Download Biological Approach

How We Become Who We Are –
Processes & Patterns of Change
A General Framework for Personality Psychology
Life Events and
Broad Social Contexts
•Latent/Enduring Dispositions
Traits – the broad strokes of how we differ
from each other, eg N, E, O, A, C (& H?)
Biology
“In the Moment”
Occurrent
Cognitions
Objective Environmental
Properties
Social
and
Behavioral
Events
Perceived
Environmental
Properties
Occurrent
Emotions
From first class
Nature and/or nurture – which one is more
responsible for determining “who you are” (in
terms of your personality)?
What are the types of facts/observations that
lead to one conclusion or the other?
Why does this issue even matter?
Personality Development and Change
Processes
• Biological forces and processes
• Environmental forces and processes
Patterns
• “Stage” theories – Freud, Erikson
• Empirically-demonstrated patterns of
personality development/change
Biological Forces and Processes
Affecting Personality
Note: I’ll email scale in prep for a later class.
Please send your scores back to me, so I can
aggregate for class
Biological Approach
Goals
• Understand the way in which your
biological characteristics might affect your
personality.
• Understand “how much” your personality
is affected by your biology
• Understand how we can answer these ageold questions scientifically.
Biological Approach
Outline:
•Brain Anatomy
•Biochemistry (Hormones, Neurotransmitters, Cytokines)
•Genetic Effects, Evolution
Brain Anatomy
At a very general level, certain parts of the
brain are (somewhat) associated with certain
personality characteristics.
How do we know this?
• Case studies - Injuries/Disorders (eg, Phineas
Gage, C. Whitman)
• Brain imaging (PET scans, fMRI)
Brain Anatomy – Frontal Lobes
Phineas Gage (1848)
•Accident
Brain Anatomy – Frontal Lobes
Personality changed – Gage became crude,
uncaring, impulsive, irrational, anti-social
Damasio H., Grabowski T,. Frank R., Galaburda AM., Damasio AR. (1994). The return of
Phineas Gage: clues about the brain from the skull of a famous patient. Science.
264(5162):1102-5,.
Ventromedial region of the frontal lobes on
both sides - causing a defect in rational
decision making and the processing of
emotion
Brain Anatomy – Frontal Lobes
Brain tumour causes uncontrollable paedophilia
NewScientist.com news service
(Research presented at American Neurological Assoc conference, October 2002)
The sudden and uncontrollable paedophilia exhibited by a 40-yearold man was caused by an egg-sized brain tumour, his doctors have
told a scientific conference. And once the tumour had been
removed, his sex-obsession disappeared.
The cancer was located in the right lobe of the orbifrontal cortex,
which is known to be tied to judgment, impulse control and
social behaviour.
Brain Anatomy
Amygdala (part of limbic system)
Brain Anatmoy - Amygdala
Emotional experience - anger, fear,
aggression, sexual responsiveness
How do we know?
• Removal from monkeys - alters aggression,
fear, sex behavior
• Case studies (eg, Charles Whitman)
Neural imaging studies of brain anatomy
and functioning
CT scans, PET scans, MRI,
fMRI – functional Magnetic
Resonance Imaging
SPECT - single-photon emission
computerized tomography
(SPECT)
What are they?
What have we learned?
Neural imaging - what is it? fMRI
Neural imaging - what have we learned?
Big Five traits
Summary of :
DeYoung, C. G., Hirsh, J. B., Shane, M. S., Papademetris, X., Rajeevan, N., & Gray, J. R. (2010). Testing
predictions from personality neuroscience: Brain structure and the Big Five. Psychological Science, 21, 820–828.
http://www.thepsychfiles.com/2010/07/episode-127-video-phrenology-maybe-they-were-on-to-something/
Biological Approach
Outline:
•Brain Anatomy
•Biochemistry (Hormones, Neurotransmitters)
•Genetic Effects, Evolution
Biochemistry
3 Kinds of biochemicals:
• Neurotransmitters, enzymes (nervous system)
• eg - MAO, Serotonin
• Hormones (endocrine system)
• eg - testosterone, cortisol
Biochemistry - Neurotransmitters
MAO (monoamine oxidase) – related to
sensation-seeking and impulsivity
• In monkeys, infants, and adults
Serotonin – related to depression, anxiety
• Prozac influences Serotonin levels
See DeYoung (2010) reading for more on
dopamine, serotonin and personality traits
Biochemistry - Hormones
Cortisol – high levels related to
shyness/inhibition?
Testosterone - related to aggression and
sexuality?
• Some studies show link, but some don’t.
• Also, testosterone levels can be influenced by
experience (Soccer study, Chess study)
A General Framework for Personality Psychology
Life Events and
Broad Social Contexts
•Latent/Enduring Dispositions
Traits – the broad strokes of how we differ
from each other, eg N, E, O, A, C (& H?)
Biology
Brain Anatomy
Biochemicals
“In the Moment”
Occurrent
Cognitions
Objective Environmental
Properties
Social
and
Behavioral
Events
Perceived
Environmental
Properties
Occurrent
Emotions
Biochemistry - Hormones
Testosterone and Sexual Orientation
Williams, et al. (2000). Finger length patterns and human sexual
orientation. Nature, 404, 455-456.
Is amount of in-utero testosterone exposure related to
sexual orientation?
Biochemistry - Hormones
In-utero
testosterone
level
?
Finger length
ratio
Sexual
orientation
??
Biochemistry - Hormones
•720 Adults
Xerox copy of hand (to assess finger length
ratio)
Questionnaire - gender, sexual orientation, # of
older brothers, etc.
Biochemistry - Hormones
•Results:
Females with more “masculine” finger length
ratio (more in-utero testosterone exposure)
were more likely to be homosexual
Not so for males.
So, there is some indication that
hormonal levels are related to sexual
orientation
Biochemistry – Oxytocin
“Love hormone” or “Bonding hormone”
Eg, orgasm, social recognition, pair
bonding, anxiety, and maternal behaviors
https://www.youtube.com/watch?v=_GgGDLGCI4A
But also, violence toward out-group individuals?
Link to personality traits?
Cereb Cortex. 2014 Feb;24(2):479-86.Oxytocin's fingerprint in personality traits and
regional brain volume. Andari E1, Schneider FC, Mottolese R, Vindras P, Sirigu A.
N= 30, blood samples, NEO-PI-R
Biochemistry – Oxytocin
Cereb Cortex. 2014 Feb;24(2):479-86.Oxytocin's fingerprint in personality traits and
regional brain volume. Andari E1, Schneider FC, Mottolese R, Vindras P, Sirigu A.
N= 30, blood samples, NEO-PI-R
Trait
Corr with Basal
Oxytocin Levels
E
.44**
N
-.15
O
.12
A
-.11
C
.05
** p < .01
Biological Approach
Outline:
•Brain Anatomy
•Biochemistry (Hormones, Neurotransmitters)
•Genetic Effects, Evolution
Genes, Evolution, and Personality
To what degree are various personality traits
genetically-influenced? How can we figure this
out?
Are specific traits linked to specific genes?
Do women and men experience jealousy for different
reasons, and if so why?
What would a comprehensive biological model of
personality look like?
Genetic Effects on Personality
Where do individual differences in biology
come from?
• Environment (early experiences)
• Genes
Genotype – underlying genetic profile
Phenotype – actual trait expression
Genetic Effects on Personality
Three topics in “Genes and Personality”
• Behavioral Genetics (to what degree is a trait
inherited?)
• Molecular Genetics (which genes affect which
traits?)
• Evolutionary Psychology (why do we have
certain traits, behaviors?)
Behavioral Genetics
How can we test for genetic effects?
Twin studies, adoptions studies
• If a trait’s level is influenced by genes, then
people who have similar genes should have
similar trait levels.
• The more genetically similar you are to
someone, the more similar you should be to
them on the trait
• Genetic similarity ---> Phenotypic similarity
Behavioral Genetics
Genetic similarity – similarity on the genes
that can differ across people
•
•
•
•
Identical twins (Monozygotic) – 100% sim
Fraternal twins (Dizygotic) – 50% similarity
Parent and child; “regular” siblings – 50%
Cousins – 25%
Behavioral Genetics Study Example
Example - Intelligence
If intelligence is genetically-determined (to
any degree), then identical twins should have
more similar levels of intelligence than
fraternal twins.
Behavior Genetics Study Example
High genotypic
similarity
Identical twins
________
IQ of first IQ of second
Family Twin
Twin
Lower genotypic
similarity
Fraternal Twins_______
IQ of first IQ of second
Family
Twin
Twin
Family 1
110
112
Family 6
97
110
Family 2
102
118
Family 7
101
126
Family 3
103
98
Family 8
106
95
Family 4
90
96
Family 9
113
105
Family 5
95
92
Family 10
130
120
Identical twin corr = .67
High phenotypic
similarity
Fraternal twin corr = .33
Lower phenotypic
similarity
Behavioral Genetics
“Heritability coefficient” – amount of
phenotypic variability that is due to genotypic
variability (Range from 0 to 1)
H = (Identical twin Corr – Fraternal twin corr) x 2
Example
H = (.67-.33) x 2 = .67
So, about 67% of the between-person differences in Intell
arises because of genetic differences
Behavioral Genetics
“Heritability coefficient” – amount of phenotypic variability that is due to
genotypic variability (Range from 0 to 1)
Trait
Height
Blood Pressure
Intelligence
Extraversion
Neuroticism
Impulsivity / Sensation Seeking
Average Heritability
.85
.65
.70
.40
.55
.44
Behavioral Genetics
Problems with this design?
• Identical twins may share more similar genotype AND
a more similar environment than fraternal twins
So compare:
• Identical twins reared together (similar genes, similar
env) to
• Identical twins reared apart (similar genes, dissimilar
env).
Behavioral Genetics
So, for many core personality traits
(temperament?) heritability is around .50.
What to make of these data?
• Genes affect personality
• Genes affect some traits more than others
• Environment affects personaltiy
Molecular Genetics
“Which genes affect which behaviors?”
Molecular Genetics - example
Gene May Link Alcoholism and Depression
y CHERYL WITTENAUER, Associated Press Writer
Original study published in Human Molecular Genetics
ST. LOUIS - Scientists say they've identified a gene that appears to be
linked to both alcoholism and depression, a finding that may one day
help identify those at higher risk for the diseases and guide new
treatments.
Previous studies of twins and adopted siblings have suggested there likely
are genes in common underlying alcoholism and depression, and that the
two disorders seem to run in families. But the lead researcher of the new
study says this is the first report of a specific gene that seems to increase
risk for both disorders.
Molecular Genetics
Goate's team analyzed DNA from 2,310 people from 262 families in which at least
three members were alcoholic. Some individuals in these families were also
depressed alcoholics. Both groups had similar distinguishing characteristics in
their DNA in a region on chromosome 7. Participants with both maladies were
most likely to have the genetic similarity.
Within that region of the chromosome, researchers isolated the CHRM2 gene,
which is involved in attention, learning, memory and cognition. Goate's team
found the gene was strongly associated with both alcoholism and depression.
The association was strongest in those with both disorders, suggesting it's a
susceptibility gene that puts people at risk for developing both diseases.
This is the first time this particular gene has been implicated in depression.
Researchers said probably multiple genes are involved in these two disorders.
Original study published in Human Molecular Genetics.
Molecular Genetics
Complexity of linking Molecular genetics &
Personality
•
•
•
•
Technology
Multiple genes for a trait?
Interactions between genes
Multiple other determinants of traits/behaviors
• We’ll return to the idea of “gene-environment
interactions”
Evolutionary Psychology - overview
We have genetic tendencies that affect our
behavior
Behaviors that are common today are present
because, in the evolutionary history of the
human species, those kinds of behaviors were
helpful in survival and reproduction
Tooby and Cosimedes
Evolutionary Psychology & jealousy
Do men and women experience jealousy
differently? What drives jealousy?
Evolutionary Psychology & jealousy
Study – 202 college students
“Please think of a serious committed romantic relationship that
you have had in the past, that you currently have, or that you
would like to have. Imagine that you discover that the person
with whom you’ve been seriously involved became interested in
someone else. What would distress or upset you more (please
circle only one):”
(A)Imagining your partner forming a deep emotional attachment
to that person.
(B)Imagining your partner enjoying passionate sexual
intercourse with that other person.
Evolutionary Psychology & jealousy
(A) Imagining your partner forming a deep emotional
attachment to that person.
(B) Imagining your partner enjoying passionate sexual
intercourse with that other person.
Gender
A (Emotional)
B (Sexual)
Female
83%
17%
Male
40%
60%
Evolutionary Psychology & jealousy
Follow-up study revealed corresponding
physiological reactions to the two scenarios (Pulse
rate, muscular reactions in the brow, etc) :
•Females - greater phys reaction to emo. infidelity (than
to sexual)
•Males - greater phys reaction to sexual infidelity (than
to emo),
What makes men jealous? Why?
What makes women jealous? Why?
Evolutionary Psychology
Critiques of Evolutionary Psych
Please see book’s discussion
Zuckerman’s model of biology and personality
Supertraits
Extraversion
SensationSeeking
Neuroticism
Traits
Sociability,
Activity
Impulsivity vs Restraint
General
Emotionality
CognitiveBehavioral
Reward
Expectations
Behavioral
Disinhibition vs Inhibition
Punishement
Expectations
Emotions
Positive
Affect
Anger
Cortical
Excitiation vs Inhibition
Psychophysiology
Anxiety
Adrenergic
arousal
GABA
Dopamine
Biochemistry
Genes
Gonadal
Hormones
Serotonin
Norepi,Epi
DBH
MAO
Type B
Genotypes
BZ receptor
agonists
(& inverse
agonists)
Biological Approach
Goals
• Understand the way in which your
biological characteristics might affect your
personality.
• Understand “how much” your personality
is affected by your biology
• Understand how we can answer these ageold questions scientifically.