Analysis of single trials in Pigeons' timing performance

Response distributions of pigeons on the peak procedure, averaged over many trials, were well fitted by a Gaussian function plus either a straight line or a ramp. But, each of 11 distributions analyzed showed a systematic positive skew. Response distribution on individual trials showed break-run-break patterns with abrupt transitions in the rate of responding. Within the run phase was an inner run phase at yet a higher rate. Intercorrelations among the starting time, ending time, middle, duration, and rate of the run showed a similar pattern in the outer and inner runs. A positive correlation between starting and ending times suggests variance across trials in clock speed, delay to start the clock, or expected time of reward. A negative correlation between starting time and duration suggests variance across trials in the threshold or thresholds to start and end the run.