Interpersonal cognitive differentiation measures as predictors of written communication ability

Numerous instruments have been proposed to measure interpersonal cognitive differentiation or complexity. Unfortunately, previous research has shown these measures to be only marginally related (O'Keefe & Sypher, 1981). This investigation sought to unravel this methodological tangle by providing further evidence bearing on the comparative validity of several measures of cognitive differentiation as predictors of two written persuasive tasks: a fund‐raising task and a job application letter task. Regression analyses indicated that the Ziller, Martell, and Morrison (1977) self differentiation measure and Crockett's (1965) Role Category Questionnaire were both significantly related and significant predictors of the criterion variables, while Bieri et al.'s (1966) measure was virtually unrelated to any of the study variables.