Publication Date


Document Type


First Advisor

Hershberger, Wayne A., 1931-

Degree Name

M.A. (Master of Arts)

Legacy Department

Department of Psychology


Sound--Psychological aspects; Animal behavior


Previous studies have shown that a variety of long-term behavioral effects can be produced by manipulating an animals early sensory experience. One general finding has been that increased early stimulus input leads to greater exploratory behavior in adulthood. However, this finding has been based on studies which have only manipulated early visual and tactual stimulation. The present study varied early auditory stimulation in an attempt to extend this finding to another sensory modality. Each of four groups of twenty rats were exposed to one of four conditions of early auditory stimulation for 14 days, beginning at weaning. Subsequently, the animals' levels of exploration were assessed in both an auditory and a tactual preference test. The design of the experiment was a 4x2x2x2 split-plot, the four factors being: Auditory Stimulation Condition (sound restriction; single frequency, variable intensity; systematically variable frequency and intensity; randomly variable frequency and intensity), Test Type (tactual test vs. auditory test), Testing Sequence (tactual test first vs. auditory test first), and Time Block (first half of each test vs. last half of each test). During each 10 min. test, the animals were observed at 30-sec. intervals to determine which of five differentially variable sections of the testing apparatus they occupied. The sections were numbered along an ordinal scale of stimulus variability. For each observation the number of the section occupied was recorded. The mean of these numbers for each animal served as a measure of exploration, and the standard deviation served as a measure of activity. Each measure was subjected to an analysis of variance. The results showed that the animals which had experienced the greatest degree of variation during controlled rearing were the least exploratory and most active of all animals. This seems to indicate that early auditory experience produces effects which differ from the effects of early stimulation in other sensory modalities. An alternative interpretation in terms of Activation Theory is also presented.


Includes bibliographical references.||Includes illustrations.


46 pages




Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type