Paul Costa is a psychologist known for his work on the Five-Factor Model of personality, which includes openness, conscientiousness, extraversion, agreeableness, and neuroticism (OCEAN).
This is a model that describes human personality traits using five broad dimensions. It's like categorizing all the books in a library into five main genres.
This refers to the trait characterized by outgoingness, high energy, and sociability. It's similar to being the life of the party at social gatherings.
This term refers to one’s tendency towards instability and negative emotions. Imagine someone who always sees the glass as half empty rather than half full.