Second, a variety of personality classifications have been proposed over the past century, but in the 1980s they were integrated in a consensus taxonomy, the Five-Factor Model (FFM). The FFM recognized that personality is ordered hierarchically from a large number of specific traits to five general characteristics (Digman 1994, Goldberg 1993, Markon et al. 2005). These “Big Five” traits are neuroticism, extraversion, conscientiousness, agreeableness, and openness to experience. Importantly, the FFM can be further reduced to three dimensions of negative emotionality, positive emotionality, and disinhibition versus constraint that form the next level of the personality hierarchy (Clark & Watson 1999, Markon et al. 2005). This “Big Three” model is used in studies of temperament as well as personality, although disinhibition is often labeled as effortful control in the child literature (Caspi & Shiner 2006, Rothbart & Bates 2006). The Big Five and Big Three schemes are closely related, with neuroticism being essentially identical to negative emotionality and extraversion corresponding to positive emotionality (Clark & Watson 1999, Markon et al. 2005); we refer to these two dimensions as neuroticism/negative emotionality (N/NE)
