Nature-Nurture Flashcards
what are correlation coefficients?
a standardised way to describe the strength and direction of the relationship between variables
small correlation
.15
medium correlation
.25
large correlation
.35
what is intelligence?
an ability to understand complex ideas and adapt to the environment- being able to cope with novel problems
what do intelligence tests attempt to measure?
- verbal ability
- non-verbal reasoning
- working memory
- processing speed
how can the development of intelligence be described?
discontinuity and stability
what is spearman’s ‘positive manifold’?
in large samples, scores within each cognitive domain tend to correlate with each other
what did spearman claim correlation in these tasks was evidence of?
general intelligence (g)
what did cattell and thorndike claim?
these tests measured various kinds of ability
cattell’s two types of intelligence
fluid intelligence and crystallised intelligence
fluid intelligence
the ability to work things out with no previous knowledge
crystallised intelligence
the established store of knowledge from being exposed to culture and environment
what did a meta-analysis of 460 datasets establish?
positive manifold is one of the most replicated findings in psychology
what is factor analysis?
a statistical technique developed by spearman to pull out commonalities and differences between the tests
what is IQ?
a metric to quantify intelligence, and these tests have a normal distribution
what is the mean IQ?
100
what is the standard deviation?
15
what do intelligence tests show strong levels of?
and what is this evidence of?
test-retest reliability and different IQ tests have strong correlations
evidence of the underlying skill of ‘g’
what did deary (2002) find about IQ?
shows strong rank-order stability across the lifespan
when does intelligence increase?
from 11-79
when did intelligence have a marked decline?
from 87-90
when did fluid intelligence see a rapid growth?
during childhood, and a sharp decline upon getting older
a downhill trajectory from 20
when does crystallised intelligence see a massive growth?
during childhood, but this remains fairly stable
what have twin studies been used for?
to understand the role of genetics and environment on intelligence
correlation of MZ and DZ twins on IQ tests
MZ twins found to have a .86 correlation vs .60 for DZ twins
suggests there is a strong genetic component to intelligence, as even MZ twins living apart correlate
twin studies claim that __% of the variance in intelligence is determined by genetic factors
50%, however they are still unable to explain the specific genes involved in intelligence
what did davis and haworth discover about heritability?
heritability of intelligence changes with age, and genetic effects become more significant at later stages of life
- this suggests we are less susceptible to environments as we get older
what is another explanation of davis and haworth’s findings?
it may be that DNA does not change, but rather the relative important of genetic differences for intelligence is changing
what are single nucleotide polymorphisms?
a type of genetic variation
why is it important to identify specific genomic variants?
it makes it possible to identify whether someone has a certain polymorphism
what does research suggest about nucleotide polymorphisms?
that SNPs (individual genes) tend to have very small effects on intelligence
this suggests that intelligence is polygenic- looking at many different SNPs working together
what is a ‘genome-wide polygenic score’?
each individual has one, which consists of counting target alleles
what have recent studies found significant associations between?
GPS and intelligence, but this still accounts for roughly 10% of the variance in intelligence being associated with genetic factors
twin studies vs SNPs
this suggests that not all SNPs have been identified, or that twin studies have overestimated the genetic influence of intelligence
types of environmental influences
biological (nutrition, chemical exposure)
social (schooling, family)
what can children’s IQ be explained by?
range of family factors such as warmth in the home and resources
why is it difficult to explain environmental associations?
the connections may not be driven by social causation (social factors), but rather social selection (genetic factors)
what meta-analysis supports the idea of social causation over social selection
a meta-analysis of quasi experimental studies looked to see if education reform improved education. IQ increased as years in education increased
what can adoption studies be used to look at?
the relative effects of new environment on children’s intelligence
romanian children adopted away from foster homes had a higher IQ than children who remained in the institutions.
what does this suggest?
living with a family environment helped to develop their intelligence and reach their full cognitive potential
it is possible that ______ __________ can moderate genetic influence on IQ
shared environments
what factors can allow children to live up to their genetic potential?
being in a supportive or higher socioeconomic environment
natural tendencies (genetic influences) for intelligence are more fully expressed in nourishing environments
what did results find that heritability increased with?
socioeconomic status
this can be explained in western europe due to free healthcare and childcare
what do shared environments argue against?
the gene-environment dichotomy, by stating that the environment might be able to influence the degree to which genes effect our intelligence
