Two personality dimensions Mapmakers can tell us a lot by using two axes (north-south and east-west). Two primary personality factors (extraversion-introversion and stability–instability) are similarly useful as axes for describing personality variation. Varying combinations define other, more specific traits (from Eysenck & Eysenck, 1963). Those who are naturally introverted, such as primatologist Jane Goodall, may be particularly gifted in field studies. Successful politicians, including former U.S. President Bill Clinton, are often natural extraverts.