Brain Indices of Nonconscious Associative Learning

Authors: Wong P.S.¹; Bernat E.²; Bunce S.²; Shevrin H.²

Source: Consciousness and Cognition, Volume 6, Number 4, December 1997 , pp. 519-544(26)

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Abstract:

Using a classical conditioning technique, this study investigated whether nonconscious associative learning could be indexed by event-related brain activity (ERP). There were three phases. In a preconditioning baseline phase, pleasant and unpleasant facial schematics were presented in awareness (suprathreshold). A conditioning phase followed, in which stimuli were presented outside awareness (subthreshold, via energy masking), with an unpleasant face (CS+) linked to an aversive shock and a pleasant face (CS-) not linked to a shock. The third, postconditioning phase, involved stimulus presentations in awareness (suprathreshold). Evidence for acquisition of a conditional response was sought by comparing suprathreshold pre- and postconditioning phases, as well as in the subthreshold conditioning phase itself. For the pre-postconditioning phase analyses, significant ERP component differences differentiating CS+ and CS- were observed for N1, P2, and especially P3. For the conditioning phase, significant differences were observed in the 100–400 ms. post-stimulus region reflecting a CS+ processing negativity. Brain activity does indeed index the acquisition of a conditional response to subthreshold stimuli. Associative learning can occur outside awareness. Copyright 1997 Academic Press.

Language: English

Document Type: Research article

Affiliations: 1: Department of Psychology, New School for Social Research, New York, New York, 10003 2: Department of Psychiatry, University of Michigan Medical Center, Ann Arbor, Michigan

Publication date: 1997-12-01