Is the Contingent Negative Variation Contingent on a Motor Response?

Emanuel Donchin, University of South Florida
L. K. Gerbrandt, NASA-Ames Research Center
Larry John Leifer, Stanford Univesity
Ledyard Tucker

Abstract

Ten subjects participated in an experiment in which each was presented with series of paired stimuli separated by 1000 msec. The first stimulus was a click. The second stimulus was either of two visual patterns, concentric circles or a star figure. Figure selection on each trial was determined by a random procedure.

There were four experimental conditions: 1) Subjects pressed a switch following the presentation of either figure. 2) Subjects pressed a switch following the presentation of the star only. 3) Subjects guessed prior to the clicks, which figure would appear as S2; no overt motor response was required. 4) Subjects had to add 7 to a cumulative sum following a star, and subtract 7 following the circles; no overt motor response was required.

Using data obtained from a vertex to linked ear derivation we conclude that the CNV is not contingent on a motor response to S2.

The electrical potentials recorded following S2, and in particular the positive-going “resolution” of the CNV seemed to vary systematically with the experimental conditions. An application of Tucker's three-mode factor analysis to this CNV is reported.