The lexical hypothesis is a concept in personality psychology and psychometrics that proposes the personality traits and differences that are the most important and relevant to people eventually become a part of their language. It goes further to suggest that the most important concepts in personality become single descriptive words in a language. By using language as a resource and a sample a full spectrum and taxonomy of personality traits can be assembled. This concept has been around since the 1800s and many different methodologies have used the lexical hypothesis to develop personality taxonomies and lists. In 1936 Gordon Allport and Henry Odbert used the lexical hypothesis to conduct one of the most important and seminal studies in personality psychology. They used the dictionary to identify nearly 18,000 terms that described personality, behaviors, and traits. Raymond Cattell used computers in the 1940s to analyze Allport and Gordon's terms and condensed them into 16 source traits or factors eventually developing the 16PF Personality Questionnaire which is still used to this day. Warren Norman reduced Allport and Gordon's terms to 3,000 and eventually identified five overarching factors that encompassed most of human personality. Other researchers did the same and the Big Five (hyperlink?) personality factors became the most inclusive method of measuring personality. The Big Five are openness to new experience, conscientiousness, extraversion/introversion, agreeableness, and neuroticism. (OCEAN) and research has shown between the five 80% of personality variance can be accounted for.