College of Arts & Sciences

Date of Award


Document Type

Research Project Report

Degree Name

Master of Arts (MA)


Behavioral Science

First Advisor

J. Greenspan, Ph.D.

Second Advisor

James Olson, Ph.D.

Third Advisor

Robert Rothstein, Ph.D.


The effects of three different schedules of reinforcement on generalization in rats were investigated. The rats were trained to bar press in the presence of a 2000 hz tone and then participated in tone/no tone discrimination training. Upon completion of discrimination training, the rats were assigned randomly to one of three groups, a FR 10 group, a FR 25 group or a FR 50 group. After seven days on these schedules, generalization testing was started. Six days of generalization testing were done with a 31.5 minute tape of 7 tones in a random sequence. The tones for which the subjects' responses were recorded were: 250 hz, 500 hz. 1000 hz, 2000 hz, 4000 hz, 8000 hz and 16000 hz. The FR 10 group produced the only generalization gradient around the training frequency. The FR 25 and FR 50 groups had their gradients centered about the 1000 hz tone. Generalization gradients were steepest earlier in generalization testing and were flatter as the extinction condition continued. The larger the ratio of the reinforcement schedule the faster the gradients flattened. Thus if the FR schedule is of larger ratio, generalization is evident immediately. The results also indicate that as the density of reinforcement decreases, generalization increases greatly.



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