501. The big five

 In psychology there is the notion of the ‘Big Five’ personality traits: extraversion, neuroticism, conscientiousness, agreeability, and intellect/openness. These five categories are customary and widely used, though the characterisation of each varies (Digman 1990, 421-7).

 Extraversion has been associated with ‘surgency’, action orientation, assertiveness, power, risk taking. positive emotionality and interpersonal involvement.

Neuroticism: emotional instability, emotionality, anxiety, depression, affect and lack of adjustment.

Conscientiousness: will to achieve, dependability, task interest, conformity, superego strength, prudence, work, constraint and self-control.

Agreeability: friendliness, conformity, compliance, likeability, love, sociability, socialisation, the opposite of paranoia, hostility, indifference, self-centeredness, spitefulness and jealousy.

Openness: inquiring intellect, intelligence, culture, independency.Variation and ambiguity of interpretation are greatest concerning this category of openness/intelligence (Digman 1990 433).

 Clearly there are interacions between the traits, and shared inclinations. Thus, loving interacts negatively with neuroticism and positively with agreeableness, though less than one would have expected (Digman 1990, 433). Extraversion can be but is not necessarily immoral. It is the basis of daring. courage. taking risks and exploration that pushes ambitious entrepreneurs, discoverers, politicians, and scientists. Plato offered the metaphor of reason as a charioteer controlling two wild horses, of desire and ‘Thymos’, the urge to manifest oneself, the same perhaps as extraversion. It can be combined with conscientiouseness and/or agreeableness. It is morally disastrous when combined with narcissism or sociopathy.

 Nettle (2006) asked the question how it is possible that differences in personality can persist. Would evolution not have favoured adaptive traits and selected out the maladaptive ones? His answer is that every trait has costs and benefits, and what what is adaptive depends on the selection environment, which has varied much in evolution, in war and peace, economic conditions, climate, natural disasters etc. In one condition one trait or combination of traits is most adaptive and under other conditions another, and as a result difference is maintained

 Nettle illustrated this with examples from animal worlds. When there is no rain, for a certain kind of bird, seeds are dry and hard, and the bird needs a strong beak of a certain shape, and when it rains much, the seeds are soft and other beaks suffice. Also applying to humans is the principle that when there is prosperity, with ample resources, there are many competing individuals, and being strong and aggressive is adaptive, and when there is scarcity there is less competition, and it is not adaptive to incur the metabolic costs and the risks of aggressiveness. Perceptiveness of threat may be adaptive, favouring neuroticism, but also restricts endeavour and daring needed for survival, depending on the circumstances. Openness/intelligence favours the seeking of novelty, perception of threat and opportunity, making mappings between disparate domains, and creativity, which as a male characteristic is valued by females But it can yield too much reflection and doubt, and too little action. It is correlated with pychosis and schizophrenia, yielding reduced reproduction. For sexual reproduction, strength, size, demonstrativeness.and aggression of males, in the trait of extraversion, may attract more females, but being small and creeping unobtrusively into nests, cuckold and procreate on the sly is an alternative. Fitness can be enhanced by a capacity to free ride, break rules and cheat on others.(Nettle 2006 627) .For this one needs high mobility and migration to escape censure and punishment. All this can be part of conscientiousness.

   Digman, J.M. 1990, ‘Personality structure: emergence of the Five-Factor model’, Annual Review of Psychology, 41 417-40.

  Nettle, D 2006, ‘The evolution of personality variation in humans and other animals’. American Psychologist 61/6 622-31