A Psychophysio-Logical Analysis of Bargaining: ERPs and Facial Expressions

Document Type


Publication Date


Digital Object Identifier (DOI)



The amplitude of the P300 component of the event-related brain potential (ERP) is affected by subjective probability; the lower the subjective probability assigned to an event, the larger the P300 elicited by that event (Donchin, 1979; Donchin and Isreal, 1980; Squires et al.. 1977; Squires et al.. 1976). This pattern of results suggests that the amplitude of P300 may be used to determine if, and when, the subject detects the occurrence of an unexpected event in a fairly complex series of events. In studies of bargaining there is a need to determine when, and if, a subject detects a shift in the strategies of the opponent. In this study subjects played a complex bargaining game with our computer to determine whether “surprising” changes in the computer’s strategy would elicit a P300; our intent was to explore the extent to which changes in P300 amplitude could be used in the study of the bargaining process. In a second experiment subjects were videotaped to determine if changes in facial expressions were evoked by the same surprising events, and to assess the correlation between facial feature changes and the P300.

Was this content written or created while at USF?


Citation / Publisher Attribution

Brain and Information: Event-Related Potentials, v. 425, issue 1, p. 230-235