PSYC 2740 Chapter 6: PSYC 2470 Chapter 6
6 Jul 2018
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PSYC 2470: Personality Psychology
Chapter 6: Genetics and Personality
The Human Genome
Genome: complete set of genes in an organism
Human Genome Project
oThe manner in which human genes get decoded into proteins turns out to be far more than in
other species
oGenetic junk: functionless residues that serve no purposes
Controversy About Genes and Personality
Eugenics: we can design the future of the human species by fostering reproduction of people with
certain traits and by discouraging the reproduction of people without those traits
Goals of Behavioural Genetics
Percentage of variance: individuals vary from one another and this variability can be put into
percentages that are due to different causes
Ways in which genes and the environment interact and correlate with one another
What is Heritability?
Heritability: proportion of observed variance in a group of individuals that can be accounted for by
genetic variance
oDegree to which genetic differences cause differences in observed property
Formal definition
oThe proportion of phenotypic variance that is attributable to genotype variance
Phenotypic variance: observed individual differences such as height, weight or personality
Genotypic variance: individual differences in the total collection of genes possessed by each person
Environmentality: the percentage of observed variance in a group of individuals that can be contributed
to environmental (non-genetic) differences
Misconceptions About Heritability
It cannot be applied to single individuals
It is not constant
Not a precise statistic
Nature Nurture Debate Clarified
Nature-nurture debate: whether genes or environment are more important determinants of personality
oLevel of individual
Each person has unique genes
Environment influences genes to make up an individual
oLevel of a population of individuals
Behavioural geneticists
Differences in genes and differences in environments
For a particular population at a given point in time, we can make sensible statements
about which is more important in accounting for the differences
Behavioural Genetic Methods
Selective Breeding: Studies of Human's Best Friend
Selective breeding: identifying dogs that possess the desired characteristics and having them mate with
only other dogs that also have the desired characteristic
Document Summary
Genome: complete set of genes in an organism. Human genome project: the manner in which human genes get decoded into proteins turns out to be far more than in other species, genetic junk: functionless residues that serve no purposes. Eugenics: we can design the future of the human species by fostering reproduction of people with certain traits and by discouraging the reproduction of people without those traits. Percentage of variance: individuals vary from one another and this variability can be put into percentages that are due to different causes. Ways in which genes and the environment interact and correlate with one another. Heritability: proportion of observed variance in a group of individuals that can be accounted for by genetic variance: degree to which genetic differences cause differences in observed property. Formal definition: the proportion of phenotypic variance that is attributable to genotype variance. Phenotypic variance: observed individual differences such as height, weight or personality.
