Discriminative control of choice by reinforcers in children and adults

Research with nonhumans and human children has questioned the notion of the strengthening properties of reinforcers when choices are controlled by what reinforcers signal about upcoming events. We extended this work by developing and evaluating an automated task to evaluate the discriminative versus strengthening effects of reinforcers with two children of typical development (Experiment 1) and 18 university students (Experiments 2 and 3). Participants responded by touching one of two concurrently available images on a touchscreen. Across conditions, the probability that the next reinforcer would be delivered at the same location as the immediately preceding reinforced response varied with probabilities of .10 (switch), .50 (control), and .90 (stay). Both children and students responded according to the arranged reinforcer probabilities of the next reinforcer instead of where the most recent reinforcer had been delivered. The present findings add to the body of work suggesting that reinforcers serve a discriminative function, and we use a quantitative model of reinforcer misallocation to account for choices being imperfectly controlled by contingencies.