CHAPTER 3 : BIOLOGICAL APPROACH (adam)
Heritability is the proportion of phenotypic variance that is attributable to genotype variance
Phenotypic - observed individual differences such as height,weight and personality
Genotypic - individual differences in the total collection of genes possessed by each person
Misconception about Heritability
can be applied to a single individual
that it is constant
is an absolutely precise statistic
Nature and Nurture debate
Level of Individual - no nature-nurture debate
Level of a population of individual - Genetic influence are more important than environmental difference for height
Behavioural Genetic Methods
Selective Breeding - possessed characteristic breed same characteristics resulting in desired characteristics.
Family Studies
known degree of genetic relatedness among family members
Each parent shares 50% of their genes whereas grandparent and grandchildren shares only 25%
Family members who share same genes = share the same environment
Twin Studies
shared many behavioural habits
Also share many personality traits such as highly conscientious and emotionally stable
Adoption Studies
Can examine the correlation between adopted children and their adoptive parents, whom they share no genes
Also adopted children and their genetic parents
no influence on the children's environment
environment strongly influences the personality trait
Genes and Environment
Genotype-Environment Interaction
Genotype-Environment Correlation
Differential response of the individuals with different genotype
Example - Introverts and Extroverts
Differential exposure of individuals with different genotype to their different environments
Passive genotype environment - parents provide both genes and the environment to the children
Reactive genotype environment - parents responds to the children differently
Active genotype environment - person with particular genotype seeks out a particular environment
Physiological Approaches to Personality
Neurotransmitter and Personality
1 neurotransmitter and 1 dopamine appears to be associated with pleasure
Neurotransmitter like Serotonin are associated with depression and other mood disorder
Norepinephrine is involve in activating sympathetic nervous system
Circadian Rhythims
Morning person - Stable characteristics
Night person - unstable , moody characteristics
Short biological rhythms - hits their peak body temperature and alertness earlyand thus began to get sleepy earlier