Evolutionary psychology of Personality

Evolutionary Psychology of Personality
I. Quick Recap of Key Evolutionary Concepts
Charles Darwin noticed while exploring in the world that there were differences between and within species. While exploring the Galapagos Islands, he observed that there were finches that all had variations in the size of their beaks. He began to study why this was occurring within the one species of the finch and discovered that these changes were happening over a long period of time. Darwin then came up with the concept of natural selection that has a main rule of survival of the fittest. This means that only those that are fit for the environment will live to be able to reproduce and pass on their genes.
Another concept that Charles Darwin came up with was sexual selection. Sexual selection is the idea that males and females have evolved over several generations to maximize reproduction. These changes in the individuals not only include how males and females can better reproduce with one another but also extends to how males compete against other males for the females or how females compete against other females for the male.
Ever since Charles Darwin first came up with the notion of natural and sexual selection, evolutionists have noted variations in behavior and personality within and between different species. Instead of highlighting the similarities in personality, “Solving these adaptive problems involves attending to the differences among people (e.g., differences among potential leaders) rather than the universal features of human nature (e.g. having two legs).” In order for a species to survive, they must be able to determine what weaknesses their competitors have so that they can have some sort of advantage over them. Animals exhibit this personality recognition was well and have demonstrated that they are able to read play signals of other animals versus signals that they want to fight. This advantage benefits the individual because they will have a higher chance of being able to reproduce and pass on their genes. Some other ways in which species use these differences to their advantage is by showing off traits that the other does not possess. There are times when the individuals will even deceive others in an attempt to have an appearance or personality that they are superior to others.
II. Evolutionary Psychology and Personality Psychology
Novel research has been conducted on personality psychology from an evolutionary perspective. Evolutionary Psychology examines the variation between species and seeks to identify specific evolved adaptations and psychological mechanisms that explain human nature. Personality psychology examines the proximate explanations for individual differences between people Buss proposes that personality characteristics may not reflect noise or by products of other adaptations, might have an adaptive function. Viewing personality through the lense of the theory of evolution, Buss proposes four explanations for the variation--differences in personality may be heritable alternative strategies and may be calibrations to fluctuating strategies or thresholds throughout development or personality may reflect contextual differences.
An evolutionary theoretical framework can supplement and enhance current personality theory about the adaptive functions for genetic differences that influence personality, potential proximate mechanisms governing personality structure, aspects of developmental environment should be expected to affect, the degree that individuals should be affected by different environments, and why personality traits are responsive to environmental modulation.
III. The Big Five Personality Traits
Personality is a source that can tell us important social dilemmas faced by our ancestors. The big five personality traits reveal important social landscapes, and the traits themselves reference particular human qualities that influenced evolutionarily behavior for our ancestors. There are well documented sex differences in personality, attributed to differences in male and female reproductive strategies performed in the ancestral environment. For example, traits for dominance and aggression are seen as more beneficial to the reproductive fitness of men, thereby the selection of these traits in women are lower and more relaxed.
Individual variations of these personality traits are theorized to balance along an ever changing optimum dependant on place and time. Research has indicated particular advantages and disadvantages of the five traits, giving clearer indication of the optimal level for each.
Openness
The trait of openness encompasses an individual’s ability to form creative connections between concepts and is associated with artistic ability. In terms of fitness benefits, research has shown that higher levels of openness and creativity are associated with a higher instances of being perceived attractive by the opposite sex, resulting in a greater ability to attract a mate. <ref name ="Nettle, 2006"/>
In contrast, high levels of this trait have been associated with some severe psychological disorders, which indicates that extremely creative thinking can be damaging the the overall mental health of an individual. In these cases, the ability to attract a mate and the likelihood for reproductive success become significantly lower. <ref name ="Nettle, 2006"/>
Conscientiousness
Conscientiousness is one ability to think before acting, orderliness, and the ability to delay instant gratification for greater benefits later. It is generally seen as beneficial to have higher amounts of this trait for it promotes long term benefits and a safer livelihood.Yet those who are much higher than the optimum level are at a severe disadvantage when immediate opportunities arise, and often miss the benefits of these spontaneous opportunities. <ref name ="Nettle, 2006"/>
Extraversion
Extraversion is positively correlated with various mating advantages, including number and quality of sexual partners, thereby increasing an individual’s fitness. Not only is the trait beneficial for sexual reproduction, but it is also associated with higher sociability and social support. (Nettle, 2006) Studies have shown that variation in extraversion also predicts patterns of physical strength and attractiveness, and individual differences in this characteristic is most likely a result of prior reproductive strategies. <ref name ="Lukaszewski et al., 2011"/>
In contrast, there are limits to the benefits of extraversion due to risks involved in such behavior. An individual high in extraversion is more likely in their lifetime to be hospitalized, involved in criminal activities, and susceptible to divorce. <ref name ="Nettle, 2006"/>
Agreeableness
Agreeableness is a trait that is essential for socializing and relating to peers. Empathy and theory of mind are often associated with this quality, and high levels are seen beneficial to the fitness success of an individual (greater relations with one’s peers often leads to an advantage when attempting to find a mate). Agreeable individuals tend to avoid violence, resulting in an increase in their chances of survival.
Although it is true that a high level of agreeableness is can result in individual success, there are limits to the advantages of feeling trust and empathy towards others. To exhibit too much of each renders an individual prone to being taken advantage of, which can endanger their well-being, especially in potentially life threatening situations.<ref name ="Nettle, 2006"/>
Neuroticism
The negative effects of high neuroticism are fairly well known and include an increase in depression and/or anxiety as well as impaired health in general (due to the overworking of the body’s stress mechanisms). In regards to social livelihood, high amounts of neuroticism are often predictive of loner behavior and relationship failures.<ref name ="Nettle, 2006"/>
Although it is difficult to determine a functional reason for the normal distribution of neuroticism within the current population, it is hypothesized that in the ancestral environment, a level of neuroticism was critical for threat detection and avoidance of danger. Today, neuroticism is also linked to competitiveness and strive, therefore a certain amount within an individual holds the functional value of aiding in achievement within competitive situations.<ref name ="Nettle, 2006"/>
IV. Individual Differences and Personality
Evolutionary psychologists agree that personality differences evolved from psychological mechanisms that help guide human behavior in response to the various adaptive problems of our ancestors. These numerous mechanisms are species-typical and domain-specific to solve specific adaptive problems. <ref name = "Michalski & Shackelford, 2010"/> Humans evolved as a group of living species negotiating and competing for various resources and hierarchical status to further their fitness. <ref name = "Macdonald 1998"/> Those that responded with the necessary mechanism that would succeed in attaining those resources or status would survive. Therefore, for any trait to have importance it must have variability from its competitors. For example, extroverts are more open to the adventures of exploring new territory (allocating new resources) and are more social and friendly (which increases their reproductive success). However, they are much more likely than introverts to be exposed to dangerous pathogens from exploring unknown grounds or mingling with other people.
There is not just one evolutionary theoretical approach to explain why differing human psychological mechanism choose various personality traits. Some of the most common explanations include personality traits being due to life-history theory, costly signaling theory, fitness optima, frequency-dependent, and flexibility contingent shifts depending on environmental conditions.
Life-history theory describes personality and individual differences as a response to the different trade-offs different individuals make in respect to capturing and allocating energy. <ref name ="Buss 2009"/> Everything an individual does in life, whether it be growing or maintaining it’s own body, trying to reproduce, or rearing a child, cost valuable energy. Since energy is not limitless trade-off exists between the adaptive issues we encounter. In this sense, the energy spent searching new territory and food, cannot be spent on raising a child, it’s one or the other. This trade-off encompasses personality as well. Extroverts have an increased mating success and develop more social alliances, however, this trait comes with the trade-off of being exposed to high levels of risk. <ref name = "Michalski & Shackelford, 2010"/> The decisions humans make behaviorally and cognitively create a trade-off that established individual differences and various personalities.
Costly signaling theory is based on the face that individuals compete for resources and mating partners by sending signals about themselves. Only individuals in the best condition, physically, economically, with high energy can spare the energy it costs to send out these signals. <ref name ="Buss 2009"/> Character traits such as altruism, generosity, courage, and strength can only be expressed by those that can afford to use energy on it. So these expressions sends signals to other individuals informing them of their fitness.
Fitness optima bases individual differences in personality due to natural selection favoring different levels of personality traits in different environments. <ref name ="Buss 2009"/> It has been shown that geographical differences exist in accordance with the Big Five personality triats. For example, people in California, New York, and Florida are more open to experience. New York also houses a majority of neurotic people.
Frequency-dependent selection theory states that two or more strategies exist within a population at certain frequencies relative to one another, such that if one strategy is more prominent and common in the population it decreases your fitness. <ref name = "Michalski & Shackelford, 2010"/> In other words, natural selection chooses those strategies that are less popular, favoring the alternative strategy. An example of this is biological sex, as the male to female ratio increases, males fitness ultimately decreases. Research shows that personality differences are most prominent in social species, therefore it might be the social environment that provide various adaptive situations which require different personality strategies to succeed. <ref name ="Buss 2009"/>
The contingent shifts theory argues that personality traits are contingent upon or present in response to the environment of which it is exposed. <ref name = "Michalski & Shackelford, 2010"/> In other words our psychological mechanism are activated and operate in response to changes in environmental conditions. Contingent shifts can occur in response to conditions of life-history theory (as when a man shifts to a more conservative, less risky behavior after fathering a child), costly signaling theory (as when environmental conditions make sending signals less costly), during situation-specific conditions (becoming more aggressive and risky during times of famine when food is scarce), when an individuals social status changes, and even in response to heritable phenotypic qualities. <ref name ="Buss 2009"/>The main point here is that contingent shifts can occur in response to both the internal and external environment.
 
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