The shaping of personality: genes, environments, and chance encounters.

I started my career as a clinical psychologist with an interest in personality assessment. But a loss of faith in psychoanalytic theory, projective tests, and clinical case studies in general led to a shift in my interests to personality research. Subsequent jobs at research institutes and universities allowed me to indulge in science. I developed the trait-state concept and its application in tests for affect measurement. For 10 years I did experimental research in the field of sensory deprivation. The sensation seeking idea and tests evolved from this work but soon expanded to many other areas. Research in the biological basis of sensation seeking started with genetic and psychophysiological research, but research conducted in other laboratories also pointed to a psychopharmacological basis for the trait. Over the last several decades, I have formulated a psychobiological model for personality. I have used factor analysis and the biosocial model to develop an "alternative-five" factorial trait structure for personality.