Sociability, assertiveness, excitement-seeking and emotional expression characterise:

1. The Big Five factors are separated by their defining facets. 2. Extroversion is characterized by sociability and assertiveness. 3. It also includes excitement-seeking and emotional expression. 4. Conscientiousness is characterized by competence and self-discipline instead. 5. So the sociability cluster identifies extroversion. _Source: OpenStax Psychology 2e (CC BY 4.0), Ch 11 'Personality', sections 11.1-11.9_