| Key research Vanleewen key terms | ▪ MZ twins - Monozygotic; identical twins who share 100% of their DNA.
▪ DZ twins - Dizygotic; non-identical twins who share 50% of their DNA.
▪ Genotype - The set of genes that a person has which is responsible for a particular trait.
▪ Phenotype - The way genes are expressed through physical, behavioural and
psychological characteristics |
| Background for Vanleuwen's research | difference in gender in intelligence
Brain structure - different amount of grey matter in different sex brain resulting in different iq's
Genetics - to see if its inhibitory
differences between adopted children and biologival in interlectual abilities
Different IQ between MZ twins and DZ |
| Sample for Vanleuwen | 112 families from the Netherlands Twin registry ( volunteer sampling) |
| Design and Procedure of Vanleuwen | compared intelligence of MZ and DZ twin
childrens- by a cognitive test SPM that consisted of 60 PROBLEMS. this is iq test measures fluid intelligence
adults - APM test |
| Results in Vanleuwen | NO SEX DIFFERENCES
no cultural transmission
the environment factors are likely to interact with your genetic intelligence if you have a naturally low iq
So the MAIN INFLUENCE ON IQ IS GENETIC factors |
| Evaluation of Vanluewen | Useful - Could test at a young age to identify low IQ, and then provide early intervention-support to help develop general cognitive skills.
Research Method – Correlational research – even a perfect correlation of 1 would not allow us to conclude that genes CAUSE intelligence.
Determinism – Suggests that our genes determine who we mate with, and then our children’s intelligence is determined by that, and so on.
Sample – Reasonable size, all Dutch, good to use both types of twin (MZ/DZ), plus siblings. |
| Applications of intelligence | RPM - ravens progressive matrices
it measures genetic/ fluid intelligence
has different tests for different age groups |
| Eval of RPM | Are highly reliable tests – if a person scores well on one occasion, they are highly likely to perform similarly well again.
The validity could be questionable – the tests measure deductive reasoning. Spearman would argue that this is a cognitive skill which is part of ‘g’, so is a valid measure of intelligence.
However, Gardner for example would argue that this is just one type of intelligence (e.g. logical-mathematical) and so the test is not validly measuring intelligence as a whole. SO LACKS CONSTRUCT VALIDITY |
