Neuroscience and Personality
[other biological theories]
Relationship of personality and changes in:
bodily responses: everything but the brain
Brain structures: refers to the various areas of the brain; also looking at the relative size
of the areas. As well as differences in areas according to diff personalities.
Brain activity: transmission of various signals throughout the brain.
Biochemical activity: transmission of the signals facilitated by neurotransmitters.
Nervous system: major divisions of the nervous systems. The feverous system is
divided into two divisions: the central nervous system (CNS) which comprises of
the spinal cord and brain; and the peripheral nervous system which comprises of
the somatic (the body) nervous system and the autonomic (without conscious
thoughts-automatic) nervous system.
The sympathetic nervous system is referred to the fight or fight system… comes
into play when you feel threatened. What is does, is that it dampens down the
other un-needed parts of the body and pays more attention to the parts of the body
which would allow for flight. (heart rate increases, breathing more rapid and
deeper for more oxygen, skin becomes cold and sweaty, pupils dilate, blood
diverted to skeletal muscles, liver releases more glucose into the blood, to supply
the muscles with more blood.(It has sympathy for you)
Parasympathetic nervous system is the opposite. I calms things down, may feel
like throwing up.
Autonomic nervous system: increase heart rate, bodily tem and blood flow, skin
Bodily Responses: MeasuringANS activity (common measures---i.e. liar detector tests)
Body temp and blood flow
Skin conductance (GSR): perspiration on skin, device detects how much electricity the
Electromyography (EMG): measures non-visible muscle movements.
Brain Structure (how to measure it)
Measures of brain structures: static differences in relative size and weight and cell
numbers of brain parts.
Main ways of looking at brain structures are CT and MRI.
Static differences in relative size and weight and cell numbers of brain parts
Computerized tomography (CT) scan
Magnetic resonance imaging (MRI)activity
Cortical stimulation: attaching electrodes or implants to the brain, normally done to
EEG: the cap with electrodes fastened to it, nothing going into the grain… looking at
electrode activities through the skull to the bone.
PET: given a low level of glucose and radioactivity; to make sure the scan can pick it up
(they us radioactivity) fMRI: shows you the activities in the brain whereas MRI only looks at the
activities.(brain imaging research).
TMS: Transcranial magnetic stimulation. Very similar to cortical stimulation but brain
does not need to be opened up, it only disrupts activities in the concentrated areas of the
Biochemical activity: primarily relates to neurotransmitters: chemicals released by
neurons to excite next neuron into action, or inhibit it.
Dopamine, serotonin (linked to depression too little)
Norepinephrine and epinephrine are also considered stress hormones. Her job is to
increase blood flow to muscles by increasing hear rate and blood pressure.
Research example (TED X east): Helen Fisher-biological anthropologist- personality and
Important Biological Theories of Personality
Esynck‘s PEN model: neuroticism, extroversion, and psychoticism. Developed this as a
theory because he believes there would be biological bodily systems that would account
for people differences on the three factors.
Evidence: cross-cultural universality; consistent over time; heritability (genetic or
biological going on)
Eysenck: introverts: greater cortical of arousal, space in ARAS; should be present
in sleep… only difference in response to moderate stimulation.
Eysenck: Neuroticism= stability of SNS and vulnerability of negative emotions; HM:
increase in heart rate in response to intense stimuli; I‘d do as well; HN, but not I: greater
startle response to scary pictures.
Overall, HN more sensitive to negative emotions, but not arousing situations, as I‘s are.
Introverts are more sensitive to arousing situations.
Not sufficient support for Eysenck hypothesis that N is related to SNS activity.
Reinforcement Sensitivity Theory (RST): has to do with different neurological systems in
Gray‘s (1972,1990) reinterpretation of Esynck‘s theory
Neurological Systems: think: sets of neural networks.—Fight-flight-freeze system (FFFS)
(FFFS): similar to sympathetic nervous system. The brain and the nervous system.
Behavioral approach system (BAS): more optimistic and impulsive. Risk failure in order
to gain an award.
Behavioural inhibition system (BIS): resolves conflicts, anxiety before resolution. When
it becomes activated, the person will be more sensitive to punishment, and negative
The theory proposes that individual difference in relative sensitivity of systems.
Temperament: not the same as the temp models learnt.
Factors: Neuroticism, extraversion, psychoticism
Consistency over time
Introverts: greater cortical of arousal, spec inARAS Should be present in sleep
Only difference in response to moderate stimulation
Neuroticism = stability of SNS and vulnerability of negative emotions
HN: increase in heart rate in response to intense stimuli
I‘s do as well
HN, but not I: greater startle response to scary pictures
Overall, HN may be more sensitive to (-) emotions , but not arousing
situations as I‗s are
Not sufficient support for Esynck‘s hypothesis that neuroticism is related
to SNS activity
Reinforcement Sensitivity Theory (RST)
Gray‘s (1972, 1990) reinterpretation of Esynck‘s theory
Think: sets of neural networks
Flight-fight-freeze system (FFFS)
Behavioral approach system (BAS)
Behavioral inhibition system (BIS)
Anxiety before resolution
Individual difference in relative sensitivity of systems
Reinforcement Sensitivity Theory Systems
Key Predictions of RST
Individual differences in reward sensitivity
Individual differences in learning
Reward sensitivity example
Prediction: Brains of high and low BAS people respond differently to food
BAS drive significantly accounted for signal differences in five brain areas related to
visual food cues
Larsen et al., (2003).
Colour naming task (moderate difficulty: average performance 50%)
• Condition 1: Start with $10, punished for incorrect or slow responses - all ended with $5
• Condition 2: Start with $0, rewarded for correct and fast responses - all ended with $5
• Those high in BAS did better in Condition 2,
• Those high in BIS did better in Condition 1
The Zinbarg and Mohlman Study (1998)
Results: RST prediction supported Temperaments
Three clusters of related personality traits:
+ Emotion, reward sensitivity, sociability, social rewards, approach
Negative emotion, anxiety, punishment sensitivity, withdrawal
Psychoticism, sensation/ novelty seeking, lack of
See table 7.2 in text
Neurological Correlates of Temperaments
Difference between emotion expression and response to emotions
Extraverts: More (+) emotions, stronger reactions than I
High N : more (-) emotions, stronger reactions than LN
Positive and negative emotions are separate dimensions, not opposites
Correlations of Cortical Thickness
Introversion is correlated with thickness of three sections of the right (but not the left)
Could be a function of the lowered social inhibition of extraverts (why the area is
Keep in mind that more grey matter does not equal functionality
HN correlated with less volume in left cortex, compared to LN
What have we learned from the neuroscience of personality?
The jury is still out!
Need to think in terms of brain system, not just brain parts
Need to move beyond correlation methods
Central principle: mental phenomena can be described by interconnected networks of
Neurons in the brain communicate with one another through elaborate networks
Connectionist networks (or artificial neural nets) are special computer programs that
simulate biological networks
Mental processing seen as the dynamic and evolving
Driving Forces in Personality: divided into two parts that Freud proposed.
Eros: the life instinct, sexual and hunger needs in every person. Libido is the energy behind this
Thanatos: the death instinct;
Structure and Dynamics of the Psyche
Tripartite model of the psyche: 1. Id: original and most primitive part
2. Ego: realistic aspect – satisfies demands of id and keeps it in check
3. Superego: internalization of society‘s values-consist of conscience and ego-ideal.
Does the Structural Model hold up to empirical support?
No evidence about proposed division of parts
Ideas of conflict and behavioral compromise among forces that remains important
Anxiety caused by id-superego conflict
Unconscious aspect of ego attempts to defend ego from this conflict
Repression: impulse prevented from reaching consciousness
Suppression: pushing impulse down
Sublimation: transforming id impulses to more acceptable ones
Projection: ascribing undesirable impulse to others
Rationalization: giving a rational explanation
Intellectualization: uncoupling thought and feeling
Undoing: attempts to nullify an action or thought
Reaction formation: converting an unacceptable impulse into its opposite.
An Example of Reaction Formation:
byAdams, Henry E.; Wright, Lester W.; Lohr, BethanyA.Journal ofAbnormal Psychology. Vol
105 (3),Aug 1996, 440-445.
Agroup of homophobic men and a group of non-homophobic men were exposed to sexually
explicit erotic stimuli consisting of heterosexual, male homosexual and lesbian videotapes, and
changes in penile circumference were monitored. Only the homophobic men showed an increase
in penile erection to male homosexual stimuli.
Theory of Psychosexual Development
People pass through stages
Conflict/trauma results in fixation on this conflict
Stages of Psychosexual Development
Oral aggressive character: envious, exploitativeg, not competent
Anal retentive character: obstinacy, orderliness, rigidity, frugality
Anal expulsive character: emotional outbursts, disorganization, generosity, rebelliousness Phallic
Phallic character in males: reaction to castration fear – reckless, bold behaviors
Phallic character in females: continual striving for superiority over men
Genital character: mature and capable of adult intimacy
Problems with Freud‘s
Freud: no significant development in id impulses of erogenous zone
Current thinking: important time of physical cognitive, social, and emotional development
Freud: all stages must be successfully handled to navigate adulthood
Current thinking: no clear support for predicted outcomes if all stage challenges not met
Biased methods and sampling
Inadequate developmental proof for Oedipal complex
Gender differences in morality not supported
Personality fixed and unchanging
Focus on sex and aggression
Freud‘s Theories Today: 5 Postulates
Attachment Theory Basics
Warm, intimate, relationship with primary caregiver essential
Impacts emotion regulation, mental health
Internal working model created
Model of relationships
Model of other
Model of self
Ainsworth, following Bowl by (1978) InfantAttachment Styles
Secure: may or may not cry, greeting or full approach at return, easily comforted.
Avoidant: may or may not cry, little or no eye-to-eye contact at return, no greeting; atrial
Anxious/Ambivalent: distress by separation, passive or angry at reunion, difficult to comfort
Aspects of attachment may be transferred to romantic and peer relationships:
Proximity maintenance: resistance to separation
Safe haven associated with an attachment figure
Are Romantic RelationshipsAttachment Relationships? (Fraley, 2010) If so:
We should see same attachment patterns
Adult relationships should work in same ways
Continuity in attachment style
Hasan and Shaver (1987) interviewed 600+ adults.
Asked them to choose which best described their significant relationship
Does adult attachment the same way? Airport study (Fraley & Shaver, 1998)
Observers coded behaviours of couples
Couples separating should show more attachment behaviors
Separation behaviors should match attachment style
ASampling of Behaviors Exhibited by Separating
Before boarding, he reads the newspaper and she leans her head on his shoulder
Both hold each other for approximately 5 min
She stands on her tip-toes to give him a kissrain)
Tears in eyes; both members wipe the other's tears away
She is still at the window 20 min after the plane leaves
Extended hand stretch
He leaves before she boards the plane but watches her from a distance without her knowledge
He kisses her head several times
He leaves quickly
She walks away crying
Long hug; both are crying
She whispers "I love you" to him as she boards
Prolonged hug at the gate
She, in a comforting manner, strokes his face
Many behaviours of separating adults for maintaining contact
Ex: hold onto, follow, and search for their partners
If not separating, attachment behavior fairly subdued
Functional dynamics of attachment appear similar in adulthood
Regulation of these behaviours associated with attachment style
Ex: avoidant adults showed much less attachment behavior than less avoidant adults
More evidence of for similarity
Adult‘s see (+) caregiving qualities, as most "attractive" in potential dates
Secure adults more likely than insecure to seek support from partners, and to provide support Attributions insecure individuals make re: partner's behaviour during conflicts exacerbate
Continuity ofAttachment Style
Childhood attachment style is weakly related to adult romantic attachment style
r = .39
Early internal working models modified by experiences and events
Why does this matter to us?
Attachment patterns related to range of (+) outcomes in adults
Secure adults: less defensive behaviors;
Insecure adults: less tolerance of out-group members, humanistic values, compassion
Why does this matter? AdultAttachment and personality
Personality and Genetics
(Relevant) Cell biology basics
Cell nucleus contains DNA
Carries genetic information
Controls growth and development
23 pairs of chromosomes
One gene = _______________?
Gene expression: genotype vs phenotype
Genotype = specific genetic makeup
Phenotype = how genetic makeup is expressed
Forms of gene expression
• one dominates
• Co-dominance and incomplete dominance
• neither dominant, or one dominant - doesn‘t hide effects of other
• Co-dominance: both expressed
• Incomplete dominance: combination expressed
• Many pairs of alleles create expression
Role of Environment
=Genotype + environment
Impact of environment depends on genotype
Example: Religious upbringing reduces influence of genetic factors on disinhibit ion. Genotype-Environment Correlation
Differential exposure of individuals with different genotypes to different environments
Passive: Parents provide both genes and environment to children.
Child‘s verbal ability and the number of books in home
Reactive / evocative: Parents (or others) respond to children depending on the genotype
Baby likes for cuddling and mother‘s cuddling behavior
Active: Person with particular genotype seeks out environment
High sensation seekers expose themselves to risky environments
Passive decreases with age, active increases
Genotype-environment correlations can be positive or negative
Attempt to determine % of individual differences in a trait due to genetic and % due to
Determine the ways genes and environment interacts and correlates
Determine what relevant environmental factors are.
Heritability: amount of individual difference in trait due to genetic differences.
Environmentality extent to which individual differences are due to environmental differences
Misconceptions about Heritability
Heritability CANNOT be applied to single individual
Only applies to group-level variation
Heritability NOT constant or immutable
Environment homogenous? - Heritability higher
Environmental variations increase - heritability will be lower
Even highly heritable traits modifiable by environment.
Heritability NOT a precise statistic – think estimate
Behavioral Genetics Methods
Selective Breeding—Studies of Humans‘Best Friend
Can only occur if a desired trait is heritable
Done using animals
Ex: depressed mice
Correlates degree of genetic overlap among family members with similarity in trait
If trait is highly heritable, those more closely related should be more similar. Problem: Members of a family share elements of the environment—confounds genetic with
Thus, family studies never definitive
Estimates heritability by seeing if MZ twins are more similar than DZ twins
Positive correlations on traits between adopted kids and parents - environmental influence
Positive correlations between adopted children and genetic parents - genetic influence
Adoption studies avoid equal environments assumption
Assumption adopted children and their (adoptive and genetic) parents are representative
Problem of selective placement of adopted children
Design that combines strengths of twin and adoption studies = twins reared apart
Shared Environmental Influences
Aspects of family environment generally same for all
Examples: # books in home, presence/absence of TV, quality and quantity of food, parents‘
values/attitudes, school, church
If phenotype influenced solely by shared environment...
MZ twins together: r = 1.00
DZ twins together: r = 1.00
Sibs together: r = 1.00
Non-shared Environmental Influences
Ex: treated differently by parents, different friends, different teachers, some go to camp
If trait influenced solely by non-shared environmental influences
MZ twins together or apart: r=0
Same for DZ twins and for sibs
Heritability of Traits
For each FFM factor 35%-65% variability due to heritability
For most traits, environment has major influence, but influence is primarily from non-shared
For most traits, shared environment has little impact
TexasAdoption Study (large, well controlled)
Time 1, children‘s IQ significantly correlated with both bio mom (.23) and adoptive mom
Time 2, children‘s IQ significantly correlated only with bio mother (.26).
Other Research on Intelligence
Near 0 correlations between biologically unrelated siblings
MZ reared together r = .76
MZ reared apart r = .77
DZ reared together r = .22 DZ reared apart r = .32
Intelligence and Personality Compared
Heritability higher for IQ than personality
Example: Correlations for MZ twins are higher for IQ (.76) than personality (.50)
Shared family environment not an important influence on either IQ or personality
Study of heritable changes in gene function that occur without change in DNA sequence
Regulation and Motivation: Self-Determination Theory
We want to know what drives people, and how people differ in this regard
Psychodynamic theories are essentially motivational
The Humanistic Tradition in Psychology:
Reaction to reductionism of behaviourism and pessimism of psychodynamics
View individual as active system with an inherent propensity for growth and the
resolution of psychological inconsistencies
Optimal functioning allows both increasing complexity and integration
Abraham Maslow: Pyramid of needs. His idea was that whatever needs the person is at,
that does will be the motivation.
Carl Rogers: unconditional positive regard; being accepting of people…not necessarily
excepting the behaviour, just the person.
SDT (self-determination theory) rooted in:
-Humanistic tradition: emphasizes responsibility, growth
-Actualizing tendency: motive to actualize growth and bring about positive change
-he Fundamental Psychological Needs:
Relatedness: The need to feel close to others and emotionally secure in ones
relationships; the sense that significant others care about ones well-being.
Competence: feeling that you can reliably produce desired outcomes and or avoid
negative ones. This requires: understanding of the relationship btw behaviour and its
consequences (outcomes expectations) and you have to feel you are