Week 5 - Biology Flashcards
(29 cards)
What was the first biological explanation of traits?
Hippocrates, then Galen “The Four Temperaments”
“The dominant bodily fluid is associated with a unique personality type, but the perfect temperament is a balanced temperament, a perfect mix of bodily fluids”
Phlegm = phlegmatic = shy, reserved, emotionally stable
Yellow bile = choleric = impulsive, restless, irritable
Blood = Sanguine = bold, confident, optimistic, courageous
Black bile = melancholic = sad, depressive, brooding, pessimistic
What is the different between physiognomy and phrenology?
- Physiognomy
one can infer personality traits from observing FACIAL FEATURES - Phrenology, 1835
one can infer personality traits from observing bumps in the brain - a “cautiousness located at spot number 12 in the brain”
Who predicted that we could determine criminals?
Lombroso, 19th century
Criminal behaviour is in part genetic, can infer from facial and skull features, mix of evolutionary theory, physiognomy and phrenology
Argued some people, about 30% are evolutionarily “born criminals”
What was hypothesised about body types and personality?
- Pykics / obese types = cheerful, happy, when unwell become bipolar
- Leptosome / thin types = shy, introverted, reserved, more likely to become schizophrenic
- Athletic / muscular types = assertive, courageous, more likely to become epileptic
What did Sheldon argue about body types and traits?
- Ectoprohs = reserved, shy, active
- Mesomorphs = strong bodies, rectangular aggressive, courageous, impulsive,
- Endomorphs = rounded, bigger bodies, pleasant, likeable, easy-going, friendly
What’s the problems with linking body types and traits?
- Methodological and error problems
- unclear directional cause: what cause between body and personality is, potentially people treat people in a certain way
Is there any support for older theories of biological origins of personality?
- Some support for phrenology,
Personality traits tend to localised and related to brain structure and volume
- Some support for physiognomy: males with wider faces tend to be more aggressive compared to narrower faces
- Some support for criminal behaviour: can differentiate criminal from non criminal faces, couldn’t really distinguish between violent and non-violent criminals, easier to detect non-violent
What are the 3 aspects of the Contemporary Biological Approach
in personality?
- CNS
- NTs and hormones
- Evolution?
What 2 areas in the CNS affect personality?
- Frontal lobe damage often leads to personality changes, sometimes significantly so, become more unpredictable, impulsive, cannot plan,
- Frontal cortex is related to planning, self-control and damages causes deficits in these areas - Overactive amygdala is correlated with fear, anxiety, neuroticism and BPD “an aversion to novelty, strangers,
- People shy as babies, showed higher amygdala activity in shown pictures to strangers
Do brain regions correlate with personality?
(116 people with Big 5 personality scale and structural brain scans)
- Extroversion = GMV in medial frontal cortex, encodes reward in stimuli, related to sensitivity to reward in the environment
2/ Neuroticism = dorsomedial prefrontal cortex, involves in emotional regulation, threats, punishment sensitivity,
3/ Conscientiousness = higher GMV in middle frontal gyrus, involved in planning, self-regulation
- Agreeableness = less GMV in left posterior superior temporal sulcus, more GMV in cingulate, interpreting actions, beliefs and intentions of others,
Openness = no significant effects on brain regions
Which big 5 trait was no correlated to any specific brain regions?
Openness
What are the 3 main hormones involved in different personality changes?
- testosterone - aggression
- cortisol - stress, neuroticism
- Oxytocin = less lifelong aggressiveness, love hormone
What are the 3 main hormones involved in different personality changes?
- Dopamine = extroversion, impulsivity
- Serotonin = mood regulation, inhibits impulses, low serotonin = neuroticism, depression, sensation seeking (criminal behaviour, serotonin depletion syndrome)
- Norepinephrine = related to flight/fight and neuroticism
How are the big 5 traits linked to specific NTs?
- Dopamine = Extroversion & openness
- Serotonin = Emotional stability, agreeableness and conscientiousness
Do NT levels change in the environment?
YES
- brain chemicals can affect and can be affected by changes in the environment and life experiences
What are some examples of how NT levels change in the environment?
Testosterone increases OR decreases in the following environments:
- Women who take more traditionally male jobs
- in athletes and sports fans increases in winners and decrease in losers in competitions
- getting to drive a fancy car and decreases in old worn down cars
- before marriage, stable during marriage, increase after divorce
- Scent of monkey child dampens levels of testosterone in monkey fathers
Do NTs shape personality traits?
- NO - NTs don’t seem to cause personality traits, but rather life experiences and genetics seem to shape BOTH personality traits and NT levels
Some argue our genetics causes use to have PARTICULAR levels of NTs and hormones
What % of genes do MZ and DZ twins share in the environment?
MZ = 100%
DZ = 50%
Evidence for genetic causes to personality?
- Triplets separated at birth found a lot of similarities despite having different upbringing and life experiences
- Separated twins found insane similarities in their interests, likes, dislikes, and holiday choices
How is the heritability quotient calculated?
MZ and DZ twins are given the same self-report test, and scores of the twins are compared by calculating the correlation coefficient
Heritability quotient = (rMZ - rDZ) x 2
MZ = 0.6 - DZ = 0.4 = 0.2 * 2 =
Heritability = 40%
What is the candidate gene approach?
exploring the prevalence of specific genes in a population high or low on a particular trait
Examples
DRD4 = linked with approach related traits, affects dopamine, extroversion
DRD2 = impulsivity, substance abuse, obesity
COMT = extroversion, reasoning, dopamine in PFC
What are hertitability quotient of Big 5 traits?
Big 5 genetic component: openness = 0.57, extroversion = 0.54, agreeableness = 0.42, conscientiousness = 0.49, neuroticism = 0.48
Schizophrenia = 0.8, phobias = 0.2-0.40, authoritarianism = 0.5-0.64
Significantly more similarities in genetic individual twins than DZ twins
Limitations of the candidate gene approach?
- often failed to reproduce specific results
- a single gene cannot be directly related to personality
What are Genome Wide Associations Studies (GWAS) and how do they work?
- Genetic info of thousands-millions of individuals
- Explores relationships between millions of single-nucleotide polymorphisms (SNPS) and phenotype traits
- SNPS differentiate us at a genetic level, small but significant effects between single SNPS and traits, SNPs are additive
- SNPs are combined to genome-wide polygenic scores (GPS) that may be linked to a particular trait
