Heart rate and disjunctive reaction time: the effects of discrimination requirements.

Abstract

In three experiments, 5s were given series of easy or difficult auditory discriminations in the context of a fixed foreperiod disjunctive reaction time task. Tonic heart rate was slower during series of difficult trials than during series of easy trials, when they were presented in separate sessions. When they were given in two halves of the same session, this result was not replicated. When easy and difficult trials were presented'in a random order, and information was provided at the beginning of the foreperiod about the difficulty of that trial, phasic deceleration was greater on difficult trials. Peak-to-trough change was negatively related to reaction time in all experiments. The results are discussed in terms of Lacey's intake-rejection hypothesis.