No abstract

Humans can monitor actions and compensate for errors. Analysis of the human event-related brain potentials (ERPs) accompanying errors provides evidence for a neural process whose activity is specifically associated with monitoring and compensating for erroneous behavior. This error-related activity is enhanced when subjects strive for accurate performance but is diminished when response speed is emphasized at the expense of accuracy. The activity is also related to attempts to compensate for the erroneous behavior.

To understand the endogenous components of the event-related brain potential (ERP), we must use data about the components' antecedent conditions to form hypotheses about the information-processing function of the underlying brain activity. These hypotheses, in turn, generate testable predictions about the consequences of the component. We review the application of this approach to the analysis of the P300 component. The amplitude of the P300 is controlled multiplicatively by the subjective probability and the task relevance of the eliciting events, whereas its latency depends on the duration of stimulus evaluation. These and other factors suggest that the P300 is a manifestation of activity occurring whenever one's model of the environment must be revised. Tests of three predictions based on this “context updating” model are reviewed. Verleger's critique is based on a misconstrual of the model as well as a partial and misleading reading of the relevant literature.

No abstract

Recent studies indicate that subjects may respond to visual information during either an early parallel phase or a later focused phase and that the selection of the relevant phase is data driven. Using the noise-compatibility paradigm, we tested the hypothesis that this selection may also be strategic and context driven. At least part of the interference effect observed in this paradigm is due to response activation during the parallel-processing phase. We manipulated subjects' expectancies for compatible and incompatible noise in 4 experiments and effectively modulated the interference effect. The results suggest that expectancies about the relative utility of the information extracted during the parallel and focused phases determine which phase is used to activate responses.