Report of Panel II: The ERP and Decision and Memory Processes
|Panel chair:||T. Picton|
|Panel members:|| E. Donchin|
Picton: I shall begin with an apology. Our presentation may not correspond to your expectations because our panel failed to identify a clear interface between cognitive psychology and the event-related potentials. We shall not propose crucial experiments to determine the psychophysiological mechanisms of human memory and decision. Rather, we shall concentrate on the "P300" wave and its possible psychological meaning. I shall begin by presenting a "classical data base." These data place constraints on any theory of P300 that might be suggested. I shall identify four major aspects of the available data.
The first important attribute of the late positive component is its timing. This is usually measured as the latency to the peak of the component. It is crucial to note that the P300 may occur before, during, or after the point in time when a decision is possible. This relation of the P300 latency to the timing of mental events is discussed in greater detail in Chapter 10.
A second important fact is that P300 is very much related to attention. P300 is not elicited by an unattended stimulus. There are two significant corollaries of the statement that events must be attended if they are to elicit a P300. First, attention is intimately related to "conscious awareness." I feel strongly that the P300 is elicited only if the subject is aware of the signal that elicited it. Of course, the subject may be conscious of stimuli that do not elicit a measurable P300. Nevertheless, if a P300 did appear, the subject must have been aware of the eliciting event. Second, attention has an intensity--subjects may