The psychological factors of a premature response based on contingent negative variation.

The psychological factors of a premature response on simple reaction-time tasks were examined by comparing the difference between control responses (33 samples) and premature responses (33 samples) using the index of Contingent Negative Variation (CNV). The first (warning) stimulus was a click, the second (imperative) stimulus was a colored circular figure presented on a CRT, and the interstimulus interval was set at 3 sec. 72 trials were administered to the 24 subjects, then 33 artifact-free CNV data in a premature response were shown. Analyses indicated that CNV amplitudes in the premature response were lower than those in the control response at frontal position. Especially in the premature response, CNV waveforms stayed around baseline toward S2 at F3 and F4. In the analyses of variance, every CNV component (early, late, and whole components) at F4 or FZ was significantly lower for the premature response. These results suggested that the optimal prediction, arousal, and attention do not seem to be maintained in a premature response.