Understanding human diversity

2 dimensions of diversity

• structural diversity

• individual diversity

structural diversity

demographic composition (age, gender, race, etc.)

individual diversity

differences between people (personality, beliefs, attitudes, skills, etc.)

historical shifts in individual differences research

• variation matters

• measuring variation

• identifying underlying structures

• thinking in dimensions

• explaining variation

• integrating multiple influences

variation matters

recognising that individual differences are scientifically relevant and interesting → not seeing them as a measurement error
beneficial in education and work (e.g. ‘who needs support?’ or ‘who is suited to this role?’)

measuring variation

development of psychometrics
developed standardised tests

began thinking about reliability, validity, and norms

identifying underlying structures

recognising patterns/correlations between characteristics and that they could both be caused by the same underlying structure(s)

thinking in dimensions

shift from thinking about people as belonging to distinct categories to thinking about characteristics as continuois dimensiuons
important in diagnosing
allows for comparing how different two people are

explaining variation

shift from description to explanation (genetic, biological, environmental)

integrating multiple influences

shift from ‘ what is the cause?’ → ‘ what factors contribute to individual differences, and how do they interact?’

self-report measures evaluation

positives:

• cheap

• easy to make large scale

negatives:

• social desirability bias

• acquiescence bias - tendency to agree

experience sampling evaluation

positives

• real world contexts

negatives

• burden on the participants

• those specific times may not be reflective of the participants life

behaviour and performance measures evaluation

positives:

• quantifiable

• objective

negatives:

• ecological validity

• only captures part of a construct

biases which could effect observational studies

expectation bias

halo effect

cultural bias

priming paradigm

a way to measure the unconscious

participant is exposed to stimulus and their response is measured

previous stimuli influences response to later stimuli

2 types of factor analysis

exploratory

confirmatory

hereditability

the proportion of variation in a characteristic within a particular population that is statistically attributable to genetic differences

NOT, how much of a person’s characteristic can be attributed to genetics

pluripotency

the same brain region can contribute to several psychological processes

degeneracy

a psychological function can be supported by multiple brain regions

disturbed processing

brain regions work together, in parallel, rather than operating in a sequential hierarchy

overlapping networks

a brain region can participate in several networks, depending on the task and the context

intelligence - cultural differences

western cultures - emphasis on speed of mental processing and ability to gather & organise information efficiently

non-western cultures - may place more emphasis on social, emotional or practical competences

key figures in intelligence theories and testing

• Francis Galton

• Alfred Binet

• William Stern

• Lewis Terman

• Charles Spearman

Francis Galton

believed intelligence was due to heredity (survival of the fittest)

acknowledged individual differences in intelligence and believed that intelligence could be measured

Alfred Binet

developed first intelligence test

introduced idea of a mental age

William Stern

developed the concept of IQ

IQ = mental age/ actual age (x100)

Lewis Terman

established age norms (how intelligent the ‘average’ person is at each age)

Wechster tests

WAI-5 (latest version) has 5 categories

examples:

verbal comprehension index

working memory index

perceptual organisation index

processing speed index

other theories of intelligence

deviation IQ

Raven’s progressive Matrices

first multi-factor theory

fluid vs crystallised intelligence

three-stratum theory (1993)

CHC - Cattel-Horn Carrol theory

deviation IQ

Deviation IQ = actual test score/ expected score for age (x100)

mean = 100, SD = 15

first multi-factor theory

intelligence has a multidimensional structure

7 primary abilities:

• associative memory

• numbers

• perceptual speed

• reasoning

• spatial visualisations

• verbal comprehension

• word fluency

fluid vs crystallised intelligence

fluid → ability of abstract reasoning

crystallised → acquired knowledge and skills

CHC

development of three-stratum theory - in that it is further integrated

made simpler - to be practical for psychometric testing

measures most important factors

heritability - intelligence

study found that MZ twins who are raised together had strongest positive correlation. Sibling who raised apart has weakest → evidence for an interactionist approach

gen-environment correlation vs gen-environment interaction

correlation → people’s genetics will effect the environments they put/find themselves in

interaction → influence of genes on a trait is dependent on the environment and can change from situation-to-situation/environment-to-environment

genetics as an explanation for intelligence criticisms

• representativeness → do adoption and twin studies represent the population?

• complexity of genetics - we don’t know how genetics influence intelligence

• assortative mating → people are likely to mate with similar people

neurobiological factors for intelligence

• larger brain → through evolution

• cortical thickness → pattern of cortical growth in childhood is related to increased IQ

• neural highways:

- white matter connectivity

- brain network linking frontal and parietal lobes

environmental factors for intelligence

• family size and birth order

• breastfeeding

• prenatal health

• socio-economic status

• education

early conceptualisations of personality

Galen - believed it depended on a balance of blood, yellow bile, black bile, and phlegm

Freud - tripartite model - dependent on the unconscious (id, ego, superego)

key theorists in personality

Gordon Allport

Henry Murray

Raymond Cattell

Gordon Allport

saw personality as a dynamic organisation determined by adjustments to the environment

emphasised traits as the fundamental unit of study for personality

proposed proprium - consists of all aspect of personality and brings consistency

Henry Murray

personality is constituted by conscious and unconscious conflicting

primary motivator (need) interacts with situation - ‘unity Thema’

20 needs separated into primary and secondary

primary → needs for survival

secondary → emotional satisfaction

prepotency → unsatisfied needs determine behaviours

Raymond Cattell

surface traits → represent clusters of manifest variables

source traits → underlying factors determining surface traits

utilised factor analysis and publishes the sixteen personality factors questionnaire

Eysenck’s hierarchial model

specific responses (to a one-off occurrence) are repeated to make habitual responses (how you usually respond)

collections of habitual responses = traits

using factor analysis, he found certrain traits are fundamental = ‘super traits’

super traits

extraversion

neuroticism

psychoticism

five-factor model

OCEAN

the HEXACO model

argued for a sixth characteristic (honesty-humility)

the general factor of personality

a single factor explains the big 5

may reflect a psychobiological disposition contributing to social and personal adjustment

evaluation:

correlation may be due to social desirability bias

adoption studies - personality

larger correlations between children and biological parents (compared to adoptive parents) (Loethlin et al)

identical twins reared apart showed correlations for extraversion and neuroticism (Hershberger et al)

genetic influence was substantial for openness and conscientiousness but not agreeableness (Bergeman et al)

problems with heritability estimates

• additive genetic actions → different genes work independently

• dominant genetic actions → dominant genes supress expression of recessive genes

• epistatic genetic actions → certain genes determine whether other genes will be expressed or supressed

Esyenck’s biological model of personality

2 types of neural mechanisms

• excitatory - keep you alert, active, and aroused

• inhibitory - causes inactivity and low energy

extraversion is linked to arousal circuit responding to incoming stimuli

introverts are over aroused and extraverts are under aroused

neuroticism is linked to arousal circuit responding to emotional stimuli

neurotics more aroused, emotionally stable individuals are less aroused

Gray’s reinforcement sensitive theory

personality is based on interactions between 3 basic systems in the brain

• behavioural approach system - motivated to seek rewards

• behavioural inhibition system - motivated to avoid punishment

• fight/flight/freeze system - response to threat

link to Esyenck - introverts are more aroused due to punishment anxiety

Cloninger’s psychobiological model

4 dimensions of temperament and 3 dimensions of character

temperament dimensions manifest early in life - involve individual differences in response to reward, punishment, danger

character dimensions mature in adulthood and determine social effectiveness

temperament and character dimensions

temperament

• novelty seeking

• harm avoidance

• reward dependence

• persistence

character

• self-directedness

• cooperativeness

• self-transcendence