Feature-positive and feature-negative discrimination learning maintained by negative reinforcement in rhesus monkeys

Abstract

Rhesus monkeys were trained to press panels to escape or avoid shock. Escape and avoidance training were combined factorially with feature-positive (FP) and feature-negative (FN) discriminations. In the FP situation, S+ trials were characterized by one red and two green panel displays and S-consisted of an all green panel array. In the FN arrangement, S+ and S-arrays were reversed. When compared properly, FP discriminations were learned more readily than FN discriminations in both escape and avoidance training conditions. Positive tracking was associated with FP discriminations, and feature avoidance characterized the FN tasks. These data suggest that in primates, feature responses (i.e., tracking behaviors) are more a function of the operant contingency than of the Pavlovian correlation.An interesting phenomenon in the area of discrimination learning, and one which has attracted increasing amounts of experimental attention, is the featurepositive effect, FPE, first described by Jenkins and Sainsbury (1969). Consider a go/no-go problem in which an animal is required to differentiate between a white stimulus and a white stimulus with a dot superimposed on it. Whether the subject learns the discrimination is apparently a function of which of these stimuli is designated as S+ and which is S-. If the animal is reinforced for responding to the stimulus containing the dot, or feature, but reinforcement is not available for responding to the blank white key, the condition is labeled feature positive (FP), and discrimination learning appears rapidly. However, in the reverse arrangement, in which the stimulus containing the feature appears exclusively as S-and the blank white stimulus appears as S+, learning is considerably more difficult. As a matter of fact, this feature-negative (FN) task is frequently characterized by a complete absence of learning. It is this asymmetry in learning FP discriminations relative to FN discriminations which constitutes the FPE.

The ontogeny of the feature-positive effect in young chicks

“…The FPE has also been established with a variety of responses and reinforcers, and across a wide variety of subject populations, including rats (Reberg & LeClerc, 1977), pigeons (Jenkins & Sainsbury, 1969, 1970, monkeys (McCoy & Yanko, 1983;Pace, McCoy, & Nallan, 1980), human children (Sainsbury, 1971), and adults (Newman, Wolff, & Hearst, 1980). The wide generality of the phenomenon, as well as the demonstration of the FPE in humans, has caused speculation that the FPE may not reflect learned response tendencies.…”