Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Paul Mountjoy

Second Advisor

Dr. R. Wayne Fuqua

Third Advisor

Dr. Jack Michael

Access Setting

Masters Thesis-Open Access


This experiment examined auditory stimulus control in a totally darkened as opposed to an illuminated chamber. All subjects (pigeons) were trained to keypeck in the presence of only a dimly lit green keylight, which was faded until responding was reliably occurring in a totally darkened chamber. When behavior stabilized under a Variable Interval (VI) 30 second schedule of reinforcement in a darkened chamber, subjects were divided into two groups for discriminating training. A Multiple VI 30 second Extinction (EXT) schedule was in effect, with 1-minute components separated by 5-second time-outs. The discriminative stimulus correlated with the VI component was a pulsing tone; for the EXT component it was a continuous tone. No tone was present during timeout. One group underwent discrimination training in a darkened chamber, the only illumination being a hopper light during grain presentation. The other group underwent identical discrimination training, except that the chamber was illuminated by the houselight at all times other than grain presentation. Pigeons trained in a darkened chamber showed higher asymptotic levels of auditory stimulus control than those trained in an illuminated chamber. The results suggest that visual stimuli provide concurrent sources of reinforcement which can attenuate the control exerted by auditory stimuli. In a totally darkened chamber these visual stimuli are eliminated.