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Visual processing in rapid-chase systems: image processing, attention, and awareness.

Schmidt T, Haberkamp A, Veltkamp GM, Weber A, Seydell-Greenwald A, Schmidt F - Front Psychol (2011)

Bottom Line: We propose that response priming captures the output of the first feedforward pass of visual signals through the visuomotor system, and that this output lacks some characteristic features of more elaborate, recurrent processing.This way, visuomotor measures may become dissociated from several aspects of conscious vision.We argue that "fast" visuomotor measures predominantly driven by feedforward processing should supplement "slow" psychophysical measures predominantly based on visual awareness.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Social Sciences, Psychology I, University of Kaiserslautern Kaiserslautern, Germany.

ABSTRACT
Visual stimuli can be classified so rapidly that their analysis may be based on a single sweep of feedforward processing through the visuomotor system. Behavioral criteria for feedforward processing can be evaluated in response priming tasks where speeded pointing or keypress responses are performed toward target stimuli which are preceded by prime stimuli. We apply this method to several classes of complex stimuli. (1) When participants classify natural images into animals or non-animals, the time course of their pointing responses indicates that prime and target signals remain strictly sequential throughout all processing stages, meeting stringent behavioral criteria for feedforward processing (rapid-chase criteria). (2) Such priming effects are boosted by selective visual attention for positions, shapes, and colors, in a way consistent with bottom-up enhancement of visuomotor processing, even when primes cannot be consciously identified. (3) Speeded processing of phobic images is observed in participants specifically fearful of spiders or snakes, suggesting enhancement of feedforward processing by long-term perceptual learning. (4) When the perceived brightness of primes in complex displays is altered by means of illumination or transparency illusions, priming effects in speeded keypress responses can systematically contradict subjective brightness judgments, such that one prime appears brighter than the other but activates motor responses as if it was darker. We propose that response priming captures the output of the first feedforward pass of visual signals through the visuomotor system, and that this output lacks some characteristic features of more elaborate, recurrent processing. This way, visuomotor measures may become dissociated from several aspects of conscious vision. We argue that "fast" visuomotor measures predominantly driven by feedforward processing should supplement "slow" psychophysical measures predominantly based on visual awareness.

No MeSH data available.


Related in: MedlinePlus

Results from Schmidt et al. (2010). Upper panel: results of the matching task where participants matched the brightness of the targets to the brightness of the adjacent flankers. Stippled lines denote veridical values. Lower panels: priming effects. Note the reversal in priming for response times and error rates under the attenuation condition.
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Figure 6: Results from Schmidt et al. (2010). Upper panel: results of the matching task where participants matched the brightness of the targets to the brightness of the adjacent flankers. Stippled lines denote veridical values. Lower panels: priming effects. Note the reversal in priming for response times and error rates under the attenuation condition.

Mentions: As expected, the matching task confirmed the effect of the illusion (Figure 6, upper panel). In the enhancing condition, the bright flanker was judged too bright, and the dark flanker was judged too dark, while in the attenuating condition, the bright flanker was judged too dark, and the dark flanker was judged too bright. (Matching was nearly veridical in the neutral condition). Importantly, the more luminant flanker was always judged brighter than the less luminant flanker, and the illusion never led to a reversal of the perceived brightnesses.


Visual processing in rapid-chase systems: image processing, attention, and awareness.

Schmidt T, Haberkamp A, Veltkamp GM, Weber A, Seydell-Greenwald A, Schmidt F - Front Psychol (2011)

Results from Schmidt et al. (2010). Upper panel: results of the matching task where participants matched the brightness of the targets to the brightness of the adjacent flankers. Stippled lines denote veridical values. Lower panels: priming effects. Note the reversal in priming for response times and error rates under the attenuation condition.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3139957&req=5

Figure 6: Results from Schmidt et al. (2010). Upper panel: results of the matching task where participants matched the brightness of the targets to the brightness of the adjacent flankers. Stippled lines denote veridical values. Lower panels: priming effects. Note the reversal in priming for response times and error rates under the attenuation condition.
Mentions: As expected, the matching task confirmed the effect of the illusion (Figure 6, upper panel). In the enhancing condition, the bright flanker was judged too bright, and the dark flanker was judged too dark, while in the attenuating condition, the bright flanker was judged too dark, and the dark flanker was judged too bright. (Matching was nearly veridical in the neutral condition). Importantly, the more luminant flanker was always judged brighter than the less luminant flanker, and the illusion never led to a reversal of the perceived brightnesses.

Bottom Line: We propose that response priming captures the output of the first feedforward pass of visual signals through the visuomotor system, and that this output lacks some characteristic features of more elaborate, recurrent processing.This way, visuomotor measures may become dissociated from several aspects of conscious vision.We argue that "fast" visuomotor measures predominantly driven by feedforward processing should supplement "slow" psychophysical measures predominantly based on visual awareness.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Social Sciences, Psychology I, University of Kaiserslautern Kaiserslautern, Germany.

ABSTRACT
Visual stimuli can be classified so rapidly that their analysis may be based on a single sweep of feedforward processing through the visuomotor system. Behavioral criteria for feedforward processing can be evaluated in response priming tasks where speeded pointing or keypress responses are performed toward target stimuli which are preceded by prime stimuli. We apply this method to several classes of complex stimuli. (1) When participants classify natural images into animals or non-animals, the time course of their pointing responses indicates that prime and target signals remain strictly sequential throughout all processing stages, meeting stringent behavioral criteria for feedforward processing (rapid-chase criteria). (2) Such priming effects are boosted by selective visual attention for positions, shapes, and colors, in a way consistent with bottom-up enhancement of visuomotor processing, even when primes cannot be consciously identified. (3) Speeded processing of phobic images is observed in participants specifically fearful of spiders or snakes, suggesting enhancement of feedforward processing by long-term perceptual learning. (4) When the perceived brightness of primes in complex displays is altered by means of illumination or transparency illusions, priming effects in speeded keypress responses can systematically contradict subjective brightness judgments, such that one prime appears brighter than the other but activates motor responses as if it was darker. We propose that response priming captures the output of the first feedforward pass of visual signals through the visuomotor system, and that this output lacks some characteristic features of more elaborate, recurrent processing. This way, visuomotor measures may become dissociated from several aspects of conscious vision. We argue that "fast" visuomotor measures predominantly driven by feedforward processing should supplement "slow" psychophysical measures predominantly based on visual awareness.

No MeSH data available.


Related in: MedlinePlus