Midterm 2 Flashcards
Ideological concerns?
Research used.misused to make ideological point
Eugenics?
- Is the notion that we can design the future of the human species by
- Fostering the reproduction of people with certain traits
- Discouraging the reproduction of people without those traits
Heritability?
- extent to which genetics predict behaviour or trait
- How much do genetic differences among individuals cause differences in something, such as height, extraversion, or sensation seeking.
inherited?
Behaviour or trait is determined by genes alone
Heritable vs. Inherited
- Physical features (such as height) are largely heritable, but not inherited
- Example: if both your parents are 5’2”, it doesn’t mean you will be exactly 5’2”
Our genes?
- 90% of genes inherited are same across species (all human share these)
- 10% differ across species
Genotypic Variance?
Genetic variance that is responsible for individual differences in the phenotypic expression of specific traits
Environmentality?
Percentage of observed variance in a group of individuals that can be attributed to environment
Cake Metaphor?
- Cake metaphor: You bake a cake with flour, sugar, eggs, and water
Is the finished cake caused more by the flour or the eggs? - Both needed, combined and cannot be separated from finished cake
What Heritability Means?
- Heritability estimates are tied to a place and time
- If everyone in a population has exactly same environment, then influence of genotypes will tend to be greater
- If environment differs greatly across people in a population, then influence of genotypes will be less
Traits are influenced by Genotypes?
- Does not mean that genes influence behaviour directly
- Perhaps genes influence physical or physiological characteristics, which influence behaviour & personality
Selective Breeding?
- Can only occur is a desired trait is heritable
- Selective breeding studies of digs (or other animals)
- Cannot be ethically conducted with humans
- You can think different personality traits of dogs and different breeds (or other animals)
- Dog personality questionnaire
Family Studies?
- Correlates the degree of genetic overlap among family members with the degree of similarity in personality trait
- if a trait is highly heritable
- Family members with greater genetic relatedness should be more similar to one another on the trait than family members who are less closely genetically related
Family studies Limitations?
- Members of a family who share the same genes also usually share the same environment – confounds genetic with environmental influences
- This doesn’t mean people can have different environmental influences within a family
- Thus, family studies are never definitive
Twin Studies?
- Monozygotic (MZ) twins are identical twins
- Dizygotic (DZ) twins are fraternal twins
- MZ share 100% of genes
- DZ share 50% of genes that vary across species
- Same as siblings of same parentage
-If MZ twins are more similar than DZ twins, this provides evidence of heritability - Calculating heritability estimates
- Different ways to do it
Twin Heritability Estimates
- Because MZs share same genes, differences in phenotypes (traits) can only be attributed to “environment”
- Differences between Twin 1 and Twin 2 not due to genes; therefore, due to “environment” - Differences in phenotypes between pairs of DZ twins can be attributed to different genes for different “environment”
- Some of the genes are different between DZ twins
Twin Study Limitations?
- Equal environments assumption: The twin method assumes that the environments experienced by identical twins are no more similar to each other than are the environments experienced by fraternal twins
- General support for this assumption, but it is an ongoing concern with this kind of research
- Representativeness: The experience of twins is not representative of the general population (i.e., generalizability)
Adoption Studies?
- Positive correlations on traits between adopted children and adoptive parents provide evidence of environmental influence
- Positive correlations on traits between adopted children and genetic parents provide evidence of genetic influence
- Adoption studies are powerful because they can disentangle genetics and environment a bit more
- Biological parent and child: are they the same because of genetics or environment?
- Generalizability still a concern
Problem of selective placement of adopted children
Adoption Twin Studies?
- Combine twin & adoption studies
- Mz Twins raised in the same environment (reared together)
- MZ Twins raised in different environments (reared apart) - MZ reared apart unlikely to have same environments as MZ reared together
- Minnesota Study of Twins Reared Apart
- 1979 by Tom Bouchard
- Newer twin studies continue at University of Minnesota today
Sexual Orientation?
- Sexual orientation: refers to one’s sexual and/or emotional attraction to others based on their sex or gender. Identities associated with sexual orientation include gay, lesbian, bisexual, pansexual, asexual, etc
Shared environment?
- in family environment, features of the environment shared by siblings
- E.g., Kids in same family have same SES, go to same schools, share same child rearing
Nonshared environment?
- In family environment, features of the environment that differ across siblings
- E.g., different friends, different teachers, different teachers, different relationship with parents
Genotype-Environment Interaction?
- People with different genotypes can respond differently to the same environments
- Example: Task performance of introverts versus extraverts in loud versus noisy conditions - People with different genotypes exposed to different environments
- Example: How often do you go to parties or not? Extraverts may opt into these environments more often
What are the three types of Genotype-Environment correlation?
- Passive
- Reactive
- Active
Passive
- Parents provide genes and environment, kid does nothing
- ex: Parents choosing number of books in home
Reactive
- Kid behaviour, parents reacts to specific genotype
- Kid likes reading, parents give kid more books or take the kid to the library more often
Active
- kid with particular genotypes seeks out environments
- Kid chooses to spend time in libraries
If personality traits are heritable, how does it work?
- Genetic code influences development of biological structures
- Genetic code influences activity of hormones, neurotransmitters, and other chemical processes within body
Phineas Gage Accident (1848)
- Phineas Gage suffered from a brain injury from a railroad construction accident
- Rod went through his skull, but he survived the accident - Suffered damage to his frontal lobe
- Prior to his accident, he was a highly agreeable and conscious
- After his personality changed dramatically, became obstinate and capricious
Physiological Measures?
- Electrodermal Activity (skin conductance)
- Sweating when presented with certain stimuli - Cardiovascular activity
- Examples: blood pressure & heart rate - Brain Activity
- Examples: EEG, PET, fMRI - Biochemical analyses of blood and saliva
- Hormone levels (e.g., cortisol)
- Neurotransmitter levels
Physiologically-Based Theories of Personality?
- Extraversion & arousal
- Sensitivity to reward and punishment
- Sensation seeking
- Neurotransmitters and personality
- Brain asymmetry and affective style
Eysenck & Extraversion?
- Basic assumption is that the human brain has excitatory and inhibitory neural mechanisms
- Balance between the two produces level of physiological arousal at any given moment
- Neural activity reflects activity of various neurotransmitters
- Dopamine, serotonin, norepinephrine, acetylcholine, etc - Level of arousal fluctuates over course of day
- Arousal can be changed by:
- Environmental factors: music, noise
- Activities: exercise
- Ingested food/chemicals: sugar, caffeine, nicotine
excitatory mechanisms
alert, awake, aroused
Inhibitory mechanisms
sleepy, drowsy, sluggish
Regulation of Arousal
- Balance between excitatory and inhibitory activity is maintained (or regulated) by Ascending Reticular Activating System (ARAS)
If ARAS gateway is typically somewhat closed, baseline level of cortical arousal will generally be relatively low
- Extraverts’ situation
Is ARAS gateway is typically open wide, baseline level of cortical arousal will generally be relatively high
- Introverts’ situation
Finding optimal arousal: Extroverts?
- Extraverts attempt to increase arousal, and perform better when able to increase cortical arousal into pleasant range
- Seek stimulation from environment
Finding Optimal Arousal: Introvert
- Introverts attempt to decrease arousal, and perform better when able to decrease cortical arousal into pleasant range
- Seek to minimize stimulation from the environment
Green’s test of Eysenck’s Theory of Extraversion?
- Extraverts and introverts do Paired-Associates Learning Task with ransom background noise
- “You Decide” condition: ⅓ introverts and ⅓ Extraverts can adjust volume of noise
- Preferred condition: ⅓ introverts assigned to introverts’ noise preference; ⅓ of Extraverts assigned to Extraverts’ noise preference
- Opposite condition: ⅓ Extraverts assigned to introverts’ noise preference; ⅓ introverts assigned to Extraverts’ noise preference
Conclusions of Green Study?
- Introverts and extraverts differ in preferences for background noise
- Extraverts preferred more noise than introverts - Each has moderate arousal and best performance when in preferred noise environment
- Extraverts perform less well when in low arousal (introverts’) environment
Introverts perform less well when in high arousal (extraverts’) environment
Gray’s Reinforcement Sensitivity Theory: Behavioural Activation System (BAS):
- Behavioural Activation System (BAS):
- Responsive to rewards and regulates approach behaviour
- Active BAS produces impulsivity
- Neurotransmitter = dopamine
Gray’s Reinforcement Sensitivity Theory: Behavioural Inhibition System (BIS):
- Behavioural Inhibition System (BIS):
- Responsive to punishment, frustration, uncertainty, and motivates ceasing, inhibiting, or avoidance behaviour
- Active BIS produces anxiety
- Neurotransmitter = serotonin
Avoidance System (Behavioural Activation System)
- Both Approach & Avoidance based in Limbic System
- For approach system (BAS)
- In particular, the septal nuclei & nucleus accumbens - Causes one to be sensitive to potential rewards & motivates reward seeking behaviour
- When BAS active, one craves rewards (impulsive)
- When BAS inactive, one is unmotivated
Inhibitory System (Behavioural inhibitoy system):
- Based in hippocampus, although this region is mostly associated with memory, not just emotion
- Amygdala, in the limbic system, is also key (vigilance response to info) - Sensitive to potential punishments & motivated to avoid them
- When active, person is anxious
Individual Differences in BIS & BAS?
- Individuals differ in threshold for activating BAS (Activation system) and BIS (inhibition system)
- Some people more sensitive to reward than others
- E.g., first day at new school (anticipation or ho hum?)
- Some people more sensitive to punishment than others
- E.g., final exam (anxious or calm?)
Assessing BIS & BAS in Humans: BIS (inhibition):
- Even if something bad is about to happen to me, I rarely experience fear or nervousness. (R )
- Criticism or scolding hurts me quite a bit
- If I think something unpleasant is going to happen I usually get pretty “worked up”.
- I have very few fears compared to my friends. (R )
Assessing BIS & BAS in Humans: BAS (Approach):
- I go out of my way to get things I want
- I’m always willing to try something new if I think it will be fun
- When I’m doing well at something, I love to keep at it
- I will often do things for no other reason than that they might be fun
BIS & BAS: Daily Experience: High BIS sensitive
- Experienced more negative emotions
- More affected by negative events
BIS & BAS: Daily Experience: High BAS Sensitive
- Experienced more positive emotions
- Experienced more positive events
BIS & BAS Depression
- Kasch et al. (2002)
- People high in depression have higher BIS sensitivity and lower BAS sensitivity vs. people not depressed
- People high in depression with lower BAS sensitivity showed less recovery 8 months later
Updating Reinforcement Sensitivity Theory: BAS reward sensitivity (similar to extraversion)
- Motivation to approach potential rewards, impulsivity
Updating Reinforcement Sensitivity Theory: BIS Conflict sensitive (similar to neuroticism, anxiety)
- Sensitive to uncertainty, choice dilemmas, novelty
- No longer focus on punishment - more internal conflict
Updating Reinforcement Sensitivity Theory: FFFs (Fight, flight, freeze system): Sensitive to danger
- Demands immediate response
-Response to punishment to threat - Panic and fear
Sensation Seeking?
- Tendency to seek out thrilling, exciting activities, take risks, avoid boredom
Monoamine Oxidase (MAO)
- Enzyme that maintains neurotransmitter levels
- High sensation seekers have low levels of MAO
Dopamine
- Associated with pleasure
- Animals motivated to receive dopamine much like food rewards
- Several drugs (e.g., Cocaine) mimic dopamine, but reduce natural production
- related to extraversion
- Also related to Openness in some recent research (in a different way - salience of information)
Serotonin
- Low levels associated with depression and anxiety
- Common anti-depression prevent the reuptake of serotonin, making more serotonin available in the synapse for better transmission between neurons
- Related to neuroticism
Biological systems and processes are complicated?
Correlations between traits and absolute levels of a neurotransmitter can’t give you the full story
Dopamine and Extraversion?
- Researchers have explored the number of dopaminergic neurons, and response to increasing dopamine with drugs
- The reaction to dopamine differs, not baseline levels
Serotonin & Neuroticism?
- Anti-depressants (SSRIs, specifically) try to reduce reuptake, but don’t work for everyone
- Some animal studies show direct increases in serotonin in hippocampus increases anxiety
- Might be due to different facets of neuroticism
Brain Asymmetry and Affective Style?
- Left and right sides of the brain are specialized, with asymmetry in control of psychological functions
- An EEG, can measure brain waves, such as alpha wave - an inverse indicator of brain activity
- Alpha waves oscillate at 8-12 times and second
- Less alpha wave is present, more the brain is active
EEG Readings?
- Higher activity in left frontal hemisphere = positive mood
- Higher activity in right frontal hemisphere = negative mood
Stable Asymmetry?
- Asymmetry (left over right and right or left) is a stable individual difference
- Some people have relatively more activation in right frontal hemisphere
- Respond more to anxiety-producing stimuli - Other people have relatively more activation in left frontal hemisphere
- Respond more to appealing stimuli
PA (Postive Affectivity)
- A tendency to experience more positive emotions (joy, vigour, alert, excited)
NA (Negative Affectivity)
- A tendency ti experience more negative emotions (Afraid, anxious, irritable, distressed)
What is Evolutionary Theory?
- Argues that distinctive features of human nature (physical and psychological) have developed by small increments over many generations because of the selective advantage they gave our ancestors
- I.e., those who had adaptive solutions to recurrent problems faced by the species were more likely to survive and reproduce successfully
What are the processes by which evolutionary adaption occurs?
- Natural Selection
- Sexual Selection
Theory of Natural Selection?
- Members of the species must differ on some characteristic (i.e., variants or variation)
- Some of these variations must be to some significant degree heritable (i.e., genetic)
- Organisms with “successful variants” leave more offspring because those attributes helps with the tasks of survival or reproduction
- Assumes hostile forced of nature
“Hostile forces of nature”
- Any event that impedes survival
- Example: food shortages, diseases, parasites, predators, & extreme weather - “As more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life”
Natural Selection
- Natural selection is a process that helped our ancestors to survive challenges in the African savannahs ~200,000 yrs ago
- evolution is a slow process
Arousal?
- Limbic system: detects & interprets threatening stimuli
- The middle ground of arousal (not too low or too high) was most adaptive
Too high or too low was literally a matter of life and death (and ultimately, species survival)
Sexual selection?
- Passing on genes requires reproduction
- Those who don’t mate do not pass on genes
- Some heritable characteristics give selective mating benefits to those who possess them
- Peacock’s tail
- Stag large antlers
- Facial symmetry in humans
Intrasexual competition
- Members of same sex compete for mating access
- Example: Two stags locking horns in combat
Intersexual competition
- One sex chooses mate based on their preference for particular qualities
- If members of one sex have some consensus about qualities that are desirable, the individuals of opposite sex possessing those qualities will be preferentially chosen as mates