Electrodermal lability and simple reaction time.

Subjects identified as electrodermally labile or stabile (n = 10 per group) on the basis of non-specific electrodermal fluctuations and a trials-to-criterion measure of habituation were compared in a simple reaction time (RT) task that employed long, variable foreperiods (from 8 to 19 s). Labiles had significantly faster RTs across all foreperiods, but there were no differences in RT variability between the groups. Phasic heart rate responses recorded concurrently through the foreperiod showed a characteristic pattern of acceleratory and deceleratory activity, which was similar among both labiles and stabiles. The findings indicate that labiles and stabiles show a consistent difference in the speed of processing of a target imperative stimulus, which is not due to differences in response preparation processes. Overall, the results support the use of RT paradigms for evaluating individual differences in information-processing associated with electrodermal lability.