Effects of Amobarbital Sodium and Meprobamate on Acquisition of Conditioned Avoidance

Abstract

The purpose of these experiments was to study the effects of two “fear-reducing” drugs, amobarbital sodium and meprobamate, on the acquisition of a conditioned avoidance response in albino rats, and how this response is related to general activity level and freezing behavior. Both drugs facilitated acquisition of the avoidance response and increased activity level as measured by the number of spontaneous inter-trial hurdle crossings. Thus, these results seemed at variance with Mowrer's theory regarding the relationship of fear to the avoidance response. However, the results were compatible with the theory that the relationship of performance to motivation is an inverted U-shaped function, which suggests that amobarbital and meprobamate exerted their facilitating effects on avoidance performance by obtunding the strong fear-freezing response which is known to be incompatible with the emission of the avoidance response.