Factor analysis of a questionnaire on imagery and verbal habits and skills.

Abstract

The Individual Differences Questionnaire contains 86 items designed to measure imaginal and verbal thinking habits and skills. To study the structure of this test, a series of item factor analyses were performed. Data from 3 independent samples of university students, each with n > 300, were analyzed in parallel, and the results were compared across samples to assess factor reliability. When the analyses were restricted to 2 factors, the solutions were essentially identical across samples, and the factors corresponded closely to the original (theoretically defined) verbal and imaginal scales. Solutions with 56 factors also proved replicable and provided a more refined description of the test''s structure. The 6 factors were designated as: good verbal expression and fluency; habitual use of imagery; concern with correct use of words; self-reported reading difficulties; use of images to solve problems; and vividness of dreams, daydreams and imagination. A few sex differences also emerged. The 6-factor solution suggests a modified interpretation of the original scales and may have other theoretical implications for the study of imagery.