Raymond Bernard Cattell (20 March 1905 – 2 February 1998) was a British and American psychologist, known for his psychometric research into intrapersonal psychological structure and his exploration of many areas within empirical psychology. These multifaceted areas included: the basic dimensions of personality and temperament, the range of cognitive abilities, the dynamic dimensions of motivation and emotion, the clinical dimensions of abnormal personality, patterns of group syntality and social behavior, applications of personality research to psychotherapy and learning theory, predictors of creativity and achievement, and many multivariate research methods including the refinement of factor analytic methods for exploring and measuring these domains. Cattell authored, co-authored, or edited almost 60 scholarly books, more than 500 research articles, and over 30 standardized psychometric tests, questionnaires, and rating scales. According to a widely cited ranking, Cattell was the 16th most eminent, 7th most cited in the scientific journal literature, and among the most controversial psychologists of the 20th century.As a research psychologist, Cattell was devoted to the scientific pursuit of knowledge through rigorous research. He was an early proponent of using factor analytic methods instead of what he called ""subjective verbal theorizing"" to explore empirically the basic dimensions of personality, motivation, and cognitive abilities. One of the results of Cattell's application of factor analysis was his discovery of no fewer than 16 separate primary trait factors within the normal personality sphere alone (based on the trait lexicon). He called these factors ""source traits"" because he believed they provide the underlying source for the observable ""surface"" behaviors we think of as personality. This empirically-derived theory of personality factors and the multidimensional self-report instrument used to measure them are known respectively as the 16 personality factor model and the 16PF Questionnaire (16PF).Although Cattell is known for identifying and elucidating dimensions of personality, he also undertook a programmatic series of empirical studies into the basic dimensions of other psychological domains: intelligence, motivation, career assessment and vocational interests. Cattell theorized the existence of fluid and crystallized intelligence to explain human cognitive ability, investigated changes in Gf and Gc over the lifespan, and constructed the Culture Fair Intelligence Test to minimize the bias of written language and cultural background in intelligence testing.