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Published on: June 25, 2019
Genetic and environmental influences on individual differences in printed word recognition
Javier Gayán1, Richard K Olson
1Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK. gayan@wel.ox.ac.uk
Journal of Experimental Child Psychology
|March 1, 2003
Summary
Genetic and environmental factors influence reading skills. Shared and unique genetic effects impact intelligence (IQ), phoneme awareness, and word recognition, particularly phonological and orthographic coding.
Area of Science:
- Behavioral Genetics
- Developmental Psychology
- Cognitive Neuroscience
Background:
- Individual differences in reading skills are influenced by complex genetic and environmental factors.
- Understanding the etiology of reading abilities is crucial for identifying and addressing reading disabilities.
Purpose of the Study:
- To investigate the genetic and environmental influences on individual differences in printed word recognition and related cognitive skills.
- To examine the interplay of genetic factors across intelligence (IQ), phoneme awareness, word recognition, phonological decoding, and orthographic coding.
Main Methods:
- A twin study design involving 440 identical and fraternal twin pairs aged 8–18 years.
- A theoretically driven measurement model to identify latent variables (IQ, phoneme awareness, word recognition, phonological decoding, orthographic coding).
- Cholesky decomposition models to analyze genetic and environmental influences on these latent constructs.
Main Results:
- Evidence of both common and independent genetic effects, as well as non-shared environmental influences on reading-related skills.
- Moderate genetic influences were common between IQ, phoneme awareness, and word recognition.
- Stronger IQ-independent genetic influences were found between phoneme awareness and word recognition, especially phonological decoding.
- Phonological and orthographic coding demonstrated significant common and independent genetic influences.
Conclusions:
- Reading skills are heritable, with both shared and unique genetic factors contributing to their development.
- The findings have implications for understanding different reading models (dual-route, connectionist), subtypes of reading disabilities, and developing effective remediation strategies.
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