A comparison between the block clock and standard autoshaping procedures

Pigeons trained through block clock procedures pecked more often both throughout and at the end of a cycle of four colors than did those trained with standard autoshaping. Total pecking in the former experiment correlated positively with the number of stimuli, contrary to response-dependent, or operant, procedures. The difference in the final clock segment was most striking, as conditions then were identical. The presence of clock stimuli apparently has opposite effects for the two conditioning methods.