Exam 2 - PSY 3250

What do personality researchers ask in relation to genes and environment?

How do genes and environment contribute to individual differences in personality?

Percentage of variance

Refers to the fact that individuals differ from one another and that variability can be divided into the portion that is due to cause X (genes) and the potion that is due to cause Y (environment)

What are the 3 main goals of behavioral genetics research?

1. Find out the percentage of variance attributable to genes and percentage attributable to environment

2. Figure out how genes and environment interact

3. Figure out exactly where in the environment the effects are coming from

Nature vs. Nurture

More like nature via nurture, it’s not a debate of which one causes the behavior so much so that it is a discussion on how both simultaneously impact a behavior. Genes and environment need each other, genes are incapable of building anything without environmental input and vice versa.

What does it mean to say IQ is 60% genetic and 40% environment?

60% of the difference btw ppl in IQ are due to differences in their genes and 40% of the differences in their IQ are due to differences in their environment

The key idea: breaking down an outcome into % due to genes and % due to environment only makes sense when you’re talking about differences btw ppl.

Population level of explanation

Difference between people, we can successfully break a trait down into % due to genes and % due to environment

Individual level of explanation

Talking about a single person, it’s impossible to assign %’s

What are the 4 methods of studying behavioral genetics?

1. Selective breeding of nonhuman animals

2. Family studies

3. Twin studies

4. Adoption studies

What is artificial selection?

When humans breed certain traits into or out of a species

Heritability

The proportion of individual differences in a trait that are due to genetics

How are family studies used?

It makes use of the different degrees of genetic relatedness between families

What is the logic of family studies?

If a trait is highly heritable family members who are genetically closer will be more alike in that trait. If the trait isn’t heritable they won’t be.
The issue is family members who share the same genes tend to shared the same environment

What is the logic of twin studies?

If identical twins are much more alike in a trait than fraternal twins that trait is highly heritable (genetics is important)
If identical twins are not more alike in a trait than fraternal twins, that trait is not heritable at all (genetics not important)

What is the formula for heritability

2(r_mz - r_dz)

What is the logic of adoption studies?

Examine the correlations between adopted children and their adoptive parents

If the correlation is high → strong evidence of environmental influence

What is the most powerful type of study?

Twin Adoption Studies (especially identical twins)

What is a Twin Adoption Study?

Twins reared apart in adoptive families

Combines strengths of adoption and twin studies, rare but powerful.

Clear results: you can interpret the correlation between identical twins reared apart on a certain trait as a direct measure of the heritability for that trait

What is a major finding from a twin study?

Many personality traits are moderately heritable (about 40-70%)

Shared environment

Parents, parents’ attitudes & values, books and movies in the house, quantity & quality of food in house, neighborhood

Non-Shared Environment

Unique features, different groups of friends, different teachers in school, different books and movies

What is a shocking finding in the last 40 years?

For most traits, shared environment has little to no effect. Almost all environmental effects are due to the non-shared environment.

This implies parental attitudes & behaviors have little effect

What 3 things drive our individual differences in personality and other traits?

1. Genes

2. Non-shared Environment

3. Chance

Key Conclusions

1. Most traits: moderate to high heritability (40-70%)

2. Most traits: moderate non-shared environmental effects (30-60%)

3. Most traits show surprisingly small effects of shared environments (with some exceptions like IQ and religion)

4. These conclusions are equally true for physical traits and psychological traits

5. Gene x Environmental interaction + Gene-Environment + Correlation complication the picture further

Gene-Environment Interaction

The effect of the environment DEPENDS on which genes you have.

Example:
Due to having genes for low levels of the neurotransmitter monoamine Oxidase A, kids who are faced with abusive parenting are more likely to have an antisocial personality. The effect of abusive parenting depends on the kids genes specifically the levels of MAO-A

Gene-Environment Correlation

A person’s genes can affect what environment they get exposed to

Example:

A kid has a genetic disposition for mathematical ability. Her parents notice this and therefore supply her with lots of math books, games, and puzzles.

What are the three kinds of gene-environment correlation?

1. Passive

2. Reactive

3. Active

Passive Gene-Environment Correlation

The child inherits both genes and environmental exposure from the parents

Example:
Intellectual parents provide both 1) genes for intellect and 2) a house full of books

Reactive Gene-Environment Correlation

The child inherits genes from the parents → this leads to a certain ability → parents notice this ability and then tailor the environment they provide accordingly

Active Gene-Environment Correlation

The child inherits genes from the parents, leading to a certain ability. The child then actively seeks out environments that correspond to that ability and develop it further

What do physiological approaches to personality attempt to understanding personality in terms off?

• Brain

• Nervous System

• Endocrine Systems (hormones)

Commonly used physiological measures

• Electrodermal Activity (skin conductance)

• Cardiovascular Activity

• Brain Activity

• Hormones

Electrodermal Activity (EDA): Skin Conductance

The logic of skin conductance:

• Hands and feet: high concentration of sweat glands

• These sweat glands activated by SNS

• Sweat conducts electricity

• So we can directly measure SNS activity by measuring how well the hands conduct electricity

Cardiovascular and Brain Activity

• BP and HR

  • Measure of stress reactivity

  • HR also increases w/cognitive effort

  • Those who are more stress-reactive and show more cardiac activity, are at higher risk of heart disease

• Brain Activity

  • EEG → different electrical patterns

  • fMRI → brain response

  • MRI → reliable difference in brain structure

Other physiological measures

• Immune Function

• Hormones

Introverts

Have a higher level of activity in the brain’s ascending reticular activating system.

Work to decrease stimulation based on Eysneck’s theory

What does ARAS do?

Thought to control overall cortical arousal, people strive to keep the ARAS activity at optimal level

Extraverts

Work to increase stimulation based on Eysneck’s theory

What is the difference between I and E?

Research found no baseline differences between the two. Instead there was a difference in response to stimulation: I’s respond faster and more strongly to stimulation, are overly aroused under extraverted conditions whereas E’s overly bored under introverted conditions. I’s and E’s prefer their own conditions

Neuroscience of Extraversion

Most commonly linked with brain systems that govern positive emotion and sensitivity to reward. Dopamine is a key player. Positive relation btw E and the volume of mOFC (coding value of rewards). Testosterone positively associated with E.

What are specific brain areas involved with extraversion?

• Medical orbitofrontal cortex

• Nucleus accumbens

• Striatum

Neuroscience of Neuroticism

Reflects sensitivity to threat and punishment

Associated w/negative brain areas at rest and brain activity in response to aversive stimuli

Associated w/reduced mPFC volume (relevant to emotion regulation)

Low levels of serotonin

Linked w/higher baseline level of cortisol and also = reduced cortisol increase in response to specific stressors because chronically stressed and less able to mobilize stress response when needed

Greater right frontal lobe activation relative to left because the right is associated with avoidance and withdrawal. The left is associated with approach.

Neuroscience of Agreeableness

The brain systems hypothesized to be important here are those involved in social information processing.

• Medial Prefrontal Cortex

• Superior temporal sulcus

• Temporal-parietal junction

• Mirror neuron system

• Posterior cingulate cortex

• Fusiform gyrus

Higher serotonin = high A

High Testosterone = low A

Brain regions that underly this trait focus on helping others, figuring out how others feel, and being pro social towards others.

Neuroscience of Conscientiousness

Associated with greater volume of the middle frontal gyrus in lateral prefrontal cortex

Neuroscience of openness

Potential region of interest: dorsolateral prefrontal cortex.
Dopamine
Composed of openness and intellect which captures a set of traits associated with intelligence, creativity, and cognitive flexibility

Neuroscience of Extreme Altruism

Neuroimaging studies confirm that people like this attach more weight to others’ welfare, processing this in regions such as amygdala and rostral anterior cingulate cortex. Not necessarily a suppression of selfish impulses so much so that it is attaching more weight to others’ welfare

What three things do extreme altruists show?

1. Increased accuracy for distress cues such as fearful faces

2. Increased amygdala activation in response to other people’s fear

3. When watching videos of a stranger being subjected to pain, increased empathic neural simulation (for others’ pain and fear) in anterior insula and anterior cingulate cortex

What is sensation seeking?

The tendency to seek out thrilling, exciting activities, take risks, avoid boredom

What is Hebb’s theory of optimal level of arousal?

People have an optimal level of physiological arousal
If beneath it, they seek to increase
If above it, they seek to reduce

What did Zuckerman notice?

Some people are much less tolerant of sensory deprivation and started to think of these people as sensation seekers

What do genetic studies suggest about impulsivity and sensation seeking?

Certain genes underlie these personality traits. There is a genetic basis for these traits.

What are impulsivity and sensation seeking responsible for?

The comorbidity of problem gambling and other addictions

What is the right frontal lobe responsible for in terms of emotions?

Negative emotions

What is the left frontal lobe responsible for in terms of emotions?

Positive emotions

Are individual differences in frontal lobe stable?

Yes

What activity affects brain asymmetry?

Meditation

What does meditation do to the brain?

Shifts brain to left, leads to less stress, more energy, more engagement at work, and less anxiety, improves immune function

What two tasks did ancestors accomplish?

1. They survived to reproductive age

2. They reproduced

What three steps combined make up natural selection?

1. Variations

2. Inheritance

3. Differential reproductive success

What did Darwin contribute?

How evolution works because we already suspected species evolved.

What are the two purposes of traits?

Some facilitate survival: natural selection
Some facilitate mating success: sexual selection

What are physiological mechanisms and psychological mechanisms?

Traits like immune defense, fight or flight, disgust toward pathogens, fear of spiders and snakes, desire for sweet and fatty foods that helped our ancestors survive and reproduce

What are the two types of sexual selection?

Intrasexual and Intersexual

What is intrasexual selection?

Within a sex, usually males.
Traits that evolve to help organisms compete against rivals for mates like horns and antlers.

What is intersexual selection?

Between sexes.
Traits that evolved because the opposite sex has a preference for them like a peacock’s tail or colorful plumage in birds.

What three products does evolution lead to?

1. Adaptations

2. Byproducts

3. Noise (random variation)

What are adaptations?

Inherited solutions to survival and reproductive problems.
Solve an adaptive problem which is any recurrent problem faced by your ancestors that affected their survival or reproductive success
Example: Umbilical Cord

What are byproducts?

A side effect of adaptations or intrinsically coupled with adaptions that do not solve adaptive problems or contribute to the survival or reproductive success
Example: belly button, redness of blood

What is noise?

Random variation in the features of an adaptation or a byproduct. Can be caused by genes (mutation) or the environment. Often don’t affect the functioning of the organism but can in principal be harmful or beneficial. Does not solve any adaptation problem.
Example: bellybutton size and shape, innie vs. outie

What are the 3 key evolutionary principles?

1. The importance of Function

2. Gene-Environment interactionism

3. Learning and evolution are not competing explanations

3 stages of gene-environment interactionism

1. The original evolution of the mechanism (shaped by environmental pressure

2. The development of the mechanism during a person’s life (environmental input required for proper development)

3. The activation of the mechanism in the immediate present (environment is what triggers the mechanism in the here and now)

The need to belong

Part of human nature, one of the most fundamental human needs

Social Anxiety

Hypothesized to be an evolved psychological mechanism for preventing social exclusion, ensuring that you don’t get ostracized

Evidence of the need to belong

1. External threats increase group cohesion

2. The opportunity to acquire resources increases group cohesion

3. Across cultures, people who spend more time w/others have higher self-esteem

4. Neuroscience and linguistics

5. Being left out or ignored causes intense psychological pain

When will males and females be similar?

Similar in areas where they faced similar adaptive problems

When will males and females be different?

Different in areas where they recurrently faced different adaptive problems

The Embryo Protection Hypothesis

Pregnancy sickness is an evolved defense to protect the fetus by preventing the mother from ingesting teratogens

What is the evidence for the embryo hypothesis?

1. Pregnancy aversion to foods with higher bacterial load

2. Pregnancy sickness is highest during period of sensitive organ development

3. Declines when sensitive organ development declines

4. Olfactory acuity goes up during pregnancy

5. Those with no pregnancy sickness on average are 3x as likely to have a miscarriage

Jealousy

An emotion that evolved to protect one’s relationship and defend it against real or imagine threats

Paternity Uncertainty

Mama’s baby, Papa’s maybe
Mammals have gestation and fertilization internally in a female which means its 100% guaranteed that mom is the mom of the baby but it’s not guaranteed that dad is the dad.

What happens if a male’s long term mate cheated on him?

Directly effects reproductive success

What hypothesis does jealousy lead to?

Men will be more bothered than woman by their mates sexual infidelity whereas women will be more bothered than men by their mate’s emotional infidelity.

What causes females to be more choosier with their mates? (Parental Investment Theory)

Asymmetry in parental investment which means that the minimum obligatory investment for a female is higher than a male. It’s more metabolically expensive for females, potentially dangerous for females, and suppresses ovulation.

What is the evidence for sex differences?

1. Studies on # of partners desired

2. Time elapsed before seeking intercourse

3. Lower of standards in short term mates

4. The closing time phenomenon

5. Sexual fantasies and sex drive

6. Sexual regret

When do men experience sexual regret?

Due to acts of omission

When do women experience regret?

Due to acts of commission

What are the three paths for Individual Differences?

1. Environmental Triggers

2. Reactive Heritability

3. Frequency-Dependent Selection

Effect Size

A measure of the magnitude of an effect (Cohen’s d)

Sex and Gender Differences in Children’s Temperament?

• Higher inhibitory control and perceptual sensitivity in females

• Higher surgency and physical aggression8 in males

• No diff/ in negative affectivity

Proximate

How

Ultimate

Why

People-Things Dimension

Men more thing oriented (carpenters, engineers, mechanics tool makers)
Women more people oriented (nurses, teachers, social workers, counselors, care providers)

Sex and Gender Differences in Depression

After puberty women 2-3x higher for rates of depression however they are also more likely to seek treatment, think more about it, more nervous activity and more likely to attempt unaliving however men are more likely to actually die from their unaliving attempts. Men are also more inactive, withdrawn, use drugs, and get aggressive.

What are the 3 components of gender stereotypes?

1. Cognitive → forming social categories in mind

2. Affective → feeling a certain way about the categories formed

3. Behavioral → treating ppl diff. based on those categories

What are the sub-stereotypes of men?

• Social climber career man

• Playboy/player/ladies man

• Confident intellectual type

• Sensitive quiet type

What are the sub-stereotypes of women?

• Liberated independent career woman

• Classically feminine good mother housekeeper

• Sexy flirtatious promiscuous

Theories of Sex and Gender Diff.

• Socialization Theory

• Hormonal/Physiological Theories

• Evolutionary Psychological Theory

• An Integrated Theoretical Perspective

Socialization Theory

Suggests that boys and girls become different because boys are reinforced by parents, teachers, and media for being “masculine” and girls for being “feminine”.

Two issues:

1. Direction of causal arrow is unclear → parents may treat kids diff. bcos of naturally occurring sex diffs. not the other way around

2. Does not explain the origin of sex-differentiated socialization practices

Hormonal and Physiological Theories

Hormonal and physiological differences cause boys and girls to diverge over the course of development. Men and women primarily because of differences in their hormones and physiology. Still doesn’t explain origins of hormonal differences and is also bidirectional because behavior can affect hormones just as much as hormones affect behavior.

Evolutionary Psychological Theory

• Men and women are predicted to differ in those domains in which they recurrently faced different adaptive problems and will be similar in those domains in which they faced the same/similar adaptive problems.

• Only one that explains origins of sex differences and only one that actually predicts sec differences/similarities in advance

Integrated Theoretical Perspective

Evolutionary theories specific why(ultimate) and in what areas the sexes will be different or similar but not how these differences arise.
Hormonal and socialization theories specify how(ultimate) the differences might arise but not why they exist in the first place.