Volume 5, Number 8, Abstract 8, Page 8a doi:10.1167/5.8.8 http://journalofvision.org/5/8/8/ ISSN 1534-7362
Metacontrast and binocular rivalry suppression reveal hierarchies of unconscious visual processing
Bruno G. Breitmeyer
Department of Psychology, University of Houston, Houston TX 77204-5022, and Center for Neuro-Engineering and Cognitive Sciences, University of Houston, Houston TX 77204-4005
[e-mail]
Haluk Ogmen
Department of Electrical & Computer Engineering, University of Houston, Houston TX 77204-4005, and Center for Neuro-Engineering and Cognitive Sciences, University of Houston, Houston TX 77204-4005
Alpay Koc
Department of Electrical & Computer Engineering, University of Houston, Houston TX 77204-4005
Abstract

Using metacontrast, we looked at target suppression and target recovery under binocular and dichoptic viewing of stimuli, with the ability to additionally introduce binocularly rivalry suppression in the latter viewing condition. Our investigations revealed the following functional hierarchy of unconsciously processing of visual stimuli: 1) Studies of masked priming showed that a target form can be processed unconsciously at levels that already have extracted, at minimum, conjunctions of primitive orientation features such as corners and vertices. 2) Studies of target recovery, produced by using a secondary mask to weaken the masking effect of the primary mask, showed that recovery is absent or greatly reduced under dichoptic presentation of the two masks, indicating that target recovery occurs primarily at unconscious levels prior to cortical binocular activation. 3) Studies of target recovery, produced by binocular rivalry suppression of the mask, showed that the cortical mechanism responsible for metacontrast suppression, itself activated at unconscious levels of cortical processing, occurs after the cortical level of binocularly rivalry suppression. Besides allowing us to establish functional hierarchies of unconscious processing in the cortical visual system, these results also allow us to distinguish between current models of target masking and recovery.
Supported by NSF grant BCS-0114533 and NIH grant R01-MH49892.

History
Received September 15, 2005; published September 23, 2005
Citation
Breitmeyer, B. G., Ogmen, H., & Koc, A. (2005). Metacontrast and binocular rivalry suppression reveal hierarchies of unconscious visual processing [Abstract]. Journal of Vision, 5(8):8, 8a, http://journalofvision.org/5/8/8/, doi:10.1167/5.8.8.
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