3 students and Dr.John Lefebvre

Senior Theses: 1996-1997

Judgment of Eye Level in Pitched Visual Environments
Kristin Burris, Brian Grigg, Katherine Harding, & Jeff Wood
Faculty Advisor: Don Scott, Ph.D.

Subjects determined eye level in both illuminated and dark conditions by pointing with a laser pointer to their visually perceived eye level (VPEL) in the pitched environment. In experiment one, measurements were recorded at -20, 0, and +20 degree pitches with the subject's head held stationary. Perceived eye level was judged more accurately in the dark conditions versus the illuminated conditions, but the data was not found to be statistically significant. Subjects were then reevaluated in the same environment, with and without head restraint. In experiment two, there was statistical significance with pitch and head restraint individually, but no significant interaction was found between the two conditions.

The Development of Behavioral Units in Free-Operant Schedules
Ellen Burriss, Cindy Chadwick, Elizabeth Hubbard
Faculty Advisor: Alliston K. Reid, Ph.D.
These data have been published in the Journal of the Experimental Analysis of Behavior. 

Four rats were trained to press two-response sequences on two separate levers. Two sequences involved homogeneous sequences (LL and RR) and two sequences involved heterogeneous sequences (LR and RL). The purpose of this experiment was to examine the development of behavioral units. The experiment consisted of three different conditions which combined together to form the larger experiment. Free-operant schedules were used to provide reinforcement. Condition 1 utilized two different probabilities to reinforce the subjects. A low probability of reinforcement was used with the homogeneous sequences and a high probability was used with the heterogeneous sequences. Condition 2 introduced a tone after every second lever press. The reinforcement probabilities were still used along with the free-operant schedule. Condition 3 did not use the tone that was present in the previous condition. The transition probabilities were determined following the conclusion of each conclusion. It was found that a behavioral unit did form and the matching law was demonstrated.

Behavioral Units as a Function of Learning
Kate Wilson, Mary Mac Williams, & Spence Cummings
Faculty Advisor: Alliston K. Reid, Ph.D.

Four feral pigeons were exposed to two schedules. One was an FCN (Fixed Consecutive Number) and the other was an FCNSW (Fixed Consecutive Number-Switch). Using a Latin square design to control for order effects, three birds were administered different values of both schedules. The desired number of pecks, N, was the following for FCNSW: 2, 4, 8, 16. The two schedules were compared to determine if the behavioral unit (left-middle peck) in the FCNSW schedule had an effect on the distributions in comparison to the FCN schedule. The data obtained were not sufficient to draw any strong conclusions. However, it supports the hypothesis that behavioral units function as an aid in learning.