Sidney J. Blatt was a major figure in psychology and psychoanalysis. As a psychoanalyst, he was both a master clinician and a leading researcher in personality theory, personality development, psychopathology, personality assessment, and psychotherapy. Best known for his two-configurations model of personality, he was the author or coauthor of more than 250 articles and 18 books and monographs. This paper describes his three main contributions to our understanding of personality, both normal and abnormal, and clinical change: the two-configurations model, the cognitive morphology of mental representation, and the theory of internalization. The implications of these three concepts for psychotherapy research are delineated. Also discussed in this paper are the formative experiences, personal and intellectual, that influenced his ideas. Early experiences of loss are highlighted as crucial to Blatt’s understanding that some experiences of depression, and therefore some aspects of personality development and functioning, are rooted in relational issues, not only loss but attachment more generally, rather than in issues of guilt, self-criticism, and self-definition.
Two-configurations model; Cognitive morphology; Mental representation; Internalization; Object relations; Personality assessment