Lecture 8 Flashcards
Why are inter-individual differences a problem for evolutionary psychologists?
Because selection pressures should eliminate all the those that have fitness advantages, meaning we should only see personality types that have the highest fitness. This is the problem of polymorphism as individuals are present, thus going against the principle of fitness.
Discuss Tooby and Cosmides’ false view about why individual differences exist
They argued that there are two reasons why individual differences exist; polymorphs are either so irrelevant that they are just ‘noise’; non-adaptive random fluctuations, or they are so extreme that they push evolution among the species/population to new uniformity.
What are the three explanations for inter-individual differences?
Strategic specialisation, life-history strategies and frequency dependent selection.
Discuss strategic specialisation
This is also known as niche picking. Personality reflects different strategies of fitness in order to reduce competition. This is shown with birth order; the first born identify with parents and last born are more rebellious. You can also see this with different specialisations among the beaks of Darwin’s finches. At some point your personality characteristics will be favourable; when there is limited food, bold birds will have an advantage as they’re more likely to explore to new areas and fight off competition but when there is an abundance of food, less bold birds have an advantage as they don’t start fights, which could compromise their fitness, for no reason whereas the bold birds do.
The big 5 personality traits can all relate to fitness; introversion can result in more parenting effect and less physical risk whereas extroversion results in more mating success. Openness can result in one being more creative with obtaining food/mates and cautiousness can result in decreased risk of being predated.
Discuss life history strategies
Life history strategies are strategies to improve fitness developed from an individual’s conditioned response to the environment. For example, father presence or absence during upbringing affects women’s reproductive strategies; father absence means women focus more on mating as they become more opportunistic due to the belief that men have a roaming style whereas father presence results in a focus on rearing as they have had a history of monogamy. Father absence also results in earlier mating.
In terms of men, father absence results in earlier voice breaking and reproduction, perhaps because they have grown up with a father using the roaming strategy so they therefore developing the strategy to copulate with as many females as early as possible.
Discuss frequency dependent selection
This is the idea that the success of one’s individual difference could depend on how many others in the population have this trait. For example, Blue gilled sunfish. There are traditional large males who have successful mating but there are also less common males that mimic females. This means that they can copulate without the large dominant males noticing. If there were too many using this strategy then it wouldn’t work as the large males would develop strategies to detect the mimics so it’s dependent on the frequency of this trait.
Another example is psychopathology; although there’s no fitness advantages in terms of reproduction, there are advantages in personal survival. Psychopathic people are more able to feign cooperation and are very good at social charm. They can go undetected because of this, however, if there were significantly more psychopaths then we would evolve mechanisms to detect them.
Discuss intra-individual variation
Personality isn’t always stable, it constantly changes throughout one’s life. One example of this is ovulation. Other mammals are obvious about their ovulation like big pink bums in monkeys. However, humans conceal their ovulation. Despite the concealment, there are still behavioural differences during ovulation; women’s sexual desire peaks here and they prefer masculine faces. When not ovulating, they prefer feminine faces as these are more likely to focus on rearing. Also during ovulation, women prefer men with talent rather than with resources and opposite during the rest of the month. Finally, during ovulation lap dancers gain more tips, perhaps because they dance more provocatively. It is important to note that all these difference in behaviour are unconscious.
Discuss Johnstone’s study
Although it’s stated in the lecture that the big 5 personality types are present due to strategic specialisation. Johnstone claims that individual differences in leadership is due to frequency dependent selection. Followers are more common in the population and get by by being cooperative. However, leaders have an advantage as they get to impose their preferences on their followers meaning things act in their favour. This is frequency dependent because leaders are unable to coordinate effectively with other leaders so if there are many leaders, then they will not have any advantage.
Discuss Hertler’s study
They explored the continuum of conscientiousness and explained how each end of the spectrum is strategically specialised. Each extreme end of conscientiousness correlates with a behavioural disorder; the conscientious end is OCD (rigidity, compulsiveness, orderliness) and the other end is antisocial PD (impulsive and illicit). The evolutionary benefits of APD is claimed to be a skill in exploiting exchanges within a large population. OCD evolved due to our seasonal climate; when humans left Africa, they had to adapt to a seasonal climate. This is where OCD had an advantage because it means they always had a feeling of urgency, compulsiveness and future oriented attention.
Discuss Jonason’s study
They explored evolutionary origins behind the dark triad; narcissism, psychopathy and machiavellianism. All three of these traits involve the exploitation of resources/people. These three traits are examples of strategic specialisation as they are advantageous due the attainment of their goals via exploitation. The only reason that these three traits separated from one another is because different evolutionary paths guided their exploitative nature, resulting in different emotional deficits. N= Selfish, M= deception, P= Impaired empathy.
Discuss Nettle’s study
They argue that adverse experiences in early life accelerates reproductive timing. This is because of life history theory. These early life experiences have a negative impact on one’s health causing the body to fail more rapidly as they get older. Therefore, as an evolutionary mechanism, these people adjust their reproductive timing to account for this rapid decline.
Discuss Dingemanse’s study
They explored within individual variation of great tits and explained that habituation is an example of this. When the birds were presented into a novel environment, they didn’t explore it much but repeated exposure to this environment allowed behavioural plasticity to occur causing the birds to be more bold (changes in personality) and explore more. This idea of habituation can be applied to humans, for example having an innate fear of snakes (due to evolution) can be diminished via repeated exposure, thus showing within individual variation of having the innate fear to no longer having it, going against our evolutionary mechanisms.
