Chapter 3 - Aversive Learning Situations: Apparatus and Procedures

Abstract

This chapter discusses the apparatus and procedures of aversive learning situations. The ideal punishing or aversive stimulus has the following characteristics. It should have precise physical specification, the contact the stimulus makes with the subject should be constant, the subject should not be able to escape or minimize stimulation by means of some unauthorized or unwanted behavior, there should be few skeletal reactions to the stimulus, and the experimenter should have the option of varying the aversive stimulus over a wide range of values. The aversive stimulus that best meets these criteria is, perhaps, shock. Footshock has been the most extensively used aversive stimulus. Other aversive stimuli that have been used are air blasts with cats, bar slap with rats, noise with humans, extremes of water temperature, and even objects that elicit fear reactions in animals, for example, monkeys fear moving toy bears. A number of parameters of aversive stimuli have been manipulated. Among such variations are the intensity of the aversive stimulus, the duration of the aversive stimulus, the frequency or percentage of the aversive stimulus, the schedule such as fixed ratio according to which the aversive stimulus is delivered, the immediacy or delay of the aversive stimulus, and whether the aversive stimulus is introduced at full strength or increased gradually over a series of trials.