Chapter 1
Personality: the set of psychological traits and mechanisms within the individual that are organized and enduring that influence the individuals interactions with environment
Psychological traits: characteristics that describe ways in which people are different or similar from each other
Traits describe the average tendances of a person eg on average talkative person starts more conversations than non talkative
Research on personality traits asks four main questions: how many traits are there, how are the traits organized, what are the origins of traits and what are the correlates and consequences of traits
Why are traits useful? →
Help us describe people and help understand dimensions within people
Help explain behaviour
Help us predict future behaviour
Psychological mechanisms: the processes of personality eg someone who is extraverted may look for opportunities to interact with others
Psychological mechanisms have 3 ingredients: inputs, decision rules, and outputs
Input: psychological mechanism may make people more sensitive to certain kinds of information from environment →
Decision rules: may make them more likely to think about specific options →
Outputs: guide their behavuour toward certain categories of action
Not all traits and psych mechanisms are activated at all times, only a few activated at a given time →
Eg the trait of corageousness is only activated when people are in dangerous/life threatening situations (very relevant to you)
Within the individual: personality is something a person carries with themselves over time and from one situation to the next, it is enduring
Organized: psychological traits and mechanisms for a given person are not simply a random collection of events→ personality is organized because traits and mechanisms are linked to one another
Psychological traits enduring over time
May be situations where generalization of traits does not hold eg some situations are overpowering and suppress the expression of psychological traits eg talkative people might stay quiet during lecture
Some psychologists eg mischel argued that evidence for consistency in personality is weak → eg honesty in one situation may not transfer to honesty in another
Most psychologists argue that people are not perfectly consistent, there is enough consistency
Influential forces of personality: personality traits can have an effect on peoples lives
2 people may be exposed to the same event but how the perceive it may be different, and this difference is said to be a function of their personalities
Selection: the manner in which we choose situations to enter eg how we choose our friends
Evocations: the reactions we produce in others, often unintentionally, eg a hyperactive child may evoke parents to attempt to constrain child
Manipulations: the ways in which we intentionally attempt to influence others eg someone who is anxious may try to convince their friends to stay in instead of go clubbing
Adaptations: central feature of personality is adaptive functioning eg adjusting to deal with challenges → some features of personality represent deficits in normal adaptations eg breakdowns in how to cope with stress
Environment: our fears help us avoid danger
The ways in which we cope with our social environment, our struggle for love belongingness and esteem are central to our understanding of personality
3 levels of personality analysis
Human nature: traits mechanisms of personality that are typical for our species → spoken language, the desire to live with others and belong to social groups
Individual and group differences: ways in which each person is like some other people eg extraverts, sensation seekers –. Differences among groups; one group may have certain personality features that make group different from other group →
Important differences between male and females: eg males are more aggressive than females, males are responsible for most of the violence in the world
Individual uniqueness: no two individuals are the same
Nomothectic research: involves statistical comparisons of individuals or groups
Indiographic research: research focuses on one single subject
Research in personality
Eastern cultures tend to be more collectivist and western cultures are more individualistic
Field of personality have been critisized for having too many independent areas of investigation
Each perspective on personality captures an element of truth but is inadequate to describe entire realm of human personality
6 domains of knowledge about human nature
The whole personality is a sum of its parts
Dispositional domain: deals with ways individuals differ from each other, people can differ in their 5 habitual emotions, their habitual concept of self, physiological propensities and intrapsycic mechanisms.
Biological domain: core assumption is humans are collections of biological systems and these systems provide building blocks for behaviour thought and emotion → first area of research is genetic underpinnings of personality eg twin studies→ second is psychophysiology where researchers summarize personality as nervous system functioning eg cardiac reactivity → third approach is how evolution shapes personality
Intrapsychic domain: mental mechanisms of personality, many of which outside of consciouss awareness→ theory begins with assumptions of instinctual system, that sexual and agressive forces dictate much of human activity → includes subdomains of; repression, denial, and projection, closely linked to freud
Cognitive experientiall domain: cognition and subjective experiences eg consciousness, thoughts, feelings, beliefs and desires→ emphasis on self concept eg morals, esteem → emphasis on emotions
Social and cultural domain: personality is not something just in our heads, nervous system our genes, but is affected by social and cultural context → different culture many bring out different faucets of our personality→ eg everyone may have the capacity to be peacefu or violent, which one of these capabilities is displayed depends on the culture we are part of
Adjustment domain: personality plays key role in how we adjust adapt and cope → eg personality is linked to heart disease, because people more likely to cope maladaptively are at greater health risk
Role of personality theory
A good theory: provides a guide of researchers, organizes known findings, and makes predictions
Beliefs differ from theories because they are based on faith, not reliable facts and systemic observations
5 scientific standards for evaluating personality theories→ comprehensive, heuristic value, testability, parismony, compatibility and integration across domains and levels
Comprehensiveness: does the theory do a good job of explaining all facts and observations within its domain
Heuristic value: does theory provide a guide to important new discoveries about personality that were not previously known
Testability: does theory provide precise predictions that can be tested empirically eg frueds theory are critized for lack of testability
Parsimony: does the theory contain few premises and assumptions (parsimony) or many premises and assumptions (lack of parsimony)--> parsimony is important but does not mean simple theories are always better than complex ones → it is our view that personality is complicated therefore we may need a complicated theory
Compatibility and integration across domains and levels: a personality theory in one domain that violated another domain would be problematic
Personality field lacks one unifying theory
An ultimate theory of personality would have to unify all 6 domains
Chapter 2
unstructured :open ended
Structured: eg tell me about parties you like
20 statements test: 20 “i am” questions
Simplest form of self report questionnaire involves series of trait descriptive adjectives eg active, anxious, open minded, manipulative
Likert type scale: requires participants indicate numerical form the degree to which they identify with a trait
Personality scale: involves summing the scores on a series of individual rating scales
Self report questionnaire limitations: participants may not answer honestly, lack of self knowledge
Observer report data: capitalize on external sournces like friends families or teachers to get information about a persons personality →
Advantage observers may have info others do not, multiple observers can be used
Some psychologists use professionally trained personality assessors who do not know subject
Second strategy use to use people who know subject; these people are in better position to observe participant in natural environment
Henry murrays bridge building test: person being assessed is given two assistants and a collection of wood, rope and tools and they then have the task of buildin a bridge over a small creek, the person being tested cannot work alone, the 2 assistants are role players, one playing a know it all and one is clueless and stupid → the subject is being evaluated on tolerance of frustration and performance under adversity
Actometer: mechanical recording device to assess personality difference in activity or energy level
Eye blink startle response used to test anxiety levels of suspected psychopaths as psychopaths are thought to lack anxiety
fMRI: used to identify areas of the brain that light up when performing certain tasks → works by guaging the amounts of oxygen brought to particular part of the brain
Projective techniques: person given a standard stimulus and asked what they see, how they interpret it→ eg inkblot test
Life outcome data: refers to information that can be gleaned from the events, activities and outcomes in a persons life that are available to public scrutiny eg marriages and divorce
O data: obersvations
L data: life outcomes
For men early temper tantrums linked to negative outcomes in adult life eg eratic work lives, divorce
Self report data
Obtained by interviews, surveys questionaires
Self report can range from fill in the blank to forced choice true or false
Structured questionaires are more common than open ended questions
triangulation : if same results are found with two or more data sources, greater confidence in credibiliity
Evaluation of personality measures
reliability : the degree to which an obtained measure represents the true level of the trait being measured, results are consistent over time →
Way to estimate reliability: repeated measurement →
Internal consistency reliability: reliability is assessed within the test itself
Inter rater reliability: to obtain measurements from multiple observers → applicable only to use of observer based personality measures, when raters fail to agree the measure has low inter rater reliability
Response sets: the tendency of some people to respond to questions on a basis that is unrelated to the question content eg the tendency to simply agree with items regardless of content
Extreme responding: tendency to answer strongly agree or strongly disagree to avoid the middle part of response scales eg slightly disagree
Social desirability: tendency to answer questions in a way that comes across as socially desirable
Two interpretation of social desirability→
One view is that it represents distortion and should be minimised or eliminated →
Other view is that social desirability is valid part of other desirable personality traits eg happiness conscientiousness
Social desirability is not always conscious or intentional→ so subjects are not lying per say
Social desirability can be scored when questions specifically ask participants about normal/common human faults and they answer no this suggests saint like behaviour and they will get a high score on social desirability
Forced choice format: test takes confronted with pairs of statements and are asked to indicate which statement in each pair is more true of them → these statements are similar in social desirability forcing participants to choose between statements that are equal in social desirability
Some psychologists view social desirability as a distortion to be eliminated some view it as an important trait →
They consider social desirability to be a trait in itself that is correlated with positive traits eg happiness, adjustment, conscientiousness→
Research finds that unrealistic positive views about self are related to better physical health
Validity: the extent to which a test measures what it claims to measure
Face validity: whether the test on the surface appears to measure what it is supposed to measure eg a test measuring manipulation would need to have questions like “ i made a friend just to obtain a favour”
Predictive validity: whether test products criteria external to the test eg a scale measuring sensation seeking should predict which people actually take risks to obtain thrills
Convergent validity: whether a test correlates with other measures that it should correlate with eg if self report measure of tolerance corresponds well to peer judgements of tolerance
Discriminant validity: what measure should not correlate with, part of knowing what a measure measures is knowing what it does not
Construct validity: test that measures what it claims to measure, correlates with what it is supposed to correlate with and does not correlate with what it is not supposed to → broadest type of validity → personality variables are theoretical constructs eg showing your intelligence is a hard thing to do/ measure
Generalizability: degree to which the measure retains its validity across various contexts
Research designs
Experimental methods: used to determine causality, find out whether one variable influences another variable, control and experimental group
Difference must be large enough to be statistically significant
A difference that is significant at the 0.05 level means that the finding would only occur by change alone 5/100 times
Correlational method: procedure used for determining whether there is a correlation between two variables
Correlation coefficient: can range from +1.00, 0.00 to -1.00
Variables of interest positively related to each other: +0.01 to +1.00 →
Unrelated to eachother: 0.00 →
Negatively related to each other: -0.01 to -1.00
Psychologists reqienre a probability of 0.05 or less before referring to correlation as significant
2 reasons why correlation cannot prove causality →
Directionality problem: if A and B are correlated, we do not know if A is the cause of B or if B is the cause of A→
Third variable problem: 2 variables might be correlated because of a third unknown variable
Case study method can be used to formulate a general theory to be tested on a larger population
Chapter 3
Traits and trait taxonomies
Five fundamental personality traits: extraversion, neuroticism, agreeableness, conscientioussness and openness to experience
Act frequency approach: starts with notion that traits are categories of acts eg trait categories such as impulsivity have specific acts as members
In act frequency formulation, a trait is a descriptive summary of general trend in a person's behaviour
Act nomination: procedure designed to identity which acts belong in which trait categories, researchers can then identify hundreds of acts belonging to various trait categories
Prototypically judgement: identifying which acts are most central to or prototypical of each trait category eg when you think of birds which birds come to your mind first
Recording of act performance: securing information on the actual performance of individuals in their daily lives
Criticisms to act frequency formulation: does not specify how much context should be included in description of trait relevant act, only applicable to overt actions but doesnt account for failures to act or covert acts that are not directly observable
Identification of most important traits
3 approaches used to identify important traits →
Lexical approach: all traits listed and defined in the dictionary form the basis of describing differences among people
Lexical hypothesis: all important individual differences have become encoded within the natural language→ people have invented words to describe their differences
Lexical approach has 2 major criteria→
Synonym frequency: if an attribute has not merely one or two trait adjectives but rather many other words then it is a more important dimension of individual difference → the more important an attribute the more words can be used to describe it →
Cross cultural universality: the more important important a trait is the more languages will have a word for it
Statistical approach: uses factor analysis to identify major personality traits →
Factor analysis: identifies groups of items that go together but tend not to go together with other groups of items, identifies cluster of personality items that tend to go together (covary)
Theoretical approach: researchers rely on theories to identify important traits → identifying important dimensions of individual differences starts with a theory that determines which variables are important
Taxonomies (classification) of personality
Eysencks hierarchical model of personality
strongly rooted in biology, he was outspoken about the heritiability of intelligence which was highly contraversial→
Argued that racial differences in IQ were not due to social factors but rather genetic differences between races (yikes) obviously proved to be inaccurate
Developed model of personality traits he believed to be heritable: extraversion- introversion, neuroticism-emotional stability and psychotisism
Neurotisism
Neurotosism: cluster of traits including, anxious, irritable, lacking self esteem, tense, shy, irritable, →
high N scorer more likely depressed and has sleeping issues and experience greater degree of emotional arousal
Trouble returing to baseline after being angry
Less likely to forgive
Psychoticism
Constellation of traits including; aggressiveness, egocentric, creative, impulsive, lacking empathy, creative, impulsive and antisocial (meaning socially disruptive)
Categorised by p scale
Biological
All three traits, P, E and N have proven to have biological underpinnings/moderate heritability →
But so do many personality traits
Wiggins interpersonal circumplex
Wiggins started with lexical assumption- the idea that all important individual differences are encoded within the natural language
Wiggins concerned mostly interpersonal traits→
Interpersonal traits: what people do to and with each other
He defined interpersonal as: interactions among people involving exchanges →
The 2 resources that define social exchange are love and status →
Interpersonal events have 2 consequences social status or emotional love →
Primary human motives →
Agency: motive to get ahead →
Comunion: motive to get along →
These also include denying love and denying status
3 types of relationships between traits specified in model →
Adjacency: how close the traits are to each other →
Bipolarity: traits that are bipolar are located opposite sides of the circle and are negatively correlated →
Orthogonality: traits that are perpendicular to each other on the model, at right angles of eachother are unrelated
Five factor model (big five)
Originally developed based on combination of lexical and statistical approaches
Extraversion: talkative, assertive, forward, outspoken →
versus quiet, shy, introverted, bashful, inhibited
Agreeableness: sympathetic, kind, warm, understanding sincere→
versus unsympathetic, cruel, harsh
Conscientiousness:organized, neat, orderly, practical, prompt, meticulous →
Versus disorganised, disorderly, careless, sloppy
Emotional stability (low neuroticism): calm, relaxed, stable →
Neuroticism; moody, anxious, insecure, angry, hostile, self conscious, impulsive
Openness to experience: intellect or imagination, creative, imaginative, intellectual →
Versus uncreative, unimaginative, unintellectual
Contributions of big five variables
Conscientiousness: predicts good grades and emotional stability
Low conscientiousness: predicts academic dishonesty
High extraversion and neuroticism: predicts risky sexual behaviours
High extraversion and low conscientioussness: predicts increased alcohol consumption
High neuroticism and low conscientiousness: linked to drug abuse
High neuroticism and low extroversion: linked to eating disorders
High neuroticism and low conscientiousness: linked to gambling
High emotional stability and high agreeableness: more likely to forgive
High conscientiousness, high extraversion and high agreeableness: linked to leadership in business environment
Chapter 4
Theoretical measurement issues in trait psychology
ionTrait theories share 3 important assumptions about personality → assumptions are
Meaningful individual differences, stability and consistency over time, consistency across situations
Meaningful differences between individuals: Trait psychologists interested in ways people differ from each other→
Because of this trait psychology has also been called differential psychology
Differential psychology;includes study of other forms of individual differences in addition to personality traits
Trait psychologist somewhat like chemists, they argue that by combining a few primary traits in various amounts they can distill unique qualities
Consistency over time: there is a degree of consistency in personality over time →
Note that although traits can be consistent over time but the way in which they manifest themselves in actual behaviour can change
Rank order: if all people show a decrease in particular trait at the same rate over time they might still maintain the same rank order relative to each other eg those who were most impulsive earlier in life might have decreased impulsivity as they get older but they are still the ones who are most impulsive
Consistency across situations: traits will exhibit some consistency across situations →
this has been debated because of limitations eg someone is more likely to start conversations at a party than at the library
Mischel concluded: behavioural consistancies have not been demonstrated and that psychologists should use →
Situationism: explain behaviour in terms of situations and not personality traits
Person situation interaction: behaviour is a function of an interaction between personality traits and situational forces eg if a situation is frustrating and if the person has a bad temper, then aggression will likely be the result
Situational specificity: when a person acts a certain way under particular circumstances
Some trait situation interactions are rare eg courageouness
Strong situation: a situation in which nearly all people react in similar ways eg death of a loved one →
By contrast, when situations are weak/ambiguous personality has greater influence
How we interpret social situations may reveal our personalities
Situational selection: the tendency to choose the situation one finds themselves in → people do not typically find themselves in random situations →
The situation they select may reveal parts of their personality→
We can investigate personality by the choices people make in life, people typically pick situations that match their personality
However once in a situation, the situation can affect one's personality
Person environment fit: there are particular environments or situations that are more complementary to a persons traits that may motivaye individuals to select certain situations over others → people tend to feel happier when they choose environments that suit their personality
Evocation: idea that certain personality traits may evoke specific responses from the environment eg people who are manipulative may evoke certain reactions in others like avoidance or hostility
Manipulation: means by which people influence behaviour of others
Types of manipulation: charming, silent treatment, coersion
Aggregation: the process of adding up or averaging several single observations resulting in better measure of personality
Measurement issues
Trait approach relies on self report questionnaires to measure personality
Some people unwilling to disclose information or may be motivated to distort or falsify self reports
Carelessness: some participants filling out trait questionnaires might not be motivated to answer carefully or truthfully, rush through questionnaires
Infrequency scale: contains items that all people will answer in a particular way, so if a person answers these wrong the test is flagged as suspicious
Faking: purposely distorting results for either perception of self or how that person is perceived to others eg workplace personality tests
To detect fakers, researchers asked participants to fake good and fake bad and take data from these to create a faking bad profile and a faking good profile
False negative: when psychologists conclude that a truthful person was faking
False positive: when psychologists conclude that a person who was faking was telling the truth
Barnum statements are generablities, statements that could apply to anyone, though they often appear to resonate with the reader eg astrology
Personality and predication
Personnel selection: employers use personality tests to select people who are suitable for a certain job
Integrity testing: personality tests that assess honesty or integrity → designed to predict a tendency toward theft or other negative behaviours in the workplace →
Measure attitudes/constructs of: tolerating others who steal, rationalizations that theft may be acceptable, intertheif loyalty, antisocial beliefs and behaviourd →
Tests concluded to be reliable with test retest correlations of 0.85
Concerns over negligent hiring: hiring an applicant with traits that posed a threat of injury to others
to avoid negligent hiring; eg should a employee assault a constumer on the job the employer could be held legally accountable and charged with negligent hiring
Legal issues in work personality test usage]
Right to privacy: given fact that employees are unaware of the implications of their responses, they are more likely to reveal private thoughts and feelings → conclusions may be drawn about intelligence or mental health, which people like to keep private →
Right to privacy being violated is an act subject to liability in canada
Discrimination: individuals may be discriminated against based on their personalities or mental health → if any traits are associated with minority groups eg lgbtq women, the tests may be used to discriminate on that basis
Employment equity act: requires that federally regulated industries in canada adopt proactive employment rates of four designated groups; women, disabled people, and first nations → part of this act is the necessary removal or barrier for these groups eg inaccessible wheelchair buildings must be changed
Canadian human rights act: includes the following as prohibited grounds of discrimination: race, national or ethnic origin, colour, religion, age, sex, sexual orientation, marital status, family status, disability and conviction for which pardon has been granted
Disparate impact: to prove case of disparate impact a plaintiff must show that an employment practice disadvantages people from a protected group → most courts define disparity as a difference that is sufficiently unlikely to have occurred by chance
Race or gender norming: eg it is illegal for companies to set a higher threshold for women than men on their selection test
Chapter 5
Personality development; can be defined as the continuities in people over time and the ways in which people change over time
Rank order stability: the maintenance of individual position within a group, if people tend to maintain their positions of eg dominance and extroversion relative to others over time, then there is high rank order stability
Rank order change: if people fail to maintain their rank order eg if submissive people turn dominant
Low reteast correlations would suggest rank order change
Mean level stability: the degree to which personality stays constant eg the degree to which a conservative maintains their conservative values→ if views do stay the same then this is a high mean level stability
Mean level change: eg conservative becoming liberal
Personality coherence: changes in the manifestations of the trait eg a dominant child may display this in rough housing, whereas an adult may display dominance as debating someone on political views → therefore personality coherence involves stability and change
Personality coherence: maintaing rank order in relation to other individuals but changing the manifestations of the trait
Personality change/development: changes are internal to the person not merely changes in external surroundings, the changes are also enduring over time
Three levels of analysis
Population level: deals with the changes and constancies that apply more or less to everyone eg change in impulsivity from 16 to 30
Group differences level: some changes over time affect different groups of people differently eg girls go through puberty earlier than boys, men also due earlier than women → sex differences can occur in realm of personality too →
Men and women develop differnently in terms of empathy, women develop stronger empathy
Other group differences include cultural or ethnic group differences eg european candian children are at higher risk of developing externalising disorders such as ADHD whereas asian canadian children are more likely to develop internalizing disorders like anxiety and depression
Individual differneces level: focus on individual differences in personality development eg can we predict through their personalities who will go through a mid life crisis
Personality stability over time
Temperament: individual differences that emerge very early in life and are likely to have a heritable basis, often involved with emotionality or arousability
6 factors of temperament (mary rothbart) →
Activity level: infants overall motor activity including arm and leg movements
Smiling and laughing” how much the infant smiles or laughs
Fear: the infants distress and reluctance to approach novel stimuli
Distress to limitations: the childs distress at benign refused food, being dressed, being confined, or being prevented access from a desired object
Soothability: the degree to which the child reduces stress or calms down as a result of being soothed
Duration of orienting: the degree to which the child sustains attention to objects in the absence of sudden changes
Stability during childhood: examined by longitudinal studies
Stability coefficients: the correlations between the same measures obtained at 2 different points in time
Validity coefficients: correlations between different measures of the same trait obtained at the same time
Actometer: recordin device attached to the wrists of children during several play periods
Actometer study concluded correlations of activity level measurements are positively correlated with measurements of activity level later in life, demonstrating stability
Rank order stability in adulthood: determined in longitudinal studies when big five remain consistent over time → studies confirm that rank order personality stays stable in adult life
Mean level stability in adulthood: despite stability there are still slight changes eg there is a tendency for extraversions, openness and neuroticism to gradually decline until age 50 →
Whereas conscientiousness and agreeableness show a gradual increase over time
People score lower on neuroticism as they get older
Individuals tend to feel less anxious and distressed as they move into midlife
Personality change
Changes in self esteem from adolescence to adulthood: for sample as a whole there was no change in self esteem, however there was a change when males and females were examined separately→ mens self esteem tends to increase while womens tends to decrease
Autonomy dominance leadership and ambition: howard and bray study observed steep decline in male managerial candidates, drop was steepest for those who had a post secondary education→
However mens scores of autonomy, leadership, motivation, achievement and dominance all increased over time
Sensation seeking and impulsivity: declines with age
impulsivity/sensation seeking increased with agre from childhood to adolescence (18-20) then declines as people get older
Decline in impulsivity tends to be much steeper than sensation seeking
Increasing openness and creativity: openness slightly decreases with age,experiences can significantly affect openness
Personality changes across cohorts, assertiveness and narcissism: scores in narcissism increased in american college students,decline of empathy has been reported in the US→
Further evidence to suggest a rise in individualism
Sociocultural factors can shape traits of narcissism, narcissistic traits more likely in individualistic cultures in comparison to collectivist cultures
womens scores of assertiveness rose and fell dramatically depending on the cohort which they were raised
Is volitional personality chage possible?: can people change their personalities eg to be more socially desirable → evidence suggests yes, self improvement may be possible even when it comes to our most hardwired traits
Personality coherence over time
Marital problems: 3 traits shown to predict marital dissatisfaction, the neuroticism of husband, lack of impulse control of husband, and neurotcism of wife
Neuroticsm also makes coping with loss of spouse more difficult →
Emotional stability predicted best outcomes for dealing with death of a loved one
Alcoholism, drug abuse and emotional disturbance: high neuroticsm and low impulse control is risk factor for alcoholism
Low agreeableness and conscientiousness risk factors for alcoholism and drug abuse
Academic achievment: high impulsivity associated with poor education and work outcomes
Conscientiousness is single best predictor of success in school
Health: high conscientiousness, positive emotionality (extraversion) low levels of hostility,and low neuroticism best predictors for living long healthy life
People who married spouses similar themselves showed high personality stability
Chapter 6
Genetics and personality
Human genome: complete set of genes possessed by an organism, contains between 20,000 and 30,000 genes located on 23 pairs of chromosomes
Each gene consists of long strands of DNA
All cells within body contains two sets of human genome on from each parents, except for red blood cells which do not contain any genes
Human genome project: multibillion dollar international research endeavor dedicated to sequencing entire human genome
The manor in which human genes get decoded into proteins is more variable than other species and may account for our differences from rodents
Protein coding genes only make up 2 percent of human genome, was called genetic junk→
We now know genetic junk may have impact on human traits affecting size to personality
Behavioural genetics: the study of genetic infleunces on human behaviour, → very contraversial because they suggest that genetic differences among individuals rather than environment are responsible for shaping core human features
People worry that findings from behavioural genetics will be used or misused to support particular political adgendas →
there is also free will question, how do we hold people accountable if their behaviour was predetermined by genetics
Eugenics: notion that we can design the future of the human species by fostering the reproduction of people with certain traits and discouraging reproduction from people without those traits
Environmentalist view: personality is determined by socialization
Behavioural genetics
Percentage variance: the fact individuals vary or are different from each other and this variability can be partitioned into percentages that are due to different causes
Interested in how genes and environment interact with each other
Heritability: the proportion of observed variance in a group of people that can be accounted for by genetic variance, the degree to which genetic differences in people cause differences in observed features
Heritability formal definition: the proportion of phenotypic variance that is attributable to genotypic variance
Genotypic variance: individuals total collection of genes possessed by each person
Phenotypic variance: observed individual differences ge height weight personality
A heritability of 0.5 means that 50% of observed phenotypic variant is attributable to the genotype, and the other component is the environment
Environmentality: the percentage of observed differences in a group of individuals that can be attributed to environment
Heritability is not constant → if environments can change heritability can change
Nature vs nurture: we are the product of inseparable intertwining of genes and environment
Selective placement: problem in adoption studies where if adopted children are paired with adoptive parents similar to their biological this may inflate correlations
DRD4 gene (dopamine related) associated with novelty seeking risky sex and drug use
Gene environment interaction: differential response of individuals with different genotypes to the same environment
Gene environment correlation: the differential exposure of people with different genotypes to different environments
Passive genotype environment correlation: when parents provide both genes and the environment to children yet children do nothing to obtain that environment
Reactive genotype environment correlation: when parents respond to children differently depending on the genotype
Active genotype environment correlation: when a person with a particular genotype seeks out an environment to match
Epigenetics: the study of how experience can determine how or whether a gene is expressed
Jan 28th lecture
Genes and personality s
Ethical issue of eugenics
Percent of variance: difference between people due to a certain cause → those different causes/percentages are either going to be genetic or environmental
Heritability: amount of phenotypic variants, variants we can easily measure eg height personality that we can attribute to genetic variance
Genetic variance: individual differences in peoples genes
Environmentality: amount of observed variance we can say are due to the environment eg peoples childhood upbringings
Behavioural genetics methodologies: family studies, twin studies
Family studies: genetic relatedness of family members
Parents and children: 50% shared genes
Siblings: 50%
Grandparents and grandchildren: 25%
Closer relatives should have more personality similarity if heritability is true