NotesFAQContact Us
Search Tips
Peer reviewed Peer reviewed
Direct linkDirect link
ERIC Number: EJ781868
Record Type: Journal
Publication Date: 2008
Pages: 13
Abstractor: Author
Reference Count: 0
ISSN: ISSN-0160-2896
g in Middle Childhood: Moderate Genetic and Shared Environmental Influence Using Diverse Measures of General Cognitive Ability at 7, 9 and 10 Years in a Large Population Sample of Twins
Davis, Oliver S. P.; Arden, Rosalind; Plomin, Robert
Intelligence, v36 n1 p68-80 Jan-Feb 2008
A 2003 paper in this journal reported results from a large sample of twins assessed at 2, 3 and 4 years of age on parent-administered tests and reports of their verbal and nonverbal ability. We found clear evidence for phenotypic general cognitive ability (g) that accounted for about 50% of the variance, for modest genetic influence on g (about 25% of the variance), and for substantial shared environmental influence (about 65%). As part of the same longitudinal study, we assessed g at 7 years using telephone-administered tests (4530 pairs), at 9 years using parent-supervised booklets mailed to the homes (2886 pairs), and at 10 years using tests administered online (2348 pairs). Despite very different measurement techniques, consistent evidence was found for phenotypic g accounting for about 50% of the variance. Compared to early childhood, g scores in middle childhood showed stronger genetic influence (about 40%) and more modest shared environmental influence (about 30%). Longitudinal analysis revealed strong genetic correlations (r = 0.71-0.81) across age and method of administration, with genes (about 65%) and shared environment (about 35%) accounting for stability, while genes, shared environment and non-shared environment all contributed to change.
Elsevier. 6277 Sea Harbor Drive, Orlando, FL 32887-4800. Tel: 877-839-7126; Tel: 407-345-4020; Fax: 407-363-1354; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A