On the Curious History of the Big Six: Variable Selection and "Moral Exclusion" in the Formation of Fundamental Personality Models

The Big Five became the foremost model of personality-trait structure in the last three decades, but was formed out of item/variable selections that partially or totally omitted dispositional content related to morality, ethics, integrity, and honesty. Such morality-relevant content has, for several reasons reviewed, extreme importance within the dimension of dispositional tendencies. Previous histories of the Big Five ignore details that account for this pattern of moral-content exclusion, exclusion that tended to impede identification of a key factor in a Big Six or HEXACO model. Here, a set of frequently referenced and highly morality-relevant adjective concepts are identified, based on ratings by 10 judges. The treatment of these concepts enables a tracing of the specific routes and rationales by which exclusion (and partial inclusion) operated in key lexical studies of the archaic period of lexical studies (up through 1993; in English and German), that reveals how variable-selection decisions by early investigators tended to impede identification of an important dimension of personality. Recommendations are offered for future personality-structure research.