Key points are not available for this paper at this time.
ABSTRACT Signals were used to manipulate S's ability to predict when and where (i.e., on which limb) he would receive each of 48 painful shocks. Two groups of 24 Ss received 12 shocks in each of four predictability conditions. Heart rate and palmar SC were monitored throughout. Both HR and SC responses to shock were consistently reduced when shock was preceded by a warning signal; predictability of locus had no effect on HRR and a weak effect on SCR. More anxious Ss showed greater post‐shock HR acceleration under all conditions; less anxious Ss showed greater anticipatory HR acceleration. In a separate experiment, 9 Ss in whom the later components of the vertex AER increased systematically with shock intensity showed a decrease in these same components when shock was made predictable in time.
Lykken et al. (Mon,) studied this question.