Discrimination performance as affected by duration of shock for either the correct or incorrect response

Abstract

The present study extends our assessment of various shock parameters and training procedures as possible determinants of the paradoxical facilitating effect of shock for the correct response in discrimination training. Eighty hungry rats were trained with a non-correction procedure to make a light-dark discrimination for food under various durations of shock for either the right or wrong response. Trend analyses showed that, with greater durations of shock, errors decreased for the shock-wrong Ss but remained constant for the shockright Ss and did not depart significantly from the performance of no-shock controls. The data delimit any broad generalization that shock for the correct response facilitates discrimination performance. ProblemThe paradoxical finding reported by Muenzinger and his colleagues (e. g., Muenzinger, 1934;Muenzinger et al., 1938) that shock for the correct response facilitates discrimination performance appears generally accepted despite the results of more recent investigations which have failed to demonstrate the effect and point up the import of considering various classes of determining variables, including training procedures and shock parameters. In one of these studies (Wischner et al., 1963), investigation of the effect of shock intensity showed that, with a non-correction procedure, increasing intensities of shock reduced errors for shock-wrong (SW) groups but increased them for shock-right (SR) groups, all of the latter being inferior to no-shock (NS) controls. These results were interpreted as favoring an avoidance interpretation of the function of shock and as being opposed to any broad generalization that shock for the correct response facilitates performance.The present study extends the previous one by assessing the effect of shock d u rat ion (with intensity held constant) on discrimination performance in a situation involving shock for either the correct or incorrect response, and a non-correction training procedure. MethodSubjects were 80 naive male albino rats, about 100 days old at the start of training. The Ss were caged individually in the experimental room under controlled temperature and an artificially illuminated day-night cycle.The apparatus was an enclosed T maze, the dimensions of which are reported elsewhere (Wischner etal.,1963 George J. Wischner and Barry FowlerUNIVERSITY OF PITISBURGH strips of sheet metal, each L serving as one wall and half of the floor. Together, the strips provided two 1 1/ 2 in floor surfaces separated by a 3/4 in gap. The discriminative stimuli were a dark alley and the illumination provided by a 10 wbulb positioned behind the frosted Plexiglas end wall of a goal compartment. A matched impedance shock system conSisting of a 60-cps AC source and a series resistance of .3 megohms was used to deliver shock to S when S interrupted in the appropriate arm an infra-red photoelectric beam crOSSing the arm at a point midway between the choice and goal sections. A manual priming feature of the circuit insured that S received only one sho...

Effect of punishment duration and intensity on the extinction of an instrumental response.

“…This generalization is applicable to the punishment (a) of erroneous responses during visual discrimination learning in pigeons and rats (Ferster & Appel, 1961, Exp. II;Wischner & Fowler, 1964), and (b) of a learned operant response in rats when positive reinforcement is continued during punishment sessions (Boroczi, Storms, & Broen, 1964;Storms, Boroczi, & Broen, 1963).…”

Facilitating stimulus effects of reward and punishment in discrimination learning

“…Consistent with this interpretation, the "shock-right" facilitation effect is typically absent in an easy discrimination in which the discriminative stimuli (e.g., light-dark) are highly dissimilar and hence preclude a distinctive-cue function of the shock (e.g., Wischner & Fowler, 1964;Wischner, Fowler, & Kushnick, 1963); in contrast, the facilitation effect is consistently observed in more difficult (e.g., bright-dim) discriminations in which the discriminative stimuli are similar and thus potentiate the shock's cue function (e.g., Fowler, Spelt, & Wischner, 1967;Fowler & Wischner, 1965). Furthermore, if the aversiveness of the shock is reduced through the administration of sodium amytal (Fowler, Goldman, & Wischner, 1968), the facilitation occurring in a difficult discrimination is, within limits, an increasing S-shaped function of shock intensity, consistent with the Weber principle relating performance to the discriminable cue properties (e.g., the intensity) of a stimulus.…”