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Full-Text Articles in Cognition and Perception
Measuring Perceptual Consciousness, Marjan Persuh
Measuring Perceptual Consciousness, Marjan Persuh
Publications and Research
Conscious perception is typically assessed with either objective or subjective measures (Seth et al.,2008). Measures are considered objective if conscious perception is estimated from performancein a discrimination task; inability to discriminate between stimuli is taken as evidence thatparticipants had no conscious perception (Hannula et al., 2005). Measures are considered subjectiveif participants report their visual experience on each trial (Sergent and Dehaene, 2004; Del Culet al., 2007). One type of subjective measures consists of metacognitivejudgments; the relationshipbetween metacognition and perceptual awareness is a matter ofdebate (Fleming and Lau, 2014;Jachs et al., 2015) and I will not discuss these measures further. Likewise, …
Barack Obama Blindness (Bob): Absence Of Visual Awareness To A Single Object, Marjan Persuh, Robert D. Melara
Barack Obama Blindness (Bob): Absence Of Visual Awareness To A Single Object, Marjan Persuh, Robert D. Melara
Publications and Research
In two experiments, we evaluated whether a perceiver’s prior expectations could alone obliterate his or her awareness of a salient visual stimulus. To establish expectancy, observers first made a demanding visual discrimination on each of three baseline trials. Then, on a fourth, critical trial, a single, salient and highly visible object appeared in full view at the center of the visual field and in the absence of any competing visual input. Surprisingly, fully half of the participants were unaware of the solitary object in front of their eyes. Dramatically, observers were blind even when the only stimulus on display was …
Direct Control Of Visual Perception With Phase-Specific Modulation Of Posterior Parietal Cortex, Andrew Jaegle, Tony Ro
Direct Control Of Visual Perception With Phase-Specific Modulation Of Posterior Parietal Cortex, Andrew Jaegle, Tony Ro
Publications and Research
We examined the causal relationship between the phase of alpha oscillations (9–12 Hz) and conscious visual perception using rhythmic TMS (rTMS) while simultaneously recording EEG activity. rTMS of posterior parietal cortex at an alpha frequency (10 Hz), but not occipital or sham rTMS, both entrained the phase of subsequent alpha oscillatory activity and produced a phase-dependent change on subsequent visual perception, with lower discrimination accuracy for targets presented at one phase of the alpha oscillatory waveform than for targets presented at the opposite phase. By extrinsically manipulating the phase of alpha before stimulus presentation, we provide direct evidence that the …