Two groups of 26 male college students, one scoring in the upper 10% and one scoring in the lower 10% of the Bendig test of emotionality (original sample, N = 200), were studied under a "low-stress" and a "high-stress" condition. Contingent negative variations (CNV) and galvanic skin responses (GSR) were recorded in a differential reaction time paradigm. Under low stress (flash-flash, response) both groups demonstrated equal CNV amplitudes. Under high stress (flash-intense electrical shock, response) the high emotionality group had smaller CNVs when response was made to intense shock than did the low emotionality group. Neither anticipatory GSRs nor reaction times differentiated the groups. The data are interpreted as suggesting a higher basal cortical negativity in the high emotionality group which prevented CNVs from reaching values beyond a physiologically determined maximum value.
Knott JR, Irwin DA. Anxiety, Stress, and the Contingent Negative Variation. Arch Gen Psychiatry. 1973;29(4):538-541. doi:10.1001/archpsyc.1973.04200040080013