Reinforcement for errors in a signal-detection procedure

Six pigeons were trained on a signal-detection procedure. They were required to peck the left key when a 5-second white light had been presented, and the right key when a 10-second light had been presented. These two correct responses were followed by food reinforcement with a probability of .7. Errors, left responses after the 10-second stimulus or right responses after the 5-second stimulus, were initially followed by a 3-second blackout of the chamber. In nine subsequent experimental conditions, errors were followed by food reinforcement with increasing probability while the probability of reinforcement for correct responses was kept constant. The percentage of correct responses decreased as error reinforcement probability increased. A matching model of detection performance, in which discrimination is a joint function of stimulus discriminability and stimulus-reinforcement association, provided a convincing fit to the data and to two sets of published data. The model also fitted published data on multiple and multiple-concurrent free-operant performance. This description of detection performance in terms of matching offers both accurate prediction of complex behavior and measures of discriminability with wide generality.