Psychology ETDs

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This experiment was design0d to test two implications derived from the hypotheses of acquired distinctiveness and equivalence of cues, and to determine the way in which similarity among external stimuli and distinctive vs. common mediating cues, interact to affect the learned distinctiveness or equivalence of cues. It was predicted from the acquired distinctiveness hypotheses that relative]y greater positive transfer would result when distinctive mediating responses were attached to highly similar stimuli than when these same responses were attached to stimuli that were initially low in similarity. A parallel prediction, derived from the acquired equivalence hypothesis, was that negative transfer would be relatively greater when common mediating responses were attached to stimuli low in initial similarity than when these responses were attached to stimuli which were high in initial similarity.

Ten volunteer is were assigned at random to each of the eight experimental conditions. The experiment was conducted in two parts: a preliminary pretraining task and a subsequent motor-switching transfer task. In Task I, Ss received one of four types of pretraining with stimuli which were either high or low in intralist similarity. In the first type of pretraining, Ss were required to attach distinctive two-syllable adjectives to four different light intensities. A second type of pretraining required Ss to attach one two-syllable adjective to the two lights of greatest intensity, and a second adjective to the two lights of least intensity. In the third type of pretraining, Ss were required to ''observe and discriminate" among the four light intensities of a set, but were not required to attach any labels to them. The fourth condition involved no pretraining, and Ss assigned to this condition began the transfer task without any prior practice with the stimuli. Following pretraining, were immediately given a transfer task, involving the same stimuli they had experienced during pretraining, and which required them to learn to press a different switch to each of the task stimuli.

Analyses of the data from the motor-switching transfer task in terms of the number of correct responses per trial and the distribution of errors over all trials showed that Ss given distinctiveness pretraining made more correct responses and fewer errors on the transfer task than any of transfer pretraining conditions. It was also found that Ss pretrained and tested with low similarity stimuli made more correct responses and fewer errors than Ss pretrained and tested with high similarity stimuli. There was no interaction between type of pretraining and level of intralist stimulus similarity. The results were interpreted as being inconsistent, with the initial predictions from the acquired distinctiveness and acquired equivalence of cues hypotheses.

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First Committee Member (Chair)

Harry C. Ellis

Second Committee Member

Frank Anderson Logan

Third Committee Member

David Theodore Benedetti



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