Activation and Behavior. I: Relationship between Physiological “Indicants” of Activation and Performance during Memorization of Nonsense Syllables Using Differing Induced Tension Conditions

Abstract

This is the first of a series of studies oriented toward determining what physiological variables constitute the most reliable and valid indices of activation level; what is the minimal number of variables required to estimate accurately general activation level as well as patterns of activation, taking into account the activity of both the autonomic and somatic nervous systems; and how each variable relates to performance under specified conditions. The primary purpose of this study was to ascertain how four different “indicants” of activation level relate to one another and to verbal performance under different induced tension conditions. Sixteen Ss memorized 16 5-syllable lists of 3-letter nonsense syllables under 16 conditions in a single experimental session, using a balanced Latin square to control for order effects. The conditions were generated by various combinations of three independent variables: (1) mode of syllable presentation (visual vs auditory); (2) method of inducing tension (lifting weights vs squeezing hand dynamometer); and (3) amount of induced tension (5, 10, 15, and 20 lbs.). Each trial was 2 min. long, being followed by 2 min. of rest. Orderly within- and between-trial changes were noted in skin conductance, heart rate, and neck and forearm flexor tension level, but the changes varied, respectively, among the four variables from decreasing to increasing functions. This gradual transition was explained in terms of the relative degree of control the autonomic and somatic nervous systems exerted on each of the variables. The decreasing functions probably reflect a gradual reduction in the degree of anxiety or apprehensiveness experienced by Ss; the increasing functions probably reflect an increase in the amount of muscular effort exerted by Ss in order to maintain a specified amount of force on a hand grip device. Increasing amounts of induced tension caused performance to deteriorate and caused heart rate and forearm flexor tension level to increase. The manner in which the syllables were presented and method of inducing tension significantly affected performance but not the physiological variables.