Subordinate categorization requires conscious awareness

Document Type: 
ASSC Conference Item
Disciplines: 
Neuroscience
Topics: 
Unconscious States Processing
Keywords: 
binocular rivalry, continuous flash suppression, gender, race, face processing
Deposited by: 
Ido Amihai
Contact email: 
idoamihai@yahoo.com
Date of Issue: 
2010
Authors: 
0
Event Dates: 
24-27 June 2010
Event Location: 
Toronto, Canada
Event Title: 
14th annual meeting of the Association for the Scientific Study of Consciousness
Event Type: 
ASSC Conference
Presentation Type: 
Talk
Refereed: 
No
Abstract: 
Neuroimaging studies demonstrate that categorical processing of faces can occur even in the absence of conscious awareness. However, the extent to which information about subordinate properties such as gender, age, race or identity can be extracted without awareness of the perceived stimulus is still debated. Our present experimental results suggest a need for conscious awareness in the processing of subordinate information. Using the FaceGen Modeller software, we generated faces that were ambiguous either with respect to gender or to race, and presented them immediately after prime faces that clearly belonged to a certain race or gender (an extremely male or extremely female face in the gender classification task and extremely Caucasian or extremely Asian face in the race classification task). As previously reported, when conscious vision was unhindered, the classification of the ambiguous faces was biased contrary to the category represented by the immediately preceding prime. In contrast, no bias was observed when the primes were rendered consciously invisible via continuous-flash-suppression. Moreover, we found a correlation between the bias strength and the exposure time of the prime only when it was consciously visible, indicating that the processing of subordinate information clearly depends on the amount of time that a stimulus is subjectively visible. Previous data show that affective images that are presented below the threshold of conscious awareness can both activate specific brain regions and influence the affective judgments of subsequent stimuli, possibly through a neural route that travels directly from the superior colliculus to the limbic system and bypasses the visual cortex. Our data shows that such routes are the exception, and are not available for subordinate categorization that is based on form aspects of the visual stimulus, such as a face’s gender and race. Thus, despite the enthusiasm about evidence for residual categorical processing without awareness, conscious awareness is required for information extracted from faces to affect behavior.
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ASSCpresentation7.ppt1.81 MB