Joseph Halpern

Small-Trials Partial Reinforcement Effects in Humans: The Role of Sequential Variables

The acquisition sequences in Experiment I combined light-off (-) trials with either 46% or 71% light-on (+) trials; those in Experiment II had either 2 or 4 -+ transitions, or run lengths of the event of 1, 2, or 3. Extinction, administered after very limited acquisition training, consisted of only trials. It was found that resistance to extinction increased as a direct function of the number of + transitions and the length of the run of trials.

Two choice discrimination learning as a function of stimulus similarity along an auditory intensity dimension

One hundred-twenty Ss received 300 trials in a simple auditory discrimination learning situation. Each of two pure tones was associated with one of the alternative choice responses, and the combinations S1-A-1 and S2-A2 were reinforced 100% with events E1 and E2, respectively. The two tones differed only in their intensity, and ?I was varied between 0 and 6 db. Proportion correct responses was a linear increasing function of ?I, and there was no stimulus intensity dynamism effect on response probability.