Tuesday, January 06, 2009

Personality traits: evolutionary perspectives

I have been reading and enjoying The Handbook of  Personality Psychology by Hogan et al, and found the chapter written by David Buss particularly useful.

Here I would like to expand on the idea and while buss explicitly does not want to indulge in a discussion of a few psychological tendencies and associated behavioral class acts; I would like to walk exactly that particular path.

First to recap,

Humans, like other organisms, can be viewed as organized structures that exist in their present form because of a long history of natural selection, operating over millions of years. Each one of us owes our existence to a long and unbroken line of ancestors who successfully solved problems posed by survival and reproduction in our evolutionary past. Therefore, human structures, as well as human psychological mechanisms, at some fundamental level of description, can be analyzed in terms of the problems they solve.

But "survival" and "reproduction" are broad categories, each subsuming a large and complex array of subproblems. To the extent that the evolutionary psychologist can identify the nature of the specific problems that humans have evolved to solve, she or he has some advantage over the nonevolutionary psychologist in discovering the nature of human nature.

Buss then goes on and breaks the survival and reproduction into many component and also adds genetic investment to the mix. I parse the same data in my own way and generate the hypothesis that the most important concern of any living organism, and especially humans are survival, genetic investment and reproduction.

Survival behavioral tendency can be further split in three parts: one pure survival as in escape from predators or death; I'll refer to this as Foes! the second concerns growth or acquiring resources necessary for thriving and I;ll call this Food. The third maintaining one'd edge in avoiding foes and finding Food by building alliances with con specifics. I'll call this Friends. Thus survival is characterized by the three F's of Foes, Food and Friends!

Genetic investment can be split into two K's that of Kids and Kins. The first tendency that of Kids is concerned with issues of parental investment and care of offsprings.the second that of Kin is concerned with how to help other genetic related individuals at minimal cost to self such that maximum fitness ensues.

Reproduction can be split into three parts that of mate selection, that of mate attraction and that of mate retention. I'll call these the three S's of reproduction(Sex is *NOT* one of them!). The first task is to Select the right mate; the second task is , that once you have zeroed in on a suitable mating partner, you have to court and attract the partner, I call this function Seduce; the final task, especially in long-term pair bonded species like Humans is to guard or retain the mate, I call this Securing the mate.

What I propose is that given these Eight tasks ( 3 survival, 2 investment and 3 reproductive tasks ) that each species has to solve, each specie would evolve some mechanism to solve these problems that are species-typical; however there would be individual variation to the extent that the extent to which an individual organism is driven by that particular conscious motivation/ behavioral tendency and gets into environments and situations that trigger that particular task would determine the psychological mechanism that drives that individual.

To make things more clear , what I am proposing is that there are bound to be individual differences in the relative importance of these psychological mechanisms for an individual- thus a human may be primarily driven by mate selection concerns at a particular age- while another may be forever primarily concerned with safety, security etc- and this would be the first factor that would lead to individual variation in personality. Moreover, I am proposing something radical, that depending on the environment, there may be two extreme types of responding to each of these tasks- and the second most important variation that we get from person to person - is in whether one habitually and instinctively (genetically determined) responds in one way or the other as one faces the task and whether or not one factors the environment and context in which the task demand is made or whether ones behavioural tendency is fixed and inflexible.

To take by way of an example, lets us focus on the Kids part of genetic investment. It has been well documented that their are two types of parental strategies r-type and K-type; now a species may have predominantly K-type investment strategy, but within the species individual organisms would differ in their reproductive strategy around the mean in K-type and r-type directions. thus, Humans exhibit predominantly K-strategy, but Africans show more r-type and Asians more K-type. It is equally well documented that these r-type and K-type strategies are actually responses to the external environment (food abundant, predictable , stable environment etc) and thus, though a species has a set point, there is enough individual variation such that in changing environemnetal conditions at least one sub type is able to thrive and survive and reproduce and invest!

To take another example from Buss, Absence of father leads to short term mating strategy in daughters (amongst other things like premature puberty etc) and this environmental facyor may be the most important environment variable as related to Securing task of retaining the mate; if one sees the father as absent from home, one may think its wise to go for a short term mating strategy as the culture is one that encourages low stability of pair bonds; this might be a justifiably welcome strategy; on the other hand it might be genetically the case that someones set point is set towards short-term relationships.

I will now claim that the eight personality traits I had outlined earlier are directly related to these eight evolutionary task (see here for another slightly different list of the eight tasks ) that one faces- and more so are mapped one-on-one with the same ordered mapping!


  1. Foes (survival 1) : A behavioral tendency to be on the lookout for foes / troubles leading to Neuroticism trait. The extremes of courage/calmness and fear/anxiety  are driven by what type of environment one lives in - whether it is full of dangerous objects or not so! One prediction is that those high in N should have more Phobias and vice versa. 
  2. Food (survival 2):A behavioral tendency to acquire resources leading to Conscentiousness. The extremes of ambition/ covetousness and laziness/ easy-going are driven by whether the environment is abundant in resources or lacking thereof! One prediction is that those high in C should be more readily diagnosed with OCD and vice versa.
  3. Friends (survival 3):A behavioral tendency to form alliances leading to Extraversion. The extremes of sociability and seclusion dependent on some environmental factor (like how important is community interference in day to day activity) . Might be related to mean group size (150 in humans)
  4. Kids (investment 1)   A behavioral tendency to invest in ones offsprings leading to Agreeablness. the extremes of care/ empathy vis-a-vis apathy/ psychopathy may be driven by the same concerns that decides whether to go for r-strategy or K-strategy.
  5. Kins (investment 2) : A behavioral tendency to help one kins leading to Conformity / Rebelliousness: Here it is instructive to note that older siblings are generally conformists while younger siblings are rebellious - thus age-order and environmental variable may decide whether one would be conformist or rebellious and this somehow affects your behavior towards sibling and his/her reproductive fitness. Also, irrespective of your birth order in the family (kin) , due to variation, some may be genetically predisposed to be conformists and other rebellious!
  6. Selecting (reproduction 1) : A behavioral tendency to judge others intentions etc accurately and thus determine who is a suitable candidate for mating/trusting  leading to Trust/Defensiveness. The extremes of trust and suspicion may be adaptive in environments differing with respect to levels of promiscuity; in a highly promiscuous and cheating/ cuckolding environment it may pay to be suspicious.     
  7.   Seducing (reproduction 2): This behavioral tendency of intra sexual competition can be broken into three components: i) Testing against own sex con specifics(building better muscles for men) ii) Embodying preferences of opposite sex (Chauvinism in case of Males) and the third I havent been able to figure yet!! The extremes of too much effort/activity  in seducing as against the extreme of being dull/boring and uninterested in other sex leads to the dimension of Activity
  8. Securing (reproduction 3) : A behavioral tendency towards sociosexuality;At one end of this dimension are individuals who are "restricted" in sociosexuality—they require more time, attachment, and commitment prior to entering a sexual relationship. At the other end are those who are "unrestricted" in sociosexuality—they require less time, attachment, and commitment prior to sexual intercourse. These extremes may lead to the trait of Masculinity- Feminity in how one guards and forms a pair bond.

I would thus end my argument; to me the eight stage process is compelling- I am sure with each passing day there are more converts to that developmental and evolutionary eight stage theory.

References: Buss, D. M. (1997). Evolutionary foundations of personality. In R. Hogan, J. A. Johnson, & S. R. Briggs (Eds.), Handbook of Personality Psychology (pp. 317-344). New York: Academic Press..

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