with the new CoRLEGO suggest that feedback connections from the motor system to the brain’s attentional system (parietal cortex) guide visual attention to extract movement-relevant information (i.e. colour) from visual stimuli. This paper adds to growing evidence that there is a close interaction between the motor system and the attention system. This evidence contradicts the traditional conceptualization of the motor system as the endpoint of a serial chain of processing stages. At the end of the paper we discuss CoRLEGO’s predictions and also lessons for neurobiologically inspired robotics emerging from this work.

A guess today may be a strategic error tomorrow: Predicting intra-individual differences in visual working memory

Inter-individual differences in visual working memory (VWM) are well documented, however, there has been less work exploring intra-individual differences or how VWM processes may fluctuate over time in healthy young adults. It has also been documented that VWM is impacted by changes in female sex hormones in menopausal woman, however, these hormones also fluctuate across the monthly cycle in young woman, granted to a lesser extent. Given the high prevalence of female participants in the majority of VWM studies, understanding whether there are in fact intra-individual changes in VWM performance over the monthly cycle may not only provide a novel contribution to the discussion of fixed vs. flexible capacities in VWM, but may also help explain unreplicable results or inconsistencies in the literature. Here, we compared performance on a VWM colour-wheel task in women at two time-points (at menstruation and ovulation). Employing the 3-component swap model of VWM (Bays, Catalao, & Husain, 2009), we estimated measures of probability of target, non-target (swaps between target and non-target items), and guess responses, addressing the question of whether VWM performance varies over time within individuals and whether this is due to changes in the number of target responses or the types of errors made. Interestingly the probability of target response did not differ between the two time-points, however, the types of errors did. When VWM is at capacity (load 4 and 6) women made more swap errors at ovulation and more guesses at menstruation. These results suggest that the amount of information held in VWM may increase at ovulation but this results in more interference, with no concomitant increase in target responses. These results reveal the presence of intra-individual differences in VWM performance (types of errors made) that follow cyclical patterns in the monthly hormone cycle in young woman. Meeting abstract presented at VSS 2015

Differences between target and non-target probe processing — Combined evidence from fMRI, EEG and fMRI-constrained source analysis

Previous studies reported heterogeneous findings in working memory tasks when examining differences between correct recognition (targets) and correct rejection (non-targets). In the present study, twenty human participants completed a delayed match-to-sample task in two separate functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) sessions. Targets and non-target items were presented at different within-trial positions. We used fMRI-constrained source analysis to investigate the spatio-temporal neuronal dynamics of probe processing.Probe type-related differences were modulated by position in the trial or by the ratio of target stimuli to non-target stimuli at different trial positions. fMRI-constrained source analysis revealed a temporal pattern of source activities starting in occipital and temporal brain regions, followed by a simultaneous engagement of parietal and frontal brain regions and a later activity of a source in pre-SMA (supplementary motor area). Source activities demonstrated a specific involvement of left fusiform gyrus in the non-target condition compared to the target condition that might be associated with mental imagination of the target stimulus during non-target probe processing. Source activities, furthermore, showed the anterior cingulate to be particularly involved in target processing compared to non-target processing before response execution and the pre-SMA before and during response execution. These brain areas appear to be activated in different stages of conflict managing operations due to a lower stimulus frequency of target trials compared to non-target trials at different target positions in the present design.

P300-based brain-computer interface (BCI) event-related potentials (ERPs): People with amyotrophic lateral sclerosis (ALS) vs. age-matched controls

ObjectiveBrain-computer interfaces (BCIs) aimed at restoring communication to people with severe neuromuscular disabilities often use event-related potentials (ERPs) in scalp-recorded EEG activity. Up to the present, most research and development in this area has been done in the laboratory with young healthy control subjects. In order to facilitate the development of BCI most useful to people with disabilities, the present study set out to: (1) determine whether people with amyotrophic lateral sclerosis (ALS) and healthy, age-matched volunteers (HVs) differ in the speed and accuracy of their ERP-based BCI use; (2) compare the ERP characteristics of these two groups; and (3) identify ERP-related factors that might enable improvement in BCI performance for people with disabilities. MethodsSixteen EEG channels were recorded while people with ALS or healthy age-matched volunteers (HVs) used a P300-based BCI. The subjects with ALS had little or no remaining useful motor control (mean ALS Functional Rating Scale-Revised 9.4 (±9.5SD) (range 0–25)). Each subject attended to a target item as the items in a 6×6 visual matrix flashed. The BCI used a stepwise linear discriminant function (SWLDA) to determine the item the user wished to select (i.e., the target item). Offline analyses assessed the latencies, amplitudes, and locations of ERPs to the target and non-target items for people with ALS and age-matched control subjects. ResultsBCI accuracy and communication rate did not differ significantly between ALS users and HVs. Although ERP morphology was similar for the two groups, their target ERPs differed significantly in the location and amplitude of the late positivity (P300), the amplitude of the early negativity (N200), and the latency of the late negativity (LN). ConclusionsThe differences in target ERP components between people with ALS and age-matched HVs are consistent with the growing recognition that ALS may affect cortical function. The development of BCIs for use by this population may begin with studies in HVs but also needs to include studies in people with ALS. Their differences in ERP components may affect the selection of electrode montages, and might also affect the selection of presentation parameters (e.g., matrix design, stimulation rate). SignificanceP300-based BCI performance in people severely disabled by ALS is similar to that of age-matched control subjects. At the same time, their ERP components differ to some degree from those of controls. Attention to these differences could contribute to the development of BCIs useful to those with ALS and possibly to others with severe neuromuscular disabilities.