Avoidance learning as a function of several training conditions and strain differences in rats.

Abstract

The simplest interpretation of current avoidance learning theories (Solomon & Brush, 1956) might lead one to believe that successful avoidance responding almost inevitably develops if a discriminable cue consistently precedes painful stimulation that motivates vigorous escape responding, and if anticipatory performance of that response can avoid the painful stimulation. As the following study will show, such is hardly the case. Several variables which demand a more adequate theoretical formulation appear to have a great effect on the success or failure of simple avoidance training. No doubt many experimenters have, after trial and error, concentrated on particular conditions which reliably produce learning, avoiding the exceptions both empirically and theoretically. As Solomon and Brush (1956) maintain, "Failures of .Ss to learn to avoid are not rare, but they are less apt to be reported in scientific papers than are the successes" (p. 215).The present experiment grew out of pilot studies in which rats unexpectedly failed to learn shock-avoidance responses in seemingly conventional Skinner-box training situations. Five variables which seemed most relevant to success and failure were investigated. These were: (a) The type of conditioned stimulus. A buzzer and a 4,000-cycle sine-wave tone were chosen as two stimuli that gave markedly different results in pilot studies, (b) The type of response. Two different responses were chosen: pressing a bar and rotating a drumtype wheel, (c) The method of applying shock. In one condition, the wheel or bar was electrified along with the grid floor and walls when S was shocked for failure to make an avoidance

Active avoidance learning in hamsters

“…The higher number of avoidances obtained with the acoustic CS may be related to an effectiveness intrinsic to this kind of stimulus in producing avoidance. This has been shown in rats by Myers (1959) who suggests that the startle 150 response elicited by the buzzer serves to antagonize the freezing pattern produced by fear.…”

RESPONSE COST AND THE AVERSIVE CONTROL OF HUMAN OPERANT BEHAVIOR1

“…This finding taken together with the high frequency of PLPs under cost on the avoidance-escape schedule suggests the possibility that response cost may be an important factor in the substantial number of Ss who fail to acquire an instrumental avoidance response (Ader and Tatum, 1961) and in the extensive training often required for even ultimately "successful" avoiders (Meyer, Cho, and Wesemann, 1960). It may be, for example, that the frequently observed freezing-crouching patterns of animals, when electric shock is used to shape avoidance responding (Meyers, 1959), adds "physical costs" to responding which interfere with the development of avoidance behavior.…”

On the differences between animals that learn and do not learn to avoid electric shock

“…Some experimenters, e.g., Schaeffer (1959), reduce the severity of the problem by selecting strains of rats containing a high proportion of animals that learn, others, e.g., D'Amato, Keller, & DiCara (1964) and Baum (1965), manipulate the apparatus and training procedure to favor rapid learning, and still others, e.g., Myers (1959), combine the two approaches.…”