Though a widespread advocacy exists for the use of learning style instruments in adult education, accurate measurement and interpretation using existing instrumentation have proven problematic. Additionally, relatively little attempt has been made to empirically reconcile the different theoretical and conceptual frameworks underlying these instruments. The purpose of this study was to examine the dimensionality, reliability, and construct validity of a cognitive learning style semantic differential instrument, the Cognitive Preference Pattern Indicator (CPPI), and at the same time to examine three instruments commonly used with adults for assessing cognitive learning style, the Myers-Briggs Type Indicator (MBTI), the Success Style Profile (SSP), and the Gregorc Style Delineator, with respect to factor structure and shared learning style constructs. Over 1900 protocols from 1411 adults were used in the analyses. The examination of the CPPI produced clearly acceptable internal reliability coefficients on all scales and relatively strong evidence of construct validity in the internal and comparative factor analyses. Separate internal factor structures were examined for each instrument. Though not all of the other instruments' internal structures completely supported their respective theoretical bases, enough internal structures emerged for an analysis of common constructs. A combined factor analysis of the four instruments yielded a robust three factor solution which was consistent with an information processing model framework for clearly describing individual differences in regard to cognitive learning styles. The clear relationships of this model revealed strong empirical support to the theoretical bases of the CPPI and offered the adult education community a simple, valid, and profound conceptualization of cognitive learning styles. / Ph. D.