As the field of psychology developed, personality research became more refined and competing, but related frameworks developed—some with as many as 16 factors and others with as few as four. But, somehow the number five kept coming up. Robert Costa and Paul McCrae developed the so-called Five Factor Model in 1987, and Lewis Goldberg developed the “Big Five Model” in 1993, both using the same core personality factors: openness, conscientiousness, extroversion, agreeableness, and neuroticism. Since then, these Big Five personality traits have been studied and validated time and time again by many researchers over decades.
