The effects of differential outcomes and magnitude of reinforcement on pigeons acquisition rates in delayed matching to sample

The differential outcome effect refers to the increase in accuracy obtained in discrimination tasks when rewards provided for correct responses vary according to the stimulus presented. The current research compared a higher magnitude of reinforcement with a differential outcome to determine which condition would produce a higher rate or learning in a delayed matching to sample task. The participants were four White Carneaux pigeons. There were three conditions, one with the same outcomes of immediate access to 4s reinforcement serving as the control and two with differential outcomes involving a 2s delay to reinforcement for one outcome and immediate reinforcement for the other outcome. One differential outcome condition had 2 seconds of reinforcement and the other differential outcome condition had 4 seconds of reinforcement. An alternating treatment design was used for this study. Two of the four pigeons met mastery criteria for all three conditions. Results were mixed but the differential outcome condition with 2s reinforcement was mastered in fewer trials by two of the birds. Most birds mastered the colors fastest with immediate outcomes versus delayed outcomes.