We used 16 PF Questionnaire to investigate differences in Extroversion according to the Cold-Hot astrological scale (even-odd signs) in 589 Brazilian university students of both genders, ages ranging from 19 years and 6 months to 51 years and 1 month, differentiating them among knowledgeable (208) and non knowledgeable (381) of astrology, by the description of three characteristics of the solar sign. For part of the group (266) it was given the suggestion "This is a research on astrology" , while for the other part (323) it was said that it would be "a research about personality" . The ANOVA did not reveal astrological differences (p>0.10) in none of the groups. The knowledgeable ones presented larger Extroversion compared to the non knowledgeable ones (p=0.01). This difference was due to the results of Hot signs participants (p=0.0007), indicating the confirmation of larger susceptibility to the outside information about their personalities.
personality; self-concept; astrology; 16 PF questionnaire; attribution of causality