Adaptation in energy mobilization: changes in general level of palmar skin conductance.

Abstract

Palmar skin conductance has with justification been regarded as an index of degree of energy mobilization. Measurement of the general level of palmar conductance was, therefore, employed as a means of investigating adaptation effects in energy mobilization during successive rest periods and successive repetitions of a task. The task employed was that of making auditory discriminations. A series of tones, varying in intensity from zero decibels to an intensity just below the subject''s limen, was presented at regular intervals to 10 subjects, 4 times during an exptl. session, on 3 consecutive days at the same hr. The subject responded by a tap of the foot whenever a tone was heard. Palmar resistance was recorded at 15-sec. intervals, during the stimulus series and during the rest period preceding the exptl. session. Resistance measures were translated into the reciprocal value-conductance. Decreasing conductance, indicating a decrease in energy mobilization, was found: 1) In the course of the rest period preceding the presentation of stimuli; 2) from series to series during the 4 repetitions of the series of auditory discriminations which occurred in a single exptl. session; 3) from day to day throughout the 3-day period of the experiment, during both (1) the rest period, and (2) auditory discriminations. The differences found are statistically significant. Adaptation effects in energy mobilization are thus shown to occur upon the repetition of a stimulus situation within a given exptl. session and from day to day. The phenomenon is similar to the well recognized decrease in useless overt movements sometimes plotted as a "learning curve". The internal processes of energy mobilization, like the overt responses of the individual, show increasing adaptation to the situation[long dash]or "learning".