305 Lecture 4 Flashcards
describe the nature-nurture debate
- which matters more: inherited or acquired influences?
- nativist approach: nature
- empiricist approach: tabula rasa
- who should be blame: nature or parents?
describe the nature/nurture debate in regards to Steve Jobs
- Steve Jobs was adopted, but his biological parents were highly intellectual
- his biological sister is an award-winning author –> both are driven, conscientious, creative, etc.
- seems like nature might play an important role
describe the level at which the nature/nurture debate takes place
- on the group level, not the individual level
- inseparable intertwining of genes and environment –> genes are expressed in an environment, so can’t ask which is more important
- we can only debate the degree of influence on specific behaviours/traits
describe the study on the 10,000 hour rule
- one study found average practice time for elite violinists was 10,000 hours –> characteristics reflecting “innate talent” is actually just the result of intense practice
- BUT there is evidence that not everyone can be accomplished in every field, and there is inconsistency in deliberate practice among experts
- evidence that genes account for over 50% of variance in talents and abilities
what is heritability
- proportion of observed variance in group of individuals that can be explained or accounted for by genetic variance
- applied only to groups (not individuals)
- not constant/absolute –> varies between populations
- not a precise statistic –> errors in measurement
what is environmentality
- proportion of observed variance in group of individuals attributable to environmental variance
- greater environmentality = lesser heritability
what are the two assumptions of twin studies
- equal environments
- representativeness
what do adoption studies show
correlations between adopted children and genetic parents = genetic influence
what are the strengths and limitations of adoption studies
- strength: genetic parents are providing no environmental influence (no confound)
- limitation: potential for selective placement of adopted children (select children because they look similar to them, might share some genes)
what study design is strongest in determining heritability
monozygotic twins reared apart
based on studies of MZ twins reared apart, what are the heritability estimates of personality
- heritability estimates for many traits are >50% in correlational analyses, closer to 40% using linear modelling
- neuroticism has a high heritability estimate based on correlational analyses, but less so in more advanced linear modelling formulas
what did a meta analysis on the heritability of the big 5 traits suggest
- twin studies have an average heritability estimate of .48 for big 5 traits, .44 for Eysenck’s model
- heritability across all traits is estimated as 49%
what are some examples of shared vs non-shared environmental influences
- shared: parental beliefs/attitudes, neighbourhood, number of books in house
- non-shared: birth-order, changes in parenting style, unique experiences
when looking at the effects of genetics, shared environment and non-shared environment on personality, what is observed
- genetics and non-shared environment account for about 50% of variance each
- shared environment has little influence on personality
what are some observed impacts on non-shared envrionment on siblings
- youngest child is more likely to be gay in male siblings –> might be adaptive (less competition for mates)
- intelligence decreases with each subsequent child –> less resources put into each child?
what aspects of a person are influenced by shared environment
- attitudes
- religious beliefs
- political orientation
- health behaviours (smoking, drinking)
describe genotype-environment interaction
- the environment has a different impact depending on genotype
- e.g. abused children with genotype that produces less MAOA are more likely to develop antisocial personalities
- e.g. Steve Jobs’s gnees predisposed him to low neuroticism so after being fired he started another business instead of just giving up
describe genotype-environment correlations
exposure to environmental conditions depends on the genotype –> can be passive, reactive or active
what are epigenetics
the study of changes in organisms caused by changes in gene expression due to environmental influences –> how nurture shapes nature (are genes expressed or silenced?)
what have epigenetics been shown to have an impact on
- risk-taking behaviour
- anxiety and stress reactivity
- sociability
- people actively trying to display more kindness have epigenetic changes associated with greater resilience
what are the two genes that have been found to have direct links to personality
- dopamine receptor gene (DRD4) –> novelty-seeking and extraversion, psychiatric conditions
- serotonin transporter gene (5_HTTLPR) –> neuroticism, depressive/anxiety-related traits
how many genes are involved in traits
- many –> e.g. GWAS have found 9 neuroticism-associated loci
- only dopamine receptor and serotonin transporter genes seem to have direct links to personality
- almost everything is partially heritable
how come most traits/behaviours are at least partially heritable
- genes affect NTs, hormones and physiological arousal
- these things can affect thoughts, feelings and behaviours over time, which form traits
- traits influence our behaviours (e.g. relationship behavious, which can lead to divorce)
what are the three main biological mechanisms of personality
- individual differences in brain structure, function and connectivity (e.g. amygdala associated with neuroticism)
- individual differences in optimal level of arousal (e.g. associates with extraversion)
- individual differences in NT levels/regulation (e.g. serotonin levels associated with harm avoidance)
describe some individual differences in NT levels/regulation
- serotonin levels associated with harm avoidance
- norepinephrine levels associated with reward dependence
- dopamine levels associated with novelty-seeking
what part of the definition of personality doesn’t apply to nonhuman species
“adaptations to the intrapsychic environment” –> how do we examine intrapsychic concepts like self-concept and self-esteem in nonhuman species
describe the study on fish that showed evidence of personality
- strategies of honesty and cheating differ in cleaner fish
- individual exhibiting greater feeding effort and less exploration = less cheating
- bolder and active = cheating
what were the 5 personality traits found in Chimps
- reactivity/undependability
- dominance
- openness
- extraversion
- agreeableness
–> suggests we share at least 60% of our personality traits with chips, suggesting an evolutionary basis to personality (must play a functional role)
what is evolutionary continuity
- all animal capacities and behaviours exist (to various degrees) in continuity with other species
- there is no empirical justification for human exceptionalism
- everything psychological in humans is in some way present in other species
what is argued by evolutionary psychology
- all humans today come from an unbroken line of ancestors who have survived and reproduced
- we carry the adaptive mechanisms that led to our anestors’ success
- human nature and personality are made of a collection of evolved traits and mechanisms
what have been the two components to our evolutionary success as a species
- getting ahead (agency) and getting along (communion)
- communities with more sympathetic members flourish best and rear most offspring
- need to engage with others AND pursue personal goals/distinctiveness, in that order –> without communion, we have no need for agency
according to evolutionary psychology, what is instinctive to us
- communion/cooperation, NOT competition/agency
- e.g. Tomasello’s helping tasks, showing that it is instinctive to help without any reinforcement (and helping actually declines when there is reinforcement)
from an evolutionary perspective, what are the two levels of analysis that need to be considered
- human nature (what are all people like)
- individual/group differences (how/why are people different from one another)
describe the human nature perspective in evolutionary psychology
- human nature is a product of evolutionary processes
- over time, more successful psychological mechanisms and traits spread through the population –> eventually characterize all humans
- e.g. helping/altruism, empathy
describe why the need to belong is functional
- we are safer in large numbers, have more resources and have more potential mates
- we experience social anxiety because of this need to belong (except in schizoid PD)
- Bonobo monkeys are our second closest relative and they are very affectionate, and don’t have inter-group conflict
describe why empathy is functional
- social cohesion and cooperation
- taking perspectives increases chances of giving/receiving help
- Rhesus monkeys will avoid eating to prevent another monkey from receiving a shock
why is helping/altruism functional
- direct function of recipient’s ability to enhance the inclusive fitness of the helpers
- people are more likely to help others who are more closely related to them in survival situations (e.g. siblings)
describe the universality of emotions
- emotions and expressions must have an evolutionary basis is they are shared by all members of a species (e.g. monkeys and humans both react to cold stethoscope)
- they are an adaptive psychosocial mechanism –> signal pain, pleasure, etc. to others
- emotions can be used to manipulate others
what are some “less desirable” traits that we all share that might still serve an adaptive function
- jealousy, envy, narcissism, selfishness
- these might result from evolutionary pressures to survive
- tribal narcissism (in-group/out-group biases) might be a means of protecting those close to us
describe the evolutionary basis of humans’ propensity for aggression and war
- humans and chimps are the only primates who engage in lethal aggression/warfare
- chimps have a lower expression of the ADRA2C gene (which inhibits fight or flight responses)
- fight/flight less inhibited = better equipped to run into battle –> might have developed more recently as a result of intergroup aggression
what is the naturalistic fallacy
- tendency to believe that what is natural is what is “good/right/moral”
- e.g. lobsters naturally develop dominance hierarchies, so hierarchies in human society must also be natural and thus right?
what are the four leading explanations for the maintenance of individual differences over time
- environmental triggers of differences
- frequency-dependent selection of traits
- contingencies among traits
- optimal variance over time and space
describe the environmental triggers of differences
- individual differences result from environmental differences acting on species-typical psychological mechanisms
- transgenerational epigenetic mechanisms have maintained these traits over time
- e.g. individual differences in neuroticism may result from differences in stressors/demands in early life environments (e.g. childhood adversity leading to more aggression in adulthood)
describe the “contingencies among traits” explanation for individual differences in traits
- individual differences result from contingencies among traits
- other traits (e.g. physical) may make the expression of certain psychological traits more/less adaptive
- e.g. quick temper is more advantageous if you are big and strong, not if you are weak
describe the “frequency-dependent selection” explanation for individual differences in traits
- reproductive success of a trait depends on its frequency relative to other traits in a population –> as a trait becomes more common it may become less successful because of a loss of competitive advantage or social response
- e.g. selection might favour cheaters in a cooperative population, but when cheating becomes too frequent (and people become more aware of it happening), then it’s too hard to cheat (frequency declines)
- e.g. psychopathy in population is low so it goes more unnoticed
describe the “optimal variance over time and space” explanation for individual differences in traits
- different levels of a trait are optimally adaptive in different environmental conditions over time –> creates heritable differences in personality that are maintained
- “balanced selection” to maintain diversity
- e.g. during food scarcity selection favours risk taking, but during food security selection favours caution –> both traits become common in population over time
- e.g. during pandemic selection favours low openness, during low disease risk selection favours high openness
describe balancing selection in regards to the big 5 traits
- no unconditionally optimal value of the big 5 traits, thus we should expect genetic diversity to be maintained
- we should be able to identify both the benefits and the costs associated with the big 5 traits (e.g. neuroticism = increased vigilance to danger AND increased stress responses)
describe balancing selection in regards to extraversion
- benefits: mating success, social allies, exploration
- costs: physical risks, family stability
describe balancing selection in regards to the 7R allele and novelty-seeking
- 7R allele of the DRD4 gene occurs at different rates in different geographical regions
- favoured by evolutionary selection when people migrate to new environments or inhabit resource-rich environments (beneficial in migratory/nomadic populations, not sedentary populations)
- could be caused by selective migration of individuals with those genes –> selectively favours genes in new environments, or both
- DRD4 gene is a risk factor for ADHD
describe why personality differences are most pronounced in social species (e.g. humans)
might be the social environment that provides an array of different adaptive niches in which different personality strategies can succeed –> we have developed the capacity to detect these traits in others
describe our difference-detecting mechanisms
- we have developed the ability to notice/remember individual differences that have relevance for solving adaptive problems
- e.g. who is likely to risk in the hierarchy –> extraversion, dominance
- e.g. who is likely to be a good cooperator –> highly agreeable
