201. Act quickly, decide later: long-latency visual processing underlies perceptual decisions but not reflexive behavior
- Author
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Jacob Jolij, Timothy L. Hodgson, Simon van Gaal, Victor A. F. Lamme, H. Steven Scholte, Brein en Cognitie (Psychologie, FMG), Experimental Psychology, and Faculty of Behavioural and Social Sciences
- Subjects
Male ,C850 Cognitive Psychology ,TRANSCRANIAL MAGNETIC STIMULATION ,CORTEX ,Unconscious mind ,Adolescent ,Cognitive Neuroscience ,media_common.quotation_subject ,medicine.medical_treatment ,Visual Physiology ,Stimulus (physiology) ,DISTINCT MODES ,Choice Behavior ,050105 experimental psychology ,Visual processing ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Perception ,RECURRENT NETWORK ARCHITECTURE ,Reaction Time ,medicine ,Humans ,0501 psychology and cognitive sciences ,Evoked potential ,10. No inequality ,media_common ,NATURAL IMAGES ,FEEDFORWARD ,05 social sciences ,MONKEY ,ATTENTION ,C830 Experimental Psychology ,FIGURE-GROUND SEGREGATION ,Transcranial magnetic stimulation ,SCENE SEGMENTATION ,Visual Perception ,Evoked Potentials, Visual ,Female ,Antisaccade task ,Psychology ,Photic Stimulation ,Psychomotor Performance ,030217 neurology & neurosurgery ,Cognitive psychology - Abstract
Humans largely guide their behavior by their visual representation of the world. Recent studies have shown that visual information can trigger behavior within 150 msec, suggesting that visually guided responses to external events, in fact, precede conscious awareness of those events. However, is such a view correct? By using a texture discrimination task, we show that the brain relies on long-latency visual processing in order to guide perceptual decisions. Decreasing stimulus saliency leads to selective changes in long-latency visually evoked potential components reflecting scene segmentation. These latency changes are accompanied by almost equal changes in simple RTs and points of subjective simultaneity. Furthermore, we find a strong correlation between individual RTs and the latencies of scene segmentation related components in the visually evoked potentials, showing that the processes underlying these late brain potentials are critical in triggering a response. However, using the same texture stimuli in an antisaccade task, we found that reflexive, but erroneous, prosaccades, but not antisaccades, can be triggered by earlier visual processes. In other words: The brain can act quickly, but decides late. Differences between our study and earlier findings suggesting that action precedes conscious awareness can be explained by assuming that task demands determine whether a fast and unconscious, or a slower and conscious, representation is used to initiate a visually guided response.
- Published
- 2011