Cog & Bio Behavioural Genetics Flashcards
(26 cards)
What is behavioural genetics the study of?
How genes and the environment influence behaviour - approach that looks at the nature nurture debate
It’s an interdisciplinary field that combines what?
Psychology, biology and statistics
What is behavioural genetics interested in?
Explaining behaviour based on genetics - but we all share >99.5% DNA
Each cell has what?
A nucleus with chromosomes inside, and inside these chromosomes are genes = DNA
What can a gene code for?
Can code for more than one behaviour - hard to get to grips of genetic components of behaviour
Genetically, humans are very similar
What animal shows greater genetic diversity?
Chimpanzee
Have much more variance in DNA than humans - less homogeneous
How do people look alike who aren’t related?
They have similar genetic coding
What does behavioural genetics often look like?
Often looks at twin studies
Approach looks at nature / nurture - how much of each
What is blending?
Mixing two things together and that outcome being the result of these 2 things
What is genetic throwback?
When a generation is skipped
E.g you have ginger hair even though your parents don’t, but your grandparents did
What are alleles?
2 sets of coding for the same thing - one of these outcompetes the other - one will be recessive and one will be dominant
Heritability meaning?
The proportion of variance in a particular trait that is attributed to genetic factors
To what extent can we explain something by your genetic factor
If you can explain a lot of intelligence by your genetic factor then it must be highly heritable
How is heritability estimated?
At a population level, not individual
0=0 heritability
0.5 =50% heritability
1=100% heritability
Bigger number represents higher level of heritability
Genotype?
= coding
Phenotype
= what ends up happening
Monozygotic twins
Share all of their genetic influences
All of their shared environment influences
Each child has their own nonshared environmental influences
Dizygotic twins
Share half of their genetic influences
All of their shared environmental influences
Each child has their own non shared environmental influences
What have twin studies shown?
Show the effects of genetic factors
Have shown that all traits show substantial heritability
But no traits are 100% heritable
Limitations to twin studies?
Shared environment isn’t really shared
For cognitive abilities, environmental influences make children in a family different from one another
Twin study found 25% of variance in cognitive abilities could be attributed to shared environment
What do adoption studies do?
Compare genetically unrelated children adopted into the same family
What have small studies in adoptive siblings found?
An average IQ correlation
BUT
A different study showed an IQ correlation of only -0.03 - studied 16-22 YO instead of children
Therefore, as you get older, the shared environment has less consequence
The nature of nurture :
Environmental measures show genetic influence - heritabilities of about 25% on average
How does heritability develop?
Heritability of intelligence increases from infancy to adolescence
Intelligence heritability is approx 40% in childhood, but 60% in adulthood
What are gene environment interactions / correlations?
A child with a genetic predisposition for high intelligence seeks out intellectually stimulating activities
