Introspective agents can recognize the extent to which their internal perceptual experiences deviate from the actual states of the external world. This ability, also known as insight, is critically ...required for reality testing and is impaired in psychosis, yet little is known about its cognitive underpinnings. We develop a Bayesian modeling framework and a psychophysics paradigm to quantitatively characterize this type of insight while people experience a motion after-effect illusion. People can incorporate knowledge about the illusion into their decisions when judging the actual direction of a motion stimulus, compensating for the illusion (and often overcompensating). Furthermore, confidence, reaction-time, and pupil-dilation data all show signatures consistent with inferential adjustments in the Bayesian insight model. Our results suggest that people can question the veracity of what they see by making insightful inferences that incorporate introspective knowledge about internal distortions.
A distinction has recently been drawn between surface distortions and deep distortions in false memory, where the former are conventional errors of commission and the latter are illogical relations ...among multiple memories of items. The deep distortions that have been studied to date are violations of the logical rules that govern incompatibility relations, such as additivity and countable additivity. Because that work is confined to laboratory word-list tasks, it is subject to the ecological validity criticism that memory for everyday facts may not exhibit such phenomena. We report evidence that memory for everyday facts displays the same deep distortions as laboratory tasks. We developed a version of the conjoint-recognition paradigm that measures memory for incompatible general knowledge facts, similar to those found on the quiz program Jeopardy! In experiments with university participants, four deep distortions were detected (violations of the additivity, countable additivity, universal set, and compensation rules), with participants consistently remembering more than what is logically possible. The distortions were more robust than in laboratory experiments, and memories of incompatible facts (e.g., Jupiter and Saturn cannot both be the largest planet in the solar system) did not suppress each other. These patterns were replicated in subsequent experiments with older and more diverse participant samples. Consistent with the notion that deep distortions are by-products of gist memory, conjoint-recognition modeling analyses revealed that memory for everyday facts was even more reliant on gist than memory for word lists, and that verbatim memory was near-floor.
Public Significance Statement
When events are physically incompatible, they obey some inviolate logical constraints: You cannot simultaneously stand on your head and on your feet, nor can you simultaneously turn left and turn right when you arrive at an intersection. Do our memories of incompatible events obey these logical rules? Fuzzy-trace theory predicts that the answer is no because reliance on semantic gist causes events to be over remembered. That prediction has been confirmed in laboratory word-list experiments, but does it hold for real-world memories of meaningful facts? We investigated this question in memory for everyday facts that appear on quiz programs such as Jeopardy! Logical rules such as additivity, countable additivity, universal event, and compensation were all violated by wide margins-the reason being that memory was even more reliant on semantic gist than in word-list experiments.
Peripheral vision is fundamentally limited not by the visibility of features, but by the spacing between them 1. When too close together, visual features can become “crowded” and perceptually ...indistinguishable. Crowding interferes with basic tasks such as letter and face identification and thus informs our understanding of object recognition breakdown in peripheral vision 2. Multiple proposals have attempted to explain crowding 3, and each is supported by compelling psychophysical and neuroimaging data 4–6 that are incompatible with competing proposals. In general, perceptual failures have variously been attributed to the averaging of nearby visual signals 7–10, confusion between target and distractor elements 11, 12, and a limited resolution of visual spatial attention 13. Here we introduce a psychophysical paradigm that allows systematic study of crowded perception within the orientation domain, and we present a unifying computational model of crowding phenomena that reconciles conflicting explanations. Our results show that our single measure produces a variety of perceptual errors that are reported across the crowding literature. Critically, a simple model of the responses of populations of orientation-selective visual neurons accurately predicts all perceptual errors. We thus provide a unifying mechanistic explanation for orientation crowding in peripheral vision. Our simple model accounts for several perceptual phenomena produced by crowding of orientation and raises the possibility that multiple classes of object recognition failures in peripheral vision can be accounted for by a single mechanism.
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•An object surrounded by distractors is unrecognizable in peripheral vision•We provide a novel method to systematically study such “crowded” perception•A simple population code model produces the diverse errors made by human observers•A single mechanism may thus suffice to explain multiple classes of crowding
Harrison and Bex studied visual “crowding,” when objects that are too close together become perceptually indistinguishable; their results suggest that a biologically inspired model of a population of neurons can account for this breakdown of visual awareness in peripheral vision.
I report an illusion in which individuals experience that they are located outside their physical bodies and looking at their bodies from this perspective. This demonstrates that the experience of ...being localized within the physical body can be determined by the visual perspective in conjunction with correlated multisensory information from the body.
Recent studies have shown the presence of distortions in proprioceptive hand localization tasks. Those results were interpreted as reflecting specific perceptual distortions bound to a body model. It ...was especially suggested that hand distortions could be related to distortions of somatotopic cortical maps. In this study, we show that hand distortions measured in localization tasks might be partly driven by a general false belief about hand landmark locations (conceptual biases). We especially demonstrate that hand and object distortions are present in similar magnitude when correcting for the conceptual bias of the knuckles (Experiment 1) or when asking participants to directly locate spatially well-represented landmarks (i.e., without conceptual biases) on their hand (Experiment 2). Altogether our results suggest that localization task distortions are nonspecific to the body and that similar perceptual distortions could underlie localization performance measured on objects and hands.
Public Significance Statement
The present study suggests that distortion differences between one's hand and objects measured in body model localization tasks are more likely to be explained by inaccurate knowledge about hand landmarks than somatosensory distortions. Correcting for this inaccurate knowledge or using a better known configuration of hand landmarks led to a similar magnitude of distortions between hand and objects. Our results confirm the idea that localization task distortions involving nondirect somatosensory stimulations are nonspecific to the body and that similar perceptual distortions might underlie localization performance for hands and objects.
Humans normally experience the conscious self as localized within their bodily borders. This spatial unity may break down in certain neurological conditions such as out-of-body experiences, leading ...to a striking disturbance of bodily self-consciousness. On the basis of these clinical data, we designed an experiment that uses conflicting visual-somatosensory input in virtual reality to disrupt the spatial unity between the self and the body. We found that during multisensory conflict, participants felt as if a virtual body seen in front of them was their own body and mislocalized themselves toward the virtual body, to a position outside their bodily borders. Our results indicate that spatial unity and bodily self-consciousness can be studied experimentally and are based on multisensory and cognitive processing of bodily information.
Phantom sensations and sensory hypersensitivity are disordered perceptions that characterize a variety of intractable conditions involving the somatosensory, visual, and auditory modalities. We ...report physiological correlates of two perceptual abnormalities in the auditory domain: tinnitus, the phantom perception of sound, and hyperacusis, a decreased tolerance of sound based on loudness. Here, subjects with and without tinnitus, all with clinically normal hearing thresholds, underwent 1) behavioral testing to assess sound-level tolerance and 2) functional MRI to measure sound-evoked activation of central auditory centers. Despite receiving identical sound stimulation levels, subjects with diminished sound-level tolerance (i.e., hyperacusis) showed elevated activation in the auditory midbrain, thalamus, and primary auditory cortex compared with subjects with normal tolerance. Primary auditory cortex, but not subcortical centers, showed elevated activation specifically related to tinnitus. The results directly link hyperacusis and tinnitus to hyperactivity within the central auditory system. We hypothesize that the tinnitus-related elevations in cortical activation may reflect undue attention drawn to the auditory domain, an interpretation consistent with the lack of tinnitus-related effects subcortically where activation is less potently modulated by attentional state. The data strengthen, at a mechanistic level, analogies drawn previously between tinnitus/hyperacusis and other, nonauditory disordered perceptions thought to arise from neural hyperactivity such as chronic neuropathic pain and photophobia.
A tidal wave of recent research purports to have discovered that higher-level states such as moods, action capabilities, and categorical knowledge can literally and directly affect how things look. ...Are these truly effects on perception, or might some instead reflect influences on judgment, memory, or response bias? Here, we exploited an infamous art-historical reasoning error (the so-called "El Greco fallacy") to demonstrate that multiple alleged top-down effects (including effects of morality on lightness perception and effects of action capabilities on spatial perception) cannot truly be effects on perception. We suggest that this error may also contaminate several other varieties of top-down effects and that this discovery has implications for debates over the continuity (or lack thereof) of perception and cognition.
•Strange face illusions are commonly experienced when fixating on face stimuli for prolonged periods under low light levels.•Strange face illusions involve either the perception of distorting facial ...features on the actual face being observed or the perception of completely new strange faces.•Illusions of new faces show a mean prevalence rate of 58% in healthy participants.•Age and gender are positively related to prevalence rates, with more new faces reported by samples of older individuals and those with more female participants.•Somekey areas of methodological concern were apparent in the studies, relating to small unjustified sample sizes, a lack of preregistration and providing conclusions and interpretations that do not seem to be justified by results.•Future research should aim to examine how the behavioural and environmental components of this paradigm combine to result in illusory faces and explain why illusions are more prevalent when gazing at others compared to self-reflections.
Strange face illusions describe a range of visual apparitions that occur when an observer gazes at their image reflected in a mirror or at another person’s face in a dimly lit room. The illusory effects range from mild alterations in colour, or contrast, to the perception of distorted facial features, or new strange faces.The current review critically evaluates studies investigating strange face illusions, their methodological quality, and existing interpretations.
Searches conducted using Scopus, PubMed, ScienceDirect and the grey literature until June 2022 identified 21 studies (N = 1,132; healthy participants n = 1,042; clinical participants n = 90) meeting the inclusion criteria (i.e., providing new empirical evidence relating to strange face illusions). The total sample had a mean age of 28.3 years (SD = 10.31) and two thirds (67 %) of participants tested to date are female. Results are reported using the Preferred Reporting Items for Systematic Reviews and meta-Analyses (PRISMA) guidelines. The review was preregistered at the Open Science Framework (OSF: https://osf.io/ek48d).
Pooling data across studies, illusory new strange faces are experienced by 58% (95%CI 48 to 68) of nonclinical participants. Study quality as assessed by the Appraisal Tool for Cross-Sectional Studies (AXIS) revealed that 3/21 (14.28%) studies were rated as high, 9/21 (42.86%) as moderate and 9/21 (42.86%) as low quality. Whilst the items relating specifically to reporting quality scored quite highly, those relating to study design and possible biases were lower and more variable. Overall, study quality accounted for 87% of the variance in reporting rates for strange faces, with higher quality being associated with lower illusion rates. The prevalence of illusions was also significantly greater in samples that were older, had higher proportions of female participants and for the interpersonal dyad (IGDT) compared to the mirror gaze paradigm (MGT). The moderating impact of study quality persisted in a multiple meta-regression involving participant age, paradigm type (IGDT vs MGT) and level of feature distortion. Our review point to the importance of reduced light levels, face stimuli and prolonged eye fixation for strange face illusions to emerge.
Strange face illusions reliably occur in both mirror-gazing and interpersonal gazing dyad paradigms. Further research of higher quality is required to establish the prevalence and particularly, the mechanisms underpinning strange face illusions.
Insomnia is prevalent, causing severe distress and impairment. This review focuses on illuminating the puzzling finding that many insomnia patients misperceive their sleep. They overestimate their ...sleep onset latency (SOL) and underestimate their total sleep time (TST), relative to objective measures. This tendency is ubiquitous (although not universal). Resolving this puzzle has clinical, theoretical, and public health importance. There are implications for assessment, definition, and treatment. Moreover, solving the puzzle creates an opportunity for real-world applications of theories from clinical, perceptual, and social psychology as well as neuroscience. Herein we evaluate 13 possible resolutions to the puzzle. Specifically, we consider the possible contribution, to misperception, of (1) features inherent to the context of sleep (e.g., darkness); (2) the definition of sleep onset, which may lack sensitivity for insomnia patients; (3) insomnia being an exaggerated sleep complaint; (4) psychological distress causing magnification; (5) a deficit in time estimation ability; (6) sleep being misperceived as wake; (7) worry and selective attention toward sleep-related threats; (8) a memory bias influenced by current symptoms and emotions, a confirmation bias/belief bias, or a recall bias linked to the intensity/recency of symptoms; (9) heightened physiological arousal; (10) elevated cortical arousal; (11) the presence of brief awakenings; (12) a fault in neuronal circuitry; and (13) there being 2 insomnia subtypes (one with and one without misperception). The best supported resolutions were misperception of sleep as wake, worry, and brief awakenings. A deficit in time estimation ability was not supported. We conclude by proposing several integrative solutions.
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