All in Good Time: Long-Lasting Postdictive Effects Reveal Discrete Perception

Herzog, Michael H.; Drissi-Daoudi, Leila; Doerig, Adrien

doi:10.1016/j.tics.2020.07.001

Cited by 64 publications

(78 citation statements)

References 93 publications

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“…While phenomenal consciousness appears continuous (imagine watching someone walk across your field of vision or hearing a melody), it appears so despite the fact that we only have access to individual moments of time at any given instant. Scientific theories of this kind of conscious awareness generally involve formal models that propose varying degrees and stages of non-conscious processing preceding conscious awareness ( Herzog et al, 2020 ). These theories involving conscious perception are tested in experimental paradigms such as the attentional blink task, which demonstrates that varying the duration of extremely rapid presentation of stimuli can reveal differentiable non-conscious and conscious perception processes ( Sergent et al, 2005 ).…”

Section: The Subjective Effects Of Psychedelics and The Easy Problems Of Consciousnessmentioning

confidence: 99%

Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

Yaden

Johnson

Griffiths

et al. 2021

International Journal of Neuropsychopharmacology

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Psychedelic substances produce unusual and compelling changes in conscious experience which have prompted some to propose that psychedelics may provide unique insights explaining the nature of consciousness. At present, psychedelics, like other current scientific tools and methods, seem unlikely to provide information relevant to the so-called “hard problem of consciousness,” which involves explaining how first-person experience can emerge. However, psychedelics bear on multiple “easy problems of consciousness,” which involve relations between subjectivity, brain function, and behavior. In this review, we discuss common meanings of the term "consciousness" when used with regard to psychedelics and consider some models of the effects of psychedelics on the brain that have also been associated with explanatory claims about consciousness. We conclude by calling for epistemic humility regarding the potential for psychedelic research to aid in explaining the hard problem of consciousness while pointing to ways in which psychedelics may advance the study of many specific aspects of consciousness.

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Section: The Subjective Effects Of Psychedelics and The Easy Problems Of Consciousnessmentioning

confidence: 99%

Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

Yaden

Johnson

Griffiths

et al. 2021

International Journal of Neuropsychopharmacology

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“…The temporal dynamics of visual processing have led to the idea that visual perception may be described as a "discrete" process (Freeman, 2006;Herzog, Drissi-Daoudi, & Doerig, 2020;VanRullen, 2016;VanRullen & Koch, 2003). Evidence for this idea comes, for example, from the wagon wheel illusion -a wheel in movies or TV seemingly rotating backwards -which is supposed to occur when the "sampling rate" of visual processing and the temporal frequency of the stimulus are misaligned (VanRullen, Reddy, & Koch, 2005).…”

Section: An Active-vision Interpretation Of Preview Effectsmentioning

confidence: 99%

The extrafoveal preview paradigm as a measure of predictive, active sampling in visual perception

2021

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A key feature of visual processing in humans is the use of saccadic eye movements to look around the environment. Saccades are typically used to bring relevant information, which is glimpsed with extrafoveal vision, into the high-resolution fovea for further processing. With the exception of some unusual circumstances, such as the first fixation when walking into a room, our saccades are mainly guided based on this extrafoveal preview. In contrast, the majority of experimental studies in vision science have investigated "passive" behavioral and neural responses to suddenly appearing and often temporally or spatially unpredictable stimuli. As reviewed here, a growing number of studies have investigated visual processing of objects under more natural viewing conditions in which observers move their eyes to a stationary stimulus, visible previously in extrafoveal vision, during each trial. These studies demonstrate that the extrafoveal preview has a profound influence on visual processing of objects, both for behavior and neural activity. Starting from the preview effect in reading research we follow subsequent developments in vision research more generally and finally argue that taking such evidence seriously leads to a reconceptualization of the nature of human visual perception that incorporates the strong influence of prediction and action on sensory processing. We review theoretical perspectives on visual perception under naturalistic viewing conditions, including theories of active vision, active sensing, and sampling. Although the extrafoveal preview paradigm has already provided useful information about the timing of, and potential mechanisms for, the close interaction of the oculomotor and visual systems while reading and in natural scenes, the findings thus far also raise many new questions for future research.

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“…White, 2018). Vision appears continuous to introspection, yet a number of perceptual phenomena are difficult to reconcile with a continuously updating perceptual process (Herzog et al, 2020; Sokoliuk & VanRullen, 2019). The flash-lag effect and the Fröhlich effect are two such examples.…”

Section: Introductionmentioning

confidence: 99%

“…The Fröhlich illusion refers to the observation that the onset of a moving stimulus is often mislocalized as being further along the trajectory of motion than it really is (Fröhlich, 1923; Kerzel, 2010). Many variants of discrete sampling models have been proposed (for reviews, see: Herzog et al, 2020; VanRullen, 2016; P. A. White, 2018), but recently Schneider (2018) proposed a unifying account of both the flash-lag and Fröhlich illusions based on discrete sampling.…”

Section: Introductionmentioning

confidence: 99%

No Evidence for a Single Oscillator Underlying Discrete Visual Percepts

Morrow

Samaha

2021

Preprint

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Theories of perception based on discrete sampling posit that visual consciousness is reconstructed based on snapshot-like perceptual moments, as opposed to being updated continuously. According to a model proposed by Schneider (2018), discrete sampling can explain both the flash-lag and the Fröhlich illusion, whereby a lag in the conscious updating of a moving stimulus alters its perceived spatial location in comparison to a stationary stimulus. The alpha-band frequency, which is associated with phasic modulation of stimulus detection and the temporal resolution of perception, has been proposed to reflect the duration of perceptual moments. The goal of this study was to determine whether a single oscillator (e.g., alpha) is underlying the duration of perceptual moments, which would predict that the point of subjective equality (PSE) in the flash-lag and Fröhlich illusions are positively correlated across individuals. Although our displays induced robust flash-lag and Fröhlich effects, virtually zero correlation was seen between the PSE in the two illusions, indicating that the illusion magnitudes are unrelated across observers. These findings suggest that, if discrete sampling theory is true, these illusory percepts either rely on different oscillatory frequencies or not on oscillations at all. Alternatively, discrete sampling may not be the mechanism underlying these two motion illusions or our methods were ill-suited to test the theory.

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All in Good Time: Long-Lasting Postdictive Effects Reveal Discrete Perception

Cited by 64 publications

References 93 publications

Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

The extrafoveal preview paradigm as a measure of predictive, active sampling in visual perception

No Evidence for a Single Oscillator Underlying Discrete Visual Percepts

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