| Correlate as named by investigator | People investigated | |
| Finding | Extraversion | Adult general public, 39 nations, 1972-1998 |
| Finding | Extraversion | Adult general public, 39 nations, 1972-1998 |
| Finding | Extraversion (Eysenck) | Adults, general public, 30 countries, 1974-1999 |
| Finding | Extraversion vs introversion | Normal adults, general public, 30 countries, 1977-1997 |