Voice inflection and the auditory von Restorff effect.

Abstract

Numerous research projects have revealed that an "isolated" or distinct item in a homogeneous list is recalled more readily than its non-isolated counterparts. This isolation phenomenon was first investigated by von Restorff and has since become known as the von Restorff effect. Until recently, the research projects were conducted using visual stimuli. However, Arbogast has shown that the von Restorff effect also exists for auditory stimuli. The purpose of this study was to investigate the possibility of a von Restorff effect for voice inflection which involves a subtle usage of auditory stimuli. In this study eighty subjects learned the order of a nine-item serial list by the anticipation method to a criterion of two perfect trials. The list consisted of five-letter nouns that occur with equal frequency in English usage. The selected words occur more than fifty but less than one hundred times per one million written words. The subjects for this experiment were forty males and forty females enrolled in Introductory Psychology at Emporia State University. The subjects were divided into male control and experimental groups and female control and experimental groups with each group consisting of twenty subjects. The control subjects listened to the serial list items which were taped in a female voice at a sound intensity level of less than seventy decibels. The same taped list at the same sound intensity level was presented to the experimental subjects except that the number six serial item was vocally inflected to a level of seventy-five decibels. Statistical significance was evaluated through the use of a 2 x 2 fixed effects analysis of variance. The statistical analysis for serial position six indicated that there was not a significant difference in mean number of errors between the isolated and non-isolated conditions at the .05 level of probability. The data also failed to indicate a significant difference between males and females. However, there was a significant difference between the mean number of errors at the .05 level of probability between the experimental and control groups at serial position three. There were no significant differences between males and females, and there was no significant interaction effect at the .05 level of probability for position three. Also, there were no significant differences demonstrated at the remaining seven serial positions. The results of this study failed to reveal that a significant von Restorff effect occurs when voice inflection is employed in a serial learning task.