Temporal factors influencing the acquisition and maintenance of an autoshaped keypeck

Food-deprived pigeons were given briei meals of grain following the presentation of a lignt on a response key. Pecking the key had no consequence Virtually all of the pigeons pecked the lignted key. The number of trials prior to the first peck varied inversely witn the value of the mean interval between light onsets. Trials to criterion was a negative power function of the value of the intertrial interval. The addition of a second stimulus, never followed by food, retarded the acquisition of the keypeck, particularly at short intertriai intervals. During steady state performance, the value of two measures of response strength, rate and probability of responding, increased as a function of the duration of the intertriai interval.