scholarly journals Visual processing: conscious until proven otherwise

2018 ◽  
Vol 5 (1) ◽  
pp. 171783 ◽  
Author(s):  
Tarryn Balsdon ◽  
Colin W. G. Clifford
Keyword(s):  
Response Bias ◽  
Visual Processing ◽  
Unconscious Perception ◽  
Unconscious Processing ◽  
Task Differences ◽  
Phenomenal Awareness ◽  
Perceptual Evidence ◽  
Pattern Of Performance ◽  
Proportion Correct

Unconscious perception, or perception without awareness, describes a situation where an observer's behaviour is influenced by a stimulus of which they have no phenomenal awareness. Perception without awareness is often claimed on the basis of a difference in thresholds for tasks that do and do not require awareness, for example, detecting the stimulus (requiring awareness) and making accurate judgements about the stimulus (based on unconscious processing). Although a difference in thresholds would be expected if perceptual evidence were processed without awareness, such a difference does not necessitate that this is actually occurring: a difference in thresholds can also arise from response bias, or through task differences. Here we ask instead whether the pattern of performance could be obtained if the observer were aware of the evidence used in making their decisions. A backwards masking paradigm was designed using digits as target stimuli, with difficulty controlled by the time between target and mask. Performance was measured over three tasks: detection, graphic discrimination and semantic discrimination. Despite finding significant differences in thresholds measured using proportion correct, and in observer sensitivity, modelling suggests that these differences were not the result of perception without awareness. That is, the observer was not relying solely on unconscious information to make decisions.

Invisible Adaptation: The Effect of Awareness on the Strength of the Motion Aftereffect

Perception ◽  
2020 ◽  
Vol 49 (8) ◽  
pp. 835-857
Author(s):  
Daphne Roumani ◽  
Konstantinos Moutoussis
Keyword(s):  
Visual Processing ◽  
Discrimination Task ◽  
Motion Aftereffect ◽  
Stimulus Strength ◽  
Perceptual Awareness ◽  
Physical Stimulus ◽  
Adaptation Stimulus ◽  
Unconscious Processing ◽  
Total Absence ◽  
Direction Discrimination

The ability to process information despite the lack of perceptual awareness is one of the most fascinating aspects of the visual system. Such unconscious processing is often investigated using adaptation, where any presence of the former can be traced by its footprint on aftereffects following the latter. We have investigated the mechanisms of the motion aftereffect (MAE) using random dot displays of varying motion coherence as well as crowding to modulate both the physical as well as the perceptual strength of the adaptation stimulus. Perceptual strength was quantitatively measured as the performance in a forced-choice direction-discrimination task. A motion-nulling technique was used to quantitatively measure the strength of the MAE. We show that the strength of the dynamic MAE is independently influenced by both the physical stimulus strength as well as the subjective perceptual strength, with the effect of the former being more prominent than that of the latter. We further show that the MAE still persists under conditions of subthreshold perception. Our results suggest that perceptual awareness can influence the strength of visual processing, but the latter is not fully dependent on the former and can still take place at its partial or even total absence.

scholarly journals Perceptual restoration fails to recover unconscious processing for smooth eye movements after occipital stroke

2021 ◽  
Author(s):  
Sunwoo Kwon ◽  
Krystel R. Huxlin ◽  
Jude F. Mitchell
Keyword(s):  
Visual Cortex ◽  
Eye Movements ◽  
Visual System ◽  
Motion Perception ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Conscious Perception ◽  
Stroke Patients ◽  
The Unconscious ◽  
Unconscious Processing

AbstractVisual pathways that guide actions do not necessarily mediate conscious perception. Patients with primary visual cortex (V1) damage lose conscious perception but often retain unconscious abilities (e.g. blindsight). Here, we asked if saccade accuracy and post-saccadic following responses (PFRs) that automatically track target motion upon saccade landing are retained when conscious perception is lost. We contrasted these behaviors in the blind and intact fields of 8 chronic V1-stroke patients, and in 8 visually-intact controls. Saccade accuracy was relatively normal in all cases. Stroke patients also had normal PFR in their intact fields, but no PFR in their blind fields. Thus, V1 damage did not spare the unconscious visual processing necessary for automatic, post-saccadic smooth eye movements. Importantly, visual training that recovered motion perception in the blind field did not restore the PFR, suggesting a clear dissociation between pathways mediating perceptual restoration and automatic actions in the V1-damaged visual system.

scholarly journals Consciousness, Introspection, and Subjective Measures

2020 ◽  
pp. 609-634
Author(s):  
Maja Spener
Keyword(s):  
Response Bias ◽  
Research Area ◽  
Unconscious Perception ◽  
Subjective Measures ◽  
The Subject ◽  
Present Response

In recent years, the divide between conscious and unconscious perception has been the focus of a thriving research area in the science of consciousness. Subjective measures, frequently referred to as ‘introspective measures’, play a prominent role in this literature and have been the subject of intense criticism. This chapter discusses the main types of subjective measures used in current-day science of consciousness. I explain the key worry about such measures, namely the problem of a putatively ever-present response bias. I then turn to the question of whether subjective measures of consciousness are introspective. I show that there is no clear answer to this question, as proponents of subjective measures do not employ a worked out notion of subjective access. In turn, as I explain, this makes the problem of response bias less tractable than it might otherwise be.

scholarly journals Mechanisms Underlying Unconscious Processing and Their Alterations in Post-traumatic Stress Disorder: Neuroimaging of Zero Monetary Outcomes Contextually Framed as “No Losses” vs. “No Gains”

2020 ◽  
Vol 14 ◽  
Author(s):  
Igor Elman ◽  
Jaymin Upadhyay ◽  
Steven Lowen ◽  
Keerthana Karunakaran ◽  
Mark Albanese ◽  
...  
Keyword(s):  
Post Traumatic Stress Disorder ◽  
Traumatic Stress ◽  
Visual Processing ◽  
Stress Disorder ◽  
Post Traumatic Stress ◽  
Unconscious Processing ◽  
Clinical Observations ◽  
Dorsolateral Prefrontal ◽  
Post Traumatic ◽  
Healthy Participants

Although unconscious processing is a key element of mental operation, its neural correlates have not been established. Also, clinical observations suggest that unconscious processing may be involved in the pathophysiology of post-traumatic stress disorder (PTSD), but the neurobiological mechanisms underlying such impairments remain unknown. The purpose of the present study was to examine putative mechanisms underlying unconscious processing by healthy participants and to determine whether these mechanisms may be altered in PTSD patients. Twenty patients with PTSD and 27 healthy individuals were administered a validated wheel of fortune-type gambling task during functional magnetic resonance imaging (fMRI). Unconscious processing was elicited using unconscious contextual framing of the zero monetary outcomes as “no loss,” “no gain” or as “neutral.” Brief passive visual processing of the “no loss” vs. “no gain” contrast by healthy participants yielded bilateral frontal-, temporal- and insular cortices and striatal activations. Between-group comparison revealed smaller activity in the left anterior prefrontal-, left dorsolateral prefrontal-, right temporal- and right insular cortices and in bilateral striatum in PTSD patients with the left dorsolateral prefrontal cortex activity been more pronounced in those with greater PTSD severity. These observations implicate frontal-, temporal-, and insular cortices along with the striatum in the putative mechanisms underlying unconscious processing of the monetary outcomes. Additionally, our results support the hypothesis that PTSD is associated with primary cortical and subcortical alterations involved in the above processes and that these alterations may be related to some aspects of PTSD symptomatology.

Consciousness for perception and for action: A perspective from unconscious binding

2016 ◽  
Vol 39 ◽  
Author(s):  
Zhicheng Lin
Keyword(s):  
Unconscious Perception ◽  
Unconscious Processing ◽  
Focal Attention

AbstractI argue that the scope and strength of unconscious perception have been overestimated in extant theories. I describe an unconscious binding perspective, and how in conjunction with rigorous methodology it can guide the delineation of unconscious processing. Under this perspective, the function of consciousness is to increase the saliency of conscious contents by facilitating the deployment of focal attention.

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

Picture Recognition Errors in the Differential Diagnosis of Alzheimer’s Disease

2019 ◽  
Vol 30 (3) ◽  
pp. 157-168
Author(s):  
Helmut Hildebrandt ◽  
Jana Schill ◽  
Jana Bördgen ◽  
Andreas Kastrup ◽  
Paul Eling
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Differential Diagnosis ◽  
Clinical Diagnosis ◽  
Response Bias ◽  
Recognition Task ◽  
Discriminatory Power ◽  
False Alarms ◽  
Picture Recognition ◽  
Recognition Errors

Abstract. This article explores the possibility of differentiating between patients suffering from Alzheimer’s disease (AD) and patients with other kinds of dementia by focusing on false alarms (FAs) on a picture recognition task (PRT). In Study 1, we compared AD and non-AD patients on the PRT and found that FAs discriminate well between these groups. Study 2 served to improve the discriminatory power of the FA score on the picture recognition task by adding associated pairs. Here, too, the FA score differentiated well between AD and non-AD patients, though the discriminatory power did not improve. The findings suggest that AD patients show a liberal response bias. Taken together, these studies suggest that FAs in picture recognition are of major importance for the clinical diagnosis of AD.

The Persnickety Pervasiveness of Rating Enhancement in Personality Assessment

2020 ◽  
pp. 1-13
Author(s):  
Alicia A. Stachowski ◽  
John T. Kulas
Keyword(s):  
Response Bias ◽  
Personality Assessment ◽  
Current Paper ◽  
Psychological Measurement ◽  
Shared Sets ◽  
Self Reports ◽  
Original Target ◽  
Target Profile ◽  
Do So ◽  
Normative Influences

Abstract. The current paper explores whether self and observer reports of personality are properly viewed through a contrasting lens (as opposed to a more consonant framework). Specifically, we challenge the assumption that self-reports are more susceptible to certain forms of response bias than are informant reports. We do so by examining whether selves and observers are similarly or differently drawn to socially desirable and/or normative influences in personality assessment. Targets rated their own personalities and recommended another person to also do so along shared sets of items diversely contaminated with socially desirable content. The recommended informant then invited a third individual to additionally make ratings of the original target. Profile correlations, analysis of variances (ANOVAs), and simple patterns of agreement/disagreement consistently converged on a strong normative effect paralleling item desirability, with all three rater types exhibiting a tendency to reject socially undesirable descriptors while also endorsing desirable indicators. These tendencies were, in fact, more prominent for informants than they were for self-raters. In their entirety, our results provide a note of caution regarding the strategy of using non-self informants as a comforting comparative benchmark within psychological measurement applications.

Detection of Malingered Neurocognitive Dysfunction Among Patients with Acquired Brain Injuries

2013 ◽  
Vol 29 (4) ◽  
pp. 253-262 ◽  
Author(s):  
Omer Hegedish ◽  
Dan Hoofien
Keyword(s):  
Response Bias ◽  
Concurrent Validity ◽  
Convergent Validity ◽  
Brain Injuries ◽  
Neurocognitive Dysfunction ◽  
Word Memory Test ◽  
Malingered Neurocognitive Dysfunction ◽  
Compensation Seeking ◽  
Seeking Behavior ◽  
Verbal Test

The Word Memory Test (WMT) is one of the most sensitive forced-choice tests available designed to evaluate negative response bias (NRB). Presently there is no valid verbal test designed to evaluate NRB for Hebrew-speaking patients. The aims of the present study were to validate the response bias measures of the WMT among Hebrew-speaking patients with acquired brain injuries and to reveal the malingering base rate among Israeli patients involved in compensation-seeking. Participants were 112 patients. The Test of Memory Malingering (TOMM) was used for convergent validity and injury related variables were used for concurrent validity. A translated version of the WMT had high split-half reliability. Regarding convergent validity, WMT effort measures had high positive correlations with the TOMM. Moreover, based on TOMM cutoff scores for classification, the WMT had reasonable classification rates. Regarding concurrent validity, multivariate logistic regression revealed that failure in the WMT was significantly predicted by normal brainscans and involvement in compensation-seeking behavior. The baserate of probable malingering was 34%. These findings emphasize the universality of the WMT in detecting NRB and establishing a malingered neurocognitive dysfunction baserate among Israeli patients involved in compensation-seeking.

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