Graduation Year

2006

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Psychology

Major Professor

Mark S. Goldman, Ph.D.

Keywords

Event-related potentials, P300, Expectancy violation, Individual differences, Semantic networks

Abstract

Considerable evidence indicates that the expectations individuals hold about the effects of alcohol determine, to a degree, the amount of alcohol they drink. However, the bulk of this evidence was acquired using verbally-based measures of expectancy. The present study sought to extend the validation network by utilizing an electrophysiological measure -- the P300 component of the Event Related Potentials (ERPs) --

which is thought to index fundamental neurophysiological processes sensitive to expectancy.Previous research has demonstrated that, when presented with various outcomes of alcohol consumption, heavier drinkers endorse statements that assert positive and arousing effects of alcohol, while lighter drinkers endorse sedating and negative effects of alcohol. Given the sensitivity of the P300 to violation of subjective expectancies, it was hypothesized that P300 amplitude elicited by stimuli violating one's alcohol expectancies (e.g., statements describing sedating effects of alcohol for individuals with high positive expectancies) would be correlated with the participants' alcohol expectancies measured by traditional self-report measures.Participants were presented with statements reflecting a wide range of alcohol outcome effects, which either violated or confirmed the participant's own set of alcohol expectancies, while the ERPs evoked by these stimuli were recorded. As predicted, the P

300 amplitude elicited by negative alcohol expectancy stimuli was positively correlated with the degree of endorsement of positive/arousing expectancies on the self-report measure. That is, the higher the individual's positive/arousing expectancies, the larger the P300 elicited by stimuli asserting the negative effects of alcohol. There was no significant correlation, however, between P300 amplitude elicited by positive alcohol expectancy stimuli and the degree of endorsement of negative/sedating expectancies on the self-report measure.In sum, variations in the amplitude of the P300 were consistent with the model of Alcohol Expectancies: Namely, words imputing negative/sedating effects of alcohol elicited a large P300 in individuals with high but not low positive alcohol expectancies. By indexing the brain's electrophysiological response sensitive to expectancy violations, these findings demonstrate concordance between verbal measures of alcohol expectancies, which by their very nat

ure are introspective, and a psychophysiological index of expectancy thought to operate automatically and to be independent of overt responding.

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