Lecture 1 -> Introduction to personality and biological approaches Flashcards
(22 cards)
Why combine personality and mental health together?
Personality and mental health
- both deal with behaviour
- behaviour on opposite ends of a continuum
Normal <-> mild <-> moderate <-> psychological disorder - less severe <-> psychological disorder - more severe
What is personality?
An individual’s unique and relatively consistent pattern of thinking, feeling and behaving
Personality as individuality
Individual’s personality determines:
- how different they are from others
- how they behave in different situations -> context dependent
Approaches to personality
Biological
Behavioural
Social
Humanistic
Psychoanalytic
Trait theory - seen as the most major approach and the only one that is considered important in today’s society (the big 5)
Early approaches
Hans Eysenck (1912-1997)
- identified 2 primary personality traits
~ Extraversion-introversion
~ Neuroticism (emotional stability)
- these factors are indepdent from each other -> they are seen as too few ideas to be able to describe personality as a whole
Extraverts are outgoing, impulsive, sociable
Intorvers are quiet, revered and distant
People high in neuroticism are unstable or highly emotional, easily upset and angered
Individuals low on neuroticism are less prone to mood swings
Eysenck attuned biology influences personality
- consistency of extraversion-introversion over time
- cross-cultural research indicator similar personality dimensions
- genetics play vital role in determining personality
Biological Approach
Inherited predispositions which determine personality
Physiological processes explain differences in personality
A lot of thick backing comes from twin studies, however they typically aren’t carried out anymore because they are considered unethical
Genetic Influence
Genetic studies are used to estimate the heritability ofna characteristic
The three main methods for assessing genetic heratibity of personality: family studies, twin studies and adoption studies
Twin Studies
Fratneral twins - disygotic
- ~ 50% shared genetics but born at the same time so shaped by same environment - same genetic similarity that non-twin siblings share with each other
- dissimilar personalities
Identical twins - monozygotic
- 100% shared genetics
- similar personalities
Results are given in the measure of concordance (similarity)
Personality Dimensions:
MZ Twins:
Extraversion = 0.56
Neuroticism = 0.53
DZ Twins:
Extraverison = 0.28
Neuroticism = 0.13
Heritability estimate:
Extraversion = 56%
Neuroticism = 80%
Genetics vs Environment
Researchers may study mz twins that have been reared apart from each other
- Minnesota Study of Twins Reared Apart, which involved the medical and psychological assessment of identical and fraternal twins separated in early life and reared apart (Pedersen et al. 1988)
MZ Twins reared together:
Extraversion = 0.54
Neuroticism = 0.411
MZ Twins reared apart:
Extraversion = 0.30
Neuroticism = 0.25
DZ Twins reared together:
Extraversion = 0.06
Neuroticism = 0.28
DZ Twins reared apart:
Extraversion = 0.04
Neuroticism = 0.24
Certain perodsnality traits might have more genetic influence
- e.g. neuroticism
Environment likely plays a large role in development of personality
However, it has veer suggested that twin studies might actually overestimate the role of genetics, particularly because identical twins have more similar environments that same-sex fratneral twins
Reserach also shows that identical twins are treated more similarly by their parents, spend more time together and have the same friends, meaning their environmental expeirnce comprises a greater portion of each other’s social environment than does fraternal twins
Consequently, if genetic heritability estimates are usually larger in twin studies than in adoption studies, then some of the similarity that is attributed to genetic influence may not be correct
Genotype
Genetic makeup of an individual - a genetic “blue print”
Contains 23 pairs of chromosomes
Made up of pairs of alleles (e.g. gene variants) provided by parents
Image description:
Cell - packed in the. nucleus of the cell are 24 pairs of chromosomes that represent your unique genotype
Chromosome and gene - a gene is a segment of the DNA that contains the genetic instructions for making a particular protein
DNA - each gene is a segment of DNA. The twisted strands that make up a DNA molecule resemble a spiral stair case (a double helix structure)
Epigenetics
Genotype doesn’t equal you
Epigenetics:
- influence of environment on gene expression - e.g. through lifestyle habits such as smoking or alcohol assumption or trauma such as family member loss
- alters structure of DNA
- this altered strcutre can be passed on to your children
Phenotype:
- observable expression of genetics - an outwards manifestation of the individuals that is the sum of all the atoms, molecules, cell,s tissues and organs
- most obvious example is appearance
- e.g. height, eye colour, blood type, personality
- genetics and environment feeding your personality
Genetic influence
Twins
- share similar environments from birth
- biology as source of personality
~ higher genetic similarities = similar personalities
Limitations:
- 100% genetic similarities share roughly 50% of personality
- environment may account for remainder of variability
Critiquing Eysenck
Jeffery Alan Gray (1934-2004) - how do we deal with emotional stimulation - reinforcement sensivitiy theory
Boils down to the view that biological mechanisms move towards things they desire and away from things that worry them or they fear
- introverts and extraverts differ in how they respond to emotional stimuli
- introverts quickly aroused when exposed to external stimulation therefore they avoid them so they don’t face these unpleasant emotions whereas extraverts are better with this
- Extraversion -> sociability
- however, maybe there is something beyond this
- sensitivity to stimulation -> extraversion -> sociability
Reinforcement sensitivity theory
The human brain has 2 behavioural systems underlying indivudal differences in sensivity to reward, punishment and motivation:
- behavioural approach system (BAS) - stimuakte reward system (extraverted) - comprised of motivations to approach
- behavioural inhibition system (BIS) - avoid potential consequences (highly neurotic)
BAS vs BIS
Behavioural approach system:
- tendency to seek rewards and view events as having potential for rewards -> impulsive
- seek out impulsive, rewarding behaviour
- engage in emotionally intense situations (e.g. spending lots of time with friends, events with large crowds, lots of socialising)
Behavioural inhibition system (BIS):
- tendency to avoid punishment and vice events as having potential for punishment -> highly anxious
- avoid emotionally intense situations (e.g. spending lots of time with friends, events with large crowds, lots of socialising)
- anxiety
Individuals vary in strength between these systems -> brain mapping techniques show evidence for this theory
BIS/BAS by any other name
Behavioural approach system (BAS)
- approach motivation
Behavioural inhibition system (BIS)
- withdrawal motivation
- avoidance motivation
Are you BIS or BAS?
How do you spend your spare time?
BIS
- you may go on a long walk to reduce arousal after a long day
- you likely feel anxious in a crowd of people
BAS
- it probably never occurs to your to take a long walk b y yourself
- you feel relaxed in a crowd of people
Frontal lobe
Phinneas Gage (1823-1860)
- railroad foreman
- explosion sent iron rod through skull
- damaged frontal lobe of brain
- survived
Demonstrated changes in personality after this event
- planning behaviour _> he become very impulsive
- emotional control -> he became much more violent and aggressive
- behavioural inhibition -> he used much more offensive language after the injury
Demonstrated the importance of frontal lobe in personality
Measuring personality
Sensitivity to stimualtion
- introverts and extraverts offer in how they respond to stimuli
- introverts are quickly aroused when exposed to stimulation
~ brain differences in response to emotional stimuli
Electroencephalography (EEG)
- measures electrical activity of brain’s surface
- brain activity useful in identifying tidying personality
~ no social desirability bias
~ non-invasive
Differences in activation between right and left frontal lobes
- higher activation in left = higher BAS
- higher activation in right = higher BIS
Activation naturally differs
Differences stable over time
- left frontal lobe = extraversion
- right frontal love = introversion
Clinical applications
Left frontal cortex
- depression (inactivation)
- bipolar (sporadic activation)
Right frontal cortex
- anxiety disorders (activation)
Is personality hardwired?
Orbitofrontal cortex (OFC)
- essential part of personality
- processes emotional information
- decision making
- assigns value to decisions - processing reward and punishment
~ “this might not end well…”
~ “this will work”
Biological approach
Strengths:
- provides genetic account as source of indivudal variability - e.g. biological relations within mental health conditions such as sz
- empirically supported neural indicators of personality
Limitations
- assumptions that biology is primary driver of personality
- assessing personality via biology is not the easiest route
