Date of Award


Document Type


Degree Name

Master of Arts (MA)



First Advisor

Kenneth A. Deffenbacher

Second Advisor

C. Raymond Millimet

Third Advisor

Evan Brown


An experiment is reported in which student subjects attempted to discover a principle by pairing number and letters. Seven groups of subjects varied on two dimensions, proportion of positive instances sampled and degree of restriction in choosing number-letter pairs. It was found that subjects who sampled a higher proportion of positive instances were more successful that those sampling a lower proportion. Furthermore, subjects who were unrestricted in their choice of number-letter pairs, because they sampled a higher proportion of positive instances, performed more efficiently than subjects who were restricted and sampled a lower proportion of positive instances. Finally, when both restricted and unrestricted groups were matched for proportion of positive instances sampled, performance was found to be similar. It was pointed out that there is a need in future research on problem solving to match treatment groups for proportion and positive instances sampled.


A Thesis Presented to the Department of Psychology and the Faculty of the Graduate College University of Nebraska at Omaha In Partial Fulfillment of the Requirements for the Degree Master of Arts.

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Psychology Commons