week 5 nature vs nurture Flashcards
what are the 3 poles of possibility in the triangle of destiny
free will, genes, environment
which 2 aspects of the triangle of destiny are deterministic
genes and environment
what is the example of graham young?
“the teacup poisoner”
poisoned family members as a teenager and one died, he was convicted and sent to prison. was released after 9 years as said he was “fully recovered”. then killed 2 co-workers and was sent back to prison and died himself
what were graham young’s traits from the big 5?
low extraversion
low neuroticism
high conscientiousness
low openness
very low agreeableness
very low honesty-humility
what is the source of biological variation between people
mutations
heredity
the passing on of phenotype characteristics to offspring
inheritance
the biological mechanism of heredity
all genes are inherited but not all phenotype characteristics are
how can the environment be biological
the womb as a child, and nutrition as an organism
shared environment
those characteristics that are common to the environment of different people, usually overlapping family environment of kids eg parental income
non-shared environment
those characteristics that are unique to the environment of different people, usually distinctive social environment of kids eg special parental treatment
what’s the formula for phenotype
VAR(Phenotype) = VAR(Genotype) + VAR(Environment)
VAR(P) = VAR(G)+ VAR(E)
Plus 2 x COVAR(G, E)
what’s the formula for heritability
Heritability = VAR(G) / VAR(G) + VAR(E)
Heritability = VAR(G) / VAR(P)
heritability = H2
what’s the formula for non-heritability
Non-heritability = VAR(E) / VAR(G) + VAR(E)
Non-heritability = VAR(E) / VAR(P)
Non-heritability = 100 - H2
Non-heritability = VAR(E) contribution to VAR(P)
What is a heritability example where genes win?
eye color - follows simple mendelian inheritance
what is a heritability example where the environment wins?
language and accent
what are the 3 genetic variance types?
- additive = VAR(GA)
- genes have independent effects on phenotype - dominant VAR(GD)
-some genes tell others what to do at the same locus - epistatic VAR(GE)
- some genes tell others what to do, at different loci
what’s the formula for overall genetic variation?
VAR(G) = VAR(GA) + VAR(GD) + VAR(GE)
For many analyses, one can just assume that VAR(GA)
predominates, and ignore VAR(GD) and VAR(GE)
what are the 3 types of combinations of heritability?
- aggregation (G+E)
- effects of nature&nurture vary in inverse proportion
-main type of combo - interaction (GxE)
- effect of nature depends on nurture, vice versa
-diathesis stress model - influence (G<>E)
- effect of nature operates via nurture or vice versa
what is the epigenetic phenomenon?
sometimes the environment can switch gene expression on or off
done by methylation or demethylation of DNA
drugs or stress affect this
give one example of influence heritability using university
- genes make one smart
- being smart, so goes to uni (choice of environment)
- going to uni makes me smarter
(environmental effect on intelligence phenotype)
give the cycle of violence example
- abusive parents abuse their children
- the children now become abusive and abuse their own children
- cycle continuous
what are 2 ways to separate environment and genotypic variance?
- hold genotype constant, let environment vary and observe variation in phenotype
- hold environment constant, let genotype vary and observe variation in phenotype
what are the 2 main study methods to study behavior genetics
- twin studies (removes genetic differences)
- adoption studies (removes biological parent environment and adoptive parent genes)
monozygotic
share 100% DNA
reared together twin studies
environmentally similar
reared apart twin studies
environmentally different
falconers formula
Heritability = 2 x (MZ-DZ)
Unique Env. = 1 – MZ
Shared Env. = DZ - (H/2)
equalizing the environment increases the…?
heritability
more equal societies have larger…?
gender differences
