ON CONDITIONED REINFORCING EFFECTS OF NEGATIVE DISCRIMINATIVE STIMULI

Abstract

Observing responses by pigeons were studied during sessions in which a food key and an observing key were available continuously. A variable‐interval schedule and extinction alternated randomly on the food key. In one condition, food‐key pecking during extinction decreased reinforcement frequency during the next variable‐interval component, and in the other condition such pecking did not affect reinforcement frequency. Observing responses either changed both keylight colors from white to green (S+) or to red (S‐) depending on the condition on the food key, or the observing responses never produced the S+ but produced the S‐ when extinction was in effect on the food key. Observing responses that produced only S‐ were maintained only when food‐key pecking during extinction decreased reinforcement frequency in the subsequent variable‐interval component. The red light conformed to conventional definitions of a negative discriminative stimulus, rendering results counter to previous findings that production of S‐ alone does not maintain observing. Rather than offering support for an informational account of conditioned reinforcement, the results are discussed in terms of a molar analysis to account for how stimuli acquire response‐maintaining properties.