Extraversion and Neuroticism are two of the Big Five Personality traits identified through statistical means in the last forty years. However, as propensity to positive and negative emotion, what they represent can be usefully and straightforwardly mapped on to underlying biological systems governing approach and incentive reward, on the one hand, and threat and anxiety, on the other. Want to support this channel?
Self Authoring: http://selfauthoring.com/
Jordan Peterson Website: http://jordanbpeterson.com/
Reading List: http://jordanbpeterson.com/2017/03/great-books/