Effects of stimulus complexity and induced arousal on paired-associate learning

Abstract

Three experiments on paired-associate learning were carried out, with disyllabic male first names as response terms. Exps. I and II, in which visual patterns served as stimulus terms, showed significantly fewer correct recalls when stimulus terms were more complex or incongruous. Familiarization of half of the stimulus terms before the first training trial made no appreciable difference, which casts doubt on the attribution of the effect to differences in arousal value. The effect seemed more likely to be due to presence or absence of symmetry. White noise was used in Exp. II as a means of manipulating arousal. Recall was impaired when S s were subjected to 72 db white noise during training and testing, and there was some indication that recall might be improved by 58 db white noise. In Exp. III, stimulus terms were single adjectives, homogeneous double pairs of adjectives, and heterogeneous double pairs. One quarter of the items were learned under white noise and tested the next day under white noise, one quarter learned without white noise and tested under white noise, one quarter learned under white noise and tested without white noise, and one quarter learned and tested without white noise. Five groups of S s had different intensities of white noise ranging between 35–75 db. It was found that recall, both on the training day and on the test day, was worse with heterogeneous double than with homogeneous double stimulus terms but equal with homogeneous double and single stimulus terms, corroborating the hypothesis that the symmetry factor had been responsible for the results of Exps. I and II. On the training day, there was significantly less recall with white noise than without white noise. On the test day, items learned under white noise the day before were recalled significantly more often than others, although there was a significant interaction between presence of white noise on training and test days. No significant effect of white noise during the test trial appeared. Variations in white-noise intensity had no significant influence.