Personality_Biological Domain Flashcards
Human Nature
- The product of evolutionary process
- Help human beings survival and maintain species
Examples of Evolutionary Analysis in the Level of Human Nature
- The Need to Belong
- Helping and Altruism
- We help individuals who have more related genes to ours
- E.g. relatives, siblings - Universal Emotions
Sex Differences
Psychologists believe that if male and female had the same or similar adaptive problems, male and female would be the same or similar
Examples of sex differences due to
confronting with different adaptive
problems
- Aggression
- Jealousy
- Desire for Sexual Variety
- Mate Preferences
Genome
- Total genes that organisms occupy
- Comprises 30,000–80,000 genes on 23 pairs of chromosomes
- Most genes are the same in every human beings
- Some genes are different in each human beings
- E.g genes for physical appearances, personality
Human Genome Project
To find the sequence of human DNA molecules
Behavioral geneticists try to…
Specify how much proportion of heredity and environment contributes to personality differences
Debated Issues in Human Genome
- Ideological concerns
- Eugenics
Heritability
The proportion of observable variances/differences (phenotype) that could be explained by genetic variances/differences (genotype)
- CANNOT be applied to single individual
- Is NOT constant or immutable
- Is NOT a precise statistic
Environmentality
species’ observable variances that could be explained by environment
Behavioral Genetics Methods
- Selective Breeding—Studies of Humans’ Best Friend
- Family Studies
- Twin Studies
- Adoption Studies
Selective Breeding
- Can only occur if a desired trait is heritable
- Selective breeding studies of dogs
- Cannot be ethically conducted with humans
Family Studies
- Find the correlations of family genes and personality traits
- “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.”
Problem of Family Studies
Members of a family who share the same genes also usually share the same environment— confounds genetic with environmental influences.
- Thus, family studies are never definitive
Twin Studies
Estimates heritability by gauging whether
- Identical (monozygotic or MZ) twins, who share 100 percent
of genes, are more similar than
- Fraternal (dizygotic or DZ) twins, who share only 50 percent of genes
Evidence of Heritability
MZ twins are more similar than DZ twins
Calculating Heritability
There are many formulas
2 (rmz – rdz)
- Two times difference between correlation (“r”) for MZ twins and DZ twins
Two assumptions of the twins method
- Equal environments assumption
- Representativeness assumption
Representativeness Assumption
- Twins are representative of the general population for a given trait of interest
- Thus, this assumption holds that twins do not have different rates of psychopathology compared with non-twin (i.e., singleton) individuals
Adoption Studies
- Positive correlations on traits between adopted children and ADOPTIVE PARENTS provide evidence of environmental influence
- Positive correlations between adopted children and GENETIC PARENTS provide evidence of genetic influence
Pro of Adoption Studies
Equal environmental assumption
Con of Adoption Studies
- Assumption that adopted children and their adoptive and genetic parents are representative of the general population is questionable
- Selective placement of adopted children
Twins Reared Apart
- Design that combines strengths of twin and adoption studies
Behavioral Genetic Research
- Personality Traits
- Attitudes and Preferences
- Drinking and Smoking
Personality Traits
- Traits come from genes 20-45%
- Big 5
Sexual Orientation
- Still being debated
- Genes have moderate influence to childhood gender nonconformity (moderator) and to adult sexual orientation
- Physiological influences of sexual orientation
Attitudes and Preferences
Wide variance in heritability of attitudes
- Some attitudes (e.g., traditionalism) show high heritability (about .60)
- Whereas others show low or no heritability (e.g., beliefs in God)
- Still unclear why some attitudes have genetic influences
Drinking and Smoking
- Related to traits e.g., sensation seeking, extraversion, neuroticism
- Drinking alcohol and smoking cigarettes are stable for a long time shows genetic-related
Genes and the Environment: 2-Issued Consideration
- Genotype-Environment Interaction
- Genotype-Environment Correlation
Genotype-Environment Interaction
- DIFFERENT RESPONSE to the same environment due to different genes
- E.g., Performance of introverts vs. extraverts in noisy environment
Genotype-Environment Correlation
Different genetic individuals have DIFFERENT APPROACH to deal with stimuli/environment
3 Types of Genotype-Environment Correlation
- Passive
- Reactive
- Active
Genotype-Environment Correlation: Passive
Parents set genes and environment for their children
- E.g. Language ability and the numbers of the books in the house
Genotype-Environment Correlation: Reactive
Different REACTIONS from parents or others due to children’s different genes or traits
- E.g., if the child is cute, others will pamper/love them
Genotype-Environment Correlation: Active
Individuals who have some genes will SEEK the specific environments
- E.g. High sensation seekers will seek or search for the risky environments
Molecular Genetics
Technique to find the relatedness of genes and traits
Example of Molecular Genetics
E.g. D4DR gene located on the short arm of chromosome 11, codes
for dopamine receptor
- Find the correlations between
D4DR gene and “novelty seeking” trait.
- “Long repeat” D4DR -> higher novelty seeking
- “Short repeat” D4DR -> lower novelty seeking
* Some research found no correlations or low correlations
Physiological Technique to Study Personality
- Electrodermal Activity; Skin Conductance
- Cardiovascular activity
- Brain Activity
- Biochemical analyses of blood and saliva
Electrodermal Activity (EDA): Skin Conductance
Electrode or sensor attached to the skin
- Pro: Noninvasive, no discomfort
- Con: Movement constrained
- Electrodermal activity—sweating or skin conductance when there are emotional triggers
Cardiovascular Activity
- Blood pressure e.g. stress reactivity
- Heart rate increased while anxiety, fear, arousal, cognitive effort
- Cardiac reactivity—when doing activity e.g. backward serial subtraction
- Related to Type A personality impatience, competitiveness, hostility
- Cardiac reactivity and Type A related to coronary heart disease
Brain Activity
- Brain produces small amounts of electrical activity
- Measured by electrodes on scalp electroencephalograph (EEG)
- Evoked potential technique: EEG + stimulus -> assess specific brain response to stimulus
Brain Imaging Techniques
Map structure and function of brain
- Positron emission tomography (PET)
- Functional magnetic resonance imaging (fMRI)
Physiologically Based Theories of Personality
- Extraversion-Introversion
- Sensitivity to Reward and Punishment
- Sensation Seeking
- Neurotransmitters and Personality
- Morningness-Eveningness
- Brain Asymmetry and Affective Style
Extraversion-Introversion
- Introverts has higher activity of ascending reticular activating system (ARAS)
- Individuals try to maintain ARAS activity at optimal level
- Introverts reduce arousal
- Extraverts seek arousal
Sensitivity to Reward & Punishment
BIS/BAS
Behavioral Activation System (BAS)
- Responsive to incentives (cues to reward)
- Regulates approach behavior
- Active BAS produces impulsivity
Behavioral Inhibition System (BIS)
- Responsive to cues to punishment, frustration, uncertainty
- Motivates ceasing, inhibiting, or avoidance behavior
- Active BIS produces anxiety,
Impulsive
- High extraversion,
- Moderate neuroticism
Anxious
- Moderate introversion
- High neuroticism
- Do not learn well from punishment because of weak BIS
- Learn better from reward
Sensation Seeking
Tendency to seek out thrilling, exciting activities, take risks, avoid boredom
Sensation Seeking: Early Sensory Deprivation Research
- High sensation seekers are less tolerant of sensory deprivation
- Require much stimulation to get
to optimal level of arousal - Positive correlation between extraversion and sensation seeking
Physiological Basis for Sensation Seeking
Monoamine Oxidase (MAO)
- Enzyme that maintains a proper level of neurotransmitters
- Low MAO ->
- High sensation seeking ->
- Producing a need for stimulation to reach the optimal level of arousal
Dopamine
Pleasure
Serotonin
- Depression
- Other mood disorders
Norepinepherine
Fight or flight response
Cloninger’s Tridimensional
Personality Model
- Novelty seeking: low levels of dopamine
- Harm avoidance: low levels of serotonin
- Reward dependence: low levels of norephinepherine
Morning Person
Shorter circadian rhythms
Evening Person
Longer circadian rhythms
Brain Asymmetry and Affective Style
- Dispositionally positive
- Dispositionally negative
