Master of Arts (MA)
Faculty of Science
Robert St. Claire-Smith
This experiment investigated the specificity of encoding the outcomes of instrumental responding with rats. The first part of the study examined the differential outcome effect (DOE) using a 0.5 second flash of light as the outcome differentiator. Acquisition of a two-choice conditional discrimination was not enhanced if Response 1 (R1) in the presence of Stimulus 1 (S1) produced food plus a light flash, and R2 during S2 produced only food. Next, 2/3 of the animals were then trained to make two new responses (R3 and R4), one earning light plus food and the other earning food only. There was no evidence of specific stimulus-reinforcer associations since selective enhancement of performance, by the stimulus of the newly acquired response trained with the same reinforcer did not occur. The brief cue had no reliable effect on level of responding or rate of learning suggesting that this cue is not a successful outcome differentiator.
Newell, Wendy Ann, "An evaluation of outcome differentiation using biologically neutral stimuli" (1990). Theses and Dissertations (Comprehensive). 585.