Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Jack L. Michael

Second Advisor

Dr. Richard Malott

Access Setting

Masters Thesis-Open Access


Using a discrete-trial, two-component multiple schedule, pigeons were required to complete a fixed-ratio in the presence of stimuli correlated with different probabilities of reinforcement (Experiment 1), or different amounts of reinforcement (Experiment 2). The amount of separation of graphed median latencies to the onset of the two stimulus conditions as a function of the different reinforcement conditions was investigated in relation to various fixed-ratio values. It was found that previous researchers had chosen an optimal fixedratio size; larger ratios produced greater separation between median latencies, but at the expense of increased session-to-session variability, while smaller ratios failed to produce median latency separations that were useful in evaluating the effects of the other variables.