Week7
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MANUSCRIPT ID
- Title
Individual differences in executive functions are almost entirely genetic in origin.
- Reference
Friedman NP et al, 2008
- Abstract
Recent psychological and neuropsychological research suggests that executive functions--the cognitive control processes that regulate thought and action--are multifaceted and that different types of executive functions are correlated but separable. The present multivariate twin study of 3 executive functions (inhibiting dominant responses, updating working memory representations, and shifting between task sets), measured as latent variables, examined why people vary in these executive control abilities and why these abilities are correlated but separable from a behavioral genetic perspective. Results indicated that executive functions are correlated because they are influenced by a highly heritable (99%) common factor that goes beyond general intelligence or perceptual speed, and they are separable because of additional genetic influences unique to particular executive functions. This combination of general and specific genetic influences places executive functions among the most heritable psychological traits. These results highlight the potential of genetic approaches for uncovering the biological underpinnings of executive functions and suggest a need for examining multiple types of executive functions to distinguish different levels of genetic influences.
- Input Author
fws
MANUSCRIPT DETAILS
- Introduction/Aims
- What are ‘executive functions’
- ‘an ability for individuals to control their own thoughts an actions’
- Unity and Diversity of EF
- initially thought of as a unitary construct
- most thought of now is at least three (inhibit, update, shift)
- most tasks are ‘impure’: one solution...use latent variables
- Twins
- Allow examination with fancy stats to see additive (a), common environment (c), and nonshared environment (e)
- Method
- ACE modeling of twin data
- Participants
- 582 folks from 293 same-sex twin pairs (colorado longitudinal twin study)
- 316 MZ twins (177 female)
- 266 DZ twins (137 female)
- age=16 or 17 ??
- IQ mean =102, sd =11
- Tasks
- Inhibiting
- Antisaccade
- StopSignal
- Stroop
- Inhibiting
- Updating
- keeptrack
- lettermemory
- spatial 2back
- Updating
- Shifting
- letter-number
- color-shape
- category
- Shifting
- WAIS and some perceptual speed measures too
- Results
- Discussion
- Executive functions show overwhelming strong genetic influence, and its not all related to a primary 'g' factor
- Implications for future research using endophenotypes, latent variable approaches, and the search for the neurobiology of complex behaviors
