AN INEXPENSIVE APPARATUS FOR PRESENTING AVERSIVE STIMULATION TO RODENTS IN A SOCIAL SITUATION

Abstract

Sz~mmary.-An apparatus and procedure are described for presenting subcutaneous shock sirnultancously to cwo tats for the purpose of eliciting social behavior. Preliminary observations suggest that a full range of agonistic postures are elicited by this arrang-ment and that they are quite similar to behaviors elicited by grid shock. A major problem with using electric shock in free-operant situations is its application through a grid :o the animal's feet. Since S is free-moving, changes in foot placement or posture often alter the effects of the shock. The use of constant current stimulators and various kinds of grid scramblers for alternating the respective grids which ate hot, have been only partial solutions to chis problem, as other investigators have noted (Azrin & Holz, 1966; Dinsmoor, 1961). These problems are particularly acute in experiments in which elicited behaviors ate studied (e.g., shock-elicited aggression, SEA). During the course of an experiment S may instrumencally acquire a partial escape response of some kind which later interferes with the natural occurrence of the respondent behav~or being studied. Where a single animal is studied, subdermal electrodes sutured to the hide and exiting via microminiature connectors through a slip-ring assembly or mercury commutator have sufficed (e.g., see Campbell 8: Moorcroft, 1970). Where the animal is partially restrained such electrodes may be merely attached to the surface of the skin (Weiss, 1967; Azrin, Rubin, & Hutchinson, 1968; Rubin & Aztin, 1967). However, with the exception of the latter study involving the sexual behavior of rabbits, none of chese solutions have been used to study social behaviors, as in experiments on shock-elicited aggression, for example. We report here the use of a technique which is suitable for studying two animals simultaneously in which subdermal electric shock is separately presented to each animal. Such a procedure may likewise be used for making various kinds of psychophysiological recordings or for studying the effects of CNS stimulation upon social behaviors. However, it originated from attempts to gain greater control over the eliciting stimulus in studies of shock elicited aggression.