scholarly journals Perceptual grouping constrains inhibition in time-based visual selection

2019 ◽  
Vol 82 (2) ◽  
pp. 500-517 ◽  
Author(s):  
Zorana Zupan ◽  
Derrick G. Watson
Keyword(s):  
Perceptual Grouping ◽  
Visual Selection ◽  
Selection Task ◽  
Selection Experiment ◽  
Preview Benefit ◽  
Capacity Limits ◽  
Complex Stimuli ◽  
Selective Processing ◽  
The Individual ◽  
Task Irrelevant

AbstractIn time-based visual selection, task-irrelevant, old stimuli can be inhibited in order to allow the selective processing of new stimuli that appear at a later point in time (the preview benefit; Watson & Humphreys, 1997). The current study investigated if illusory and non-illusory perceptual groups influence the ability to inhibit old and prioritize new stimuli in time-based visual selection. Experiment 1 showed that with Kanizsa-type illusory stimuli, a preview benefit occurred only when displays contained a small number of items. Experiment 2 demonstrated that a set of Kanizsa-type illusory stimuli could be selectively searched amongst a set of non-illusory distractors with no additional preview benefit obtained by separating the two sets of stimuli in time. Experiment 3 showed that, similarly to Experiment 1, non-illusory perceptual groups also produced a preview benefit only for a small number of number of distractors. Experiment 4 demonstrated that local changes to perceptually grouped old items eliminated the preview benefit. The results indicate that the preview benefit is reduced in capacity when applied to complex stimuli that require perceptual grouping, regardless of whether the grouped elements elicit illusory contours. Further, inhibition is applied at the level of grouped objects, rather than to the individual elements making up those groups. The findings are discussed in terms of capacity limits in the inhibition of old distractor stimuli when they consist of perceptual groups, the attentional requirements of forming perceptual groups and the mechanisms and efficiency of time-based visual selection.

The Subjective Present and Its Modulation in Clinical Contexts

2013 ◽  
Vol 1 (2) ◽  
pp. 239-259 ◽  
Author(s):  
Wolfgang Tschacher ◽  
Fabian Ramseyer ◽  
Claudia Bergomi
Keyword(s):  
Perceptual Grouping ◽  
Statistical Significance ◽  
Temporal Distribution ◽  
Future Research ◽  
Implicit Processes ◽  
The Social ◽  
Gestalt Perception ◽  
Psychotherapeutic Techniques ◽  
The Mean ◽  
The Individual

Time is a basic dimension in psychology, underlying behavior and experience. Timing and time perception constitute implicit processes that are often inaccessible to the individual person. Research in this field has shown that timing is involved in many areas of clinical significance. In the projects presented here, we combine timing with seemingly different fields of research, such as psychopathology, perceptual grouping, and embodied cognition. Focusing on the time scale of the subjective present, we report findings from three different clinical studies: (1) We studied perceived causality in schizophrenia patients, finding that perceptual grouping (‘binding’, ‘Gestalt formation’), which leads to visual causality perceptions, did not distinguish between patients and healthy controls. Patients however did integrate context (provided by the temporal distribution of auditory context stimuli) less into perceptions, in significant contrast to controls. This is consistent with reports of higher inaccuracy in schizophrenia patients’ temporal processing. (2) In a project on auditory Gestalt perception we investigated auditory perceptual grouping in schizophrenia patients. The mean dwell time was positively related to how much patients were prone to auditory hallucinations. Dwell times of auditory Gestalts may be regarded as operationalizations of the subjective present; findings thus suggested that patients with hallucinations had a shorter present. (3) The movement correlations of interacting individuals were used to study the non-verbal synchrony between therapist and patient in psychotherapy sessions. We operationalized the duration of an embodied ‘social present’ by the statistical significance of such associations, finding a window of roughly 5.7 seconds in conversing dyads. We discuss that temporal scales of nowness may be modifiable, e.g., by mindfulness. This yields promising goals for future research on timing in the clinical context: psychotherapeutic techniques may alter binding processes, hence the subjective present of individuals, and may affect the social present in therapeutic interactions.

scholarly journals A Decision Support System For Integration Of Vendor Selection Task

2011 ◽  
Vol 10 (1) ◽  
pp. 132 ◽  
Author(s):  
Raydel Tullous ◽  
Richard Lee Utecht
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Analytic Hierarchy Process ◽  
Support System ◽  
Selection Task ◽  
Vendor Selection ◽  
Analytic Hierarchy ◽  
Purchasing Decision ◽  
The Individual ◽  
Hierarchy Process

<span>The purpose of this paper is to illustrate the usefulness of a particular decision support system, the Analytic Hierarchy Process (AHP), for developing and implementing integrated procurement systems. The purchasing decision support system (PDSS) proposed in this paper provides each participant involved in the purchasing process with a procedure to communicate their preferences and the reasons for those preferences. All of the participants preferences may be aggregated to determine an overall preference, or in some cases, the results may simply be used to gain a better understanding of the values the individual place on various attributes.</span>

scholarly journals The Athlete’s Brain: Cross-Sectional Evidence for Neural Efficiency during Cycling Exercise

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Sebastian Ludyga ◽  
Thomas Gronwald ◽  
Kuno Hottenrott
Keyword(s):  
Maximal Oxygen Consumption ◽  
Cortical Function ◽  
Cross Sectional ◽  
Eyes Closed ◽  
Exercise Condition ◽  
Beta Power ◽  
Neural Efficiency ◽  
Alpha Beta ◽  
The Individual ◽  
Task Irrelevant

The “neural efficiency” hypothesis suggests that experts are characterized by a more efficient cortical function in cognitive tests. Although this hypothesis has been extended to a variety of movement-related tasks within the last years, it is unclear whether or not neural efficiency is present in cyclists performing endurance exercise. Therefore, this study examined brain cortical activity at rest and during exercise between cyclists of higher (HIGH;n=14; 55.6 ± 2.8 mL/min/kg) and lower (LOW;n=15; 46.4 ± 4.1 mL/min/kg) maximal oxygen consumption (VO2MAX). Male and female participants performed a graded exercise test with spirometry to assessVO2MAX. After 3 to 5 days, EEG was recorded at rest with eyes closed and during cycling at the individual anaerobic threshold over a 30 min period. Possible differences in alpha/beta ratio as well as alpha and beta power were investigated at frontal, central, and parietal sites. The statistical analysis revealed significant differences between groups (F=12.04;p=0.002), as the alpha/beta ratio was increased in HIGH compared to LOW in both the resting state (p≤0.018) and the exercise condition (p≤0.025). The present results indicate enhanced neural efficiency in subjects with highVO2MAX, possibly due to the inhibition of task-irrelevant cognitive processes.

scholarly journals Separation of multiple motor memories through implicit and explicit processes

2021 ◽  
Author(s):  
Gefen Dawidowicz ◽  
Yuval Shaine ◽  
Firas Mawase
Keyword(s):  
Explicit Learning ◽  
Contextual Cues ◽  
Implicit Processes ◽  
Motor Behaviors ◽  
Explicit Processes ◽  
Individual Contributions ◽  
The Individual ◽  
Dependent Learning ◽  
Implicit And Explicit ◽  
Task Irrelevant

Acquisition of multiple motor skills without interference is a remarkable ability in sport and daily life. During adaptation to opposing perturbations, a common paradigm to study this ability, each perturbation can be successfully learned when a dynamical contextual cue, such as a follow-through movement, is associated with the direction of the perturbation. It is still unclear, however, to what extent this context-dependent learning engages the cognitive strategy-based explicit process and the implicit process that occurs without conscious awareness. Here, we designed four reaching experiments to untangle the individual contributions of the explicit and implicit components while participants learned opposing visuomotor perturbations, with a second unperturbed follow-through movement that served as a contextual cue. In Exp. 1 we replicated previous adaptation results and showed that follow-through movements also allow learning for opposing visuomotor rotations. For one group of participants in Exp. 2 we isolated strategic explicit learning by inducing a 2-sec time delay between movement and end-point feedback, while for another group we isolated the implicit component using the task-irrelevant error-clamp paradigm, in which participants were firmly instructed to aim their reaches directly to the target. Our data showed that opposing perturbations could be fully learned by explicit strategies; but when strategy was restricted, distinct implicit processes contributed to learning. In Exp.3, we examined whether the learned motor behaviors are influenced by the disparity between the follow-through contexts. We found that the location of follow-through targets had little effect on total learning, yet it led to more instances in which participants failed to learn the task. In Exp. 4, we explored the generalization capability to untrained novel targets. Participants showed near-flat generalization of the implicit and explicit processes to adjacent targets. Overall, our results indicate that follow-through contextual cues influence activity of both implicit and explicit processes during separation of motor memories. Furthermore, the follow-through context might activate, in part, top-down cognitive factors that influence not only the dynamics of the explicit learning but also the implicit process.

scholarly journals Selective Attention in Inattentional Blindness: Selection is Specific but Suppression is Not

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Katherine Wood ◽  
Daniel J. Simons
Keyword(s):  
Selective Attention ◽  
Inattentional Blindness ◽  
The Other ◽  
Critical Trial ◽  
Unexpected Events ◽  
Process Thought ◽  
The Individual ◽  
Task Irrelevant ◽  
Constant Color ◽  
Individual Objects

When we selectively attend to one set of objects and ignore another, we often fail to notice unexpected events. The likelihood of noticing varies depending on the similarity of an unexpected object to other items in the display, a process thought to be controlled by the attention set that we create for the attended and ignored objects. It remains unclear, though, how attention sets are formed and structured. Do they enhance features of attended objects (“white”) and suppress features of ignored objects (“black”), or do they distinguish objects based on relations or categories (“darker” versus “lighter,” or “dark objects” versus “light objects”)? In previous work, these explanations are confounded; the objects would be partitioned into the same groups regardless the structure of the attention set. In the present three experiments, the attended or ignored set of objects was a constant color while the other set was variable. When people attended white and ignored a multicolored set of objects (Experiment 1), novel colors were suppressed just as much as display colors, suggesting nonselective filtering of nonwhite objects. When the color of one set of objects varied across displays but was constant within them (Experiments 2 and 3), we again found as much suppression for task-irrelevant and novel colors as for actively ignored ones. Whenever people ignored a set of objects that varied in color, they suppressed unexpected objects that matched the ignored colors and that differed from the actively ignored items on the critical trial. In contrast, when people attended a varying set, noticing was enhanced only for unexpected objects that matched the currently attended color. In this task, attentional filtering is category-based and did not depend on the features of the individual objects.

scholarly journals Spatial working memory representations in human cortex are robust to a task-irrelevant interrupting stimulus

2021 ◽  
Author(s):  
Kelvin Vu-Cheung ◽  
Edward F Ester ◽  
Thomas C Sprague
Keyword(s):  
Working Memory ◽  
Visual Information ◽  
Spatial Working Memory ◽  
Delay Period ◽  
Visual Signals ◽  
Reconstruction Technique ◽  
Behavioral Performance ◽  
Visual Responses ◽  
The Individual ◽  
Task Irrelevant

Visual working memory (WM) enables the maintenance and manipulation of information no longer accessible in the visual world. Previous research has identified spatial WM representations in activation patterns in visual, parietal, and frontal cortex. In natural vision, the period between the encoding of information into WM and the time when it is used to guide behavior (the delay period) is rarely "empty", as is the case in most of the above laboratory experiments. In naturalistic conditions, eye movements, movement of the individual, and events in the environment result in visual signals which may overwrite or impair the fidelity of WM representations, especially in early sensory cortices. Here, we evaluated the extent to which a brief, irrelevant interrupting visual stimulus presented during a spatial WM delay period impaired behavioral performance and WM representation fidelity assayed using an image reconstruction technique (inverted encoding model). On each trial, participants (both sexes) viewed two target dots and were immediately post-cued to remember the precise spatial position of one dot. On 50% of trials, a brief interrupter stimulus appeared. While we observed strong transient univariate visual responses to the distracter stimulus, we saw no change in reconstructed neural WM representations under distraction, nor a change in behavioral performance on a continuous recall task. This suggests that spatial WM representations may be particularly robust to interference from incoming task-irrelevant visual information, perhaps related to their role in guiding movements.

scholarly journals A Quantitative Explanation of Responses to Disparity-Defined Edges in Macaque V2

2009 ◽  
Vol 101 (2) ◽  
pp. 701-713 ◽  
Author(s):  
C. E. Bredfeldt ◽  
J. C. A. Read ◽  
B. G. Cumming
Keyword(s):  
Visual Cues ◽  
Binocular Disparity ◽  
Extended Model ◽  
Scene Segmentation ◽  
Simple Consequence ◽  
Complex Stimuli ◽  
Response Enhancement ◽  
The Individual ◽  
Convergence Model ◽  
Quantitative Explanation

Previous experiments have shown that V2 neurons respond to complex stimuli such as cyclopean edges (edges defined purely by binocular disparity), angles, and motion borders. It is currently unknown whether these responses are a simple consequence of converging inputs from a prior stage of processing (V1). Alternatively, they may identify edges in a way that is invariant across a range of visual cues defining the edge, in which case they could provide a neuronal substrate for scene segmentation. Here, we examine the ability of a simple feedforward model that combines two V1-like inputs to describe the responses of V2 neurons to cyclopean edges. A linear feedforward model was able to qualitatively reproduce the major patterns of response enhancement for cyclopean edges seen in V2. However, quantitative fitting revealed that this model usually predicts response suppression by some edge configurations and such suppression was rarely seen in the data. This problem was resolved by introducing a squaring nonlinearity at the output of the individual inputs prior to combination. The extended model produced extremely good fits to most of our data. We conclude that the responses of V2 neurons to complex stimuli such as cyclopean edges can be adequately explained by a simple convergence model and do not necessarily represent the development of sophisticated mechanisms that signal scene segmentation, although they probably constitute a step toward this goal.

scholarly journals Concealed identity information detection with pupillometry in rapid serial visual presentation

2021 ◽  
Author(s):  
Ivory Chen ◽  
Aytac Karabay ◽  
Sebastiaan Mathot ◽  
Howard Bowman ◽  
Elkan Akyurek
Keyword(s):  
Rapid Serial Visual Presentation ◽  
Visual Presentation ◽  
Concealed Information Test ◽  
Individual Level ◽  
Identity Information ◽  
Information Detection ◽  
The Individual ◽  
Task Irrelevant ◽  
Concealed Information ◽  
Further Development

The concealed information test (CIT) relies on bodily reactions to stimuli that are hidden in mind. However, people can use countermeasures, such as purposely focusing on irrelevant things, to confound the CIT. A new method designed to prevent the use of countermeasures, based on rapid serial visual presentation (RSVP), presents each stimulus on the fringe of awareness. Previous studies that used RSVP in combination with electroencephalography (EEG) showed that participants exhibit a clear reaction to their real first name, when they pretend to have a different name, even when they try to prevent such a reaction. Since EEG measures are not easily applicable outside the laboratory, we investigated here whether pupil size, which is easier to measure, is also able to detect concealed identity information. In our study, 31 participants were asked to adopt a fake name, and search for this name in an RSVP task, while their pupil sizes were recorded. Apart from this fake name, their real name and a control name also appeared in the task. We found that the pupil dilated more in response to the task-irrelevant real name, as compared to control names. However, while most participants showed this effect qualitatively, it was not statistically significant for most participants when analysed individually. Taken together, our results show that the current RSVP task with pupillometry can detect concealed identity information at a group level. Further development of the method is needed to create a valid and reliable concealed identity information detector at the individual level.

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