Updating p300 an integrative theory of p3a and p3b subscribe newsletter dating
Chapman and Bragdon speculated that this differential response to the numbers, which came to be known as the P300 response, resulted from the fact that the numbers were meaningful to the participants, based on the task that they were asked to perform.In 1965, Sutton and colleagues published results from two experiments that further explored this late positivity.They observed a positivity around 300 ms after the second click occurred or would have occurred in the case of the single click.They also had subjects guess how long the interval between clicks might be, and the late positivity occurred 300 ms after the second click.
More specifically, this ERP component has played a key role in cognitive psychology research on information processing.Generally speaking, improbable events will elicit a P3b, and the less probable the event, the larger the P3b.However, in order to elicit a P3b, the improbable event must be related to the task at hand in some way (for example, the improbable event could be an infrequent target letter in a stream of letters, to which a subject might respond with a button press).For every two numbers, the subjects were required to make simple decisions, such as telling which of the two numbers was numerically smaller or larger, which came first or second in the sequence, or whether they were equal.
When examining evoked potentials to these stimuli (i.e., ERPs), Chapman and Bragdon found that both the numbers and the flashes elicited the expected sensory responses (e.g., visual N1 components), and that the amplitude of these responses varied in an expected fashion with the intensity of the stimuli.
They presented subjects with either a cue that indicated whether the following stimulus would be a click or a flash, or a cue which required subjects to guess whether the following stimulus would be a click or a flash.