The present experiment investigates the influence of an unexpected change from an escape paradigm to uncontrollability on slow cortical potentials (SCPs) and autonomic responses (heart rate, skin conductance, and EMG). Two groups of 10 male students each participated in a reaction time experiment; subjects heard one of two warning stimuli (WS) of 6 sec duration, which signaled one of two imperative stimuli (IS), an aversive noise or a neutral tone. Subjects in the experimental group could escape the IS by pressing a microswitch within 300 msec after the onset of the IS. This possibility to escape was interrupted after an experimental period of 40 trials for another period of 40 trials, during which the IS lasted for 5 sec irrespective of the actual motor response of the subject. Yoked control subjects received WS and IS in the same sequence and length as the matched experimental partner but without having any experience of control of the IS. During the WS-interval all subjects showed a two-component negative shift of SCPs. In response to the uncontrollable aversive IS during the second experimental period, experimental subjects showed a marked postimperative negative variation (PINV). No comparable PINV was found in response to the neutral IS or in the yoked control subjects. The PINV was, furthermore, more pronounced in subjects who showed a larger differentiation in the late component of the negative shift between the aversive and the neutral WS during the first 40 trials.
|Number of pages||7|
|Publication status||Published - 1979|
ASJC Scopus subject areas
- Physiology (medical)
- Experimental and Cognitive Psychology
- Neuropsychology and Physiological Psychology