Lewis R. Goldberg is an American personality psychologist and a professor emeritus at the University of Oregon. He is closely associated with the lexical hypothesis that any culturally important personality characteristic will be represented in the language of that culture. This hypothesis led to a five factor structure of personality trait adjectives. When applied to personality items this structure is also known as the five-factor model (FFM) of personality. He is the creator of the International Personality Item Pool(IPIP), a website that provides public-domain personality measures.