Introspection and subliminal perception

Ramsøy, Thomas Z.; Overgaard, Morten

doi:10.1023/b:phen.0000041900.30172.e8

Cited by 428 publications

(443 citation statements)

References 42 publications

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“…The confidence of detection was also reduced. This observation supports previous findings of the effects of TMS on target detection when applied to the primary visual cortex (11) and the effects on perceptual clarity when applied over the temporal lobe in a purely visual task (12,13).…”

Section: Tms Decreases the Ability To Identify The Target Arrow Figuressupporting

confidence: 91%

“…Simple binary choices, where subjects only respond positively or negatively to whether they have perceived a visual stimulus, have proven not to capture the graded nature of visual perception. We therefore adopted a modified version of the perception awareness scale (12,13) in which subjects rate the clarity of their perceptual experience on an ordinal scale. Similar subjective measures of clarity have been used in patients (14), and it has proven to be a more indicative measure of perceptual clarity than strict dichotic measures (12,13).…”

mentioning

confidence: 99%

“…We therefore adopted a modified version of the perception awareness scale (12,13) in which subjects rate the clarity of their perceptual experience on an ordinal scale. Similar subjective measures of clarity have been used in patients (14), and it has proven to be a more indicative measure of perceptual clarity than strict dichotic measures (12,13). Therefore, to quantify the effect of TMS, one of four arrow-like figures was displayed as the second light.…”

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confidence: 99%

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Action-blindsight in healthy subjects after transcranial magnetic stimulation

Christensen

Kristiansen

Rowe

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Clinical cases of blindsight have shown that visually guided movements can be accomplished without conscious visual perception. Here, we show that blindsight can be induced in healthy subjects by using transcranial magnetic stimulation over the visual cortex. Transcranial magnetic stimulation blocked the conscious perception of a visual stimulus, but subjects still corrected an ongoing reaching movement in response to the stimulus. The data show that correction of reaching movements does not require conscious perception of a visual target stimulus, even in healthy people. Our results support previous results suggesting that an efference copy is involved in movement correction, and this mechanism seems to be consistent even for movement correction without perception.consciousness ͉ perception ͉ reaching ͉ efference copy

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Section: Tms Decreases the Ability To Identify The Target Arrow Figuressupporting

confidence: 91%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Action-blindsight in healthy subjects after transcranial magnetic stimulation

Christensen

Kristiansen

Rowe

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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“…They were instructed to indicate the Gabor's orientation (left or right), and then to indicate their subjective visibility of the Gabor with a "seen" or "guess" judgment (experiment 1) or a rating on the four-point, perceptual awareness scale (PAS; experiment 2). The PAS was used in the second experiment to assess awareness using a more fine-grained and established scale of subjective visibility (17). The…”

Section: Resultsmentioning

confidence: 99%

Top-down control of the phase of alpha-band oscillations as a mechanism for temporal prediction

Samaha

Bauer

Cimaroli

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

217

166

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The physiological state of the brain before an incoming stimulus has substantial consequences for subsequent behavior and neural processing. For example, the phase of ongoing posterior alpha-band oscillations (8–14 Hz) immediately before visual stimulation has been shown to predict perceptual outcomes and downstream neural activity. Although this phenomenon suggests that these oscillations may phasically route information through functional networks, many accounts treat these periodic effects as a consequence of ongoing activity that is independent of behavioral strategy. Here, we investigated whether alpha-band phase can be guided by top-down control in a temporal cueing task. When participants were provided with cues predictive of the moment of visual target onset, discrimination accuracy improved and targets were more frequently reported as consciously seen, relative to unpredictive cues. This effect was accompanied by a significant shift in the phase of alpha-band oscillations, before target onset, toward each participant’s optimal phase for stimulus discrimination. These findings provide direct evidence that forming predictions about when a stimulus will appear can bias the phase of ongoing alpha-band oscillations toward an optimal phase for visual processing, and may thus serve as a mechanism for the top-down control of visual processing guided by temporal predictions.

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“…The experiment contained 72 trials and lasted around 1 h. The different adaptors were presented in randomized order. In the invisible condition, participants were asked to indicate their subjective experience of the apparent motion adaptor (Ramsøy & Overgaard, 2004): they pressed a key from 1 to 4, corresponding respectively to ''no perceptual experience'', ''a brief glimpse'', ''an almost clear image'', or ''a perfectly clear image'' of apparent motion.…”

Section: Adaptation Phase Proceduresmentioning

confidence: 99%

Temporal structure coding with and without awareness

Faivre

Koch

2014

Cognition

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a b s t r a c tIn order to interpret a constantly changing environment, visual events far apart in space and time must be integrated into a unified percept. While spatial properties of invisible signals are known to be encoded without awareness, the fate of temporal properties remains largely unknown. Here, we probed temporal integration for two distinct motion stimuli that were either visible or rendered invisible using continuous flash suppression. We found that when invisible, both the direction of apparent motion and the gender of point-light walkers were processed only when defined across short time periods (i.e., respectively 100 ms and 1000 ms). This limitation was not observed under full visibility. These similar findings at two different hierarchical levels of processing suggest that temporal integration windows shrink in the absence of perceptual awareness. We discuss this phenomenon as a key prediction of the global neuronal workspace and the information integration theories of consciousness.

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Introspection and subliminal perception

Cited by 428 publications

References 42 publications

Action-blindsight in healthy subjects after transcranial magnetic stimulation

Action-blindsight in healthy subjects after transcranial magnetic stimulation

Top-down control of the phase of alpha-band oscillations as a mechanism for temporal prediction

Temporal structure coding with and without awareness

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