Twins and their singleton siblings differ in language, cognition, and social-emotional development

Emily Wood; Anna Brown; Sophie von Stumm

doi:10.1093/chidev/aacaf029

Twins and their singleton siblings differ in language, cognition, and social-emotional development

Emily Wood
, Anna Brown
, Sophie von Stumm

School of Psychology and Behavioural Sciences

Research output: Contribution to Journal › Article › peer-review

Abstract

This study compared the language, cognition, and social-emotional development between twins and their younger singleton siblings at the ages 2, 3, 4, and 7 years. Data were collected 1996–2004 from 851 sibling trios from the Twins Early Development Study (TEDS; 50.2% female; 93.2% White British). Distributions were comparable between twins and singletons across domains, indicative of mean rather than variance discrepancies. Twins performed worse than singletons in language, cognition, and social-emotional development across ages, with small to moderate effect sizes (d = 0.17–0.62). An exception was language at age 7 years, when twins exceeded their singleton siblings (d = −0.35). Overall, twins and their singleton siblings differed in development across domains and their differences in language reversed during childhood.

Original language	English
Article number	aacaf029
Pages (from-to)	649-661
Number of pages	13
Journal	Child Development
Volume	97
Issue number	3
DOIs	https://doi.org/10.1093/chidev/aacaf029
Publication status	Published - 24 Mar 2026

Bibliographical note

Data Access Statement

Data availability The data necessary to reproduce the analyses presented here are available upon request to the TEDS steering committee (https:// www. teds. ac. uk/ researchers/ teds-data-access-policy) and the materials are publicly accessible (www. teds. ac. uk/ datadictionary/ home. htm). Our analysis code is not publicly accessible. This study was preregistered on the Open Science Framework (https:// osf. io/ q98ge).

Supplementary material is available at Child Development online.

Keywords

Child
Child Development/physiology
Child, Preschool
Cognition/physiology
Emotions/physiology
Female
Humans
Longitudinal Studies
Male
Siblings/psychology
Twins/psychology

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Wood_et_al_2026_Twins_and_their_singleton_siblings_differ_in_language,_cognition,_and_social-emotional_developmentFinal published version, 1.75 MBLicence: CC BY

Cite this

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title = "Twins and their singleton siblings differ in language, cognition, and social-emotional development",

abstract = "This study compared the language, cognition, and social-emotional development between twins and their younger singleton siblings at the ages 2, 3, 4, and 7 years. Data were collected 1996–2004 from 851 sibling trios from the Twins Early Development Study (TEDS; 50.2\% female; 93.2\% White British). Distributions were comparable between twins and singletons across domains, indicative of mean rather than variance discrepancies. Twins performed worse than singletons in language, cognition, and social-emotional development across ages, with small to moderate effect sizes (d = 0.17–0.62). An exception was language at age 7 years, when twins exceeded their singleton siblings (d = −0.35). Overall, twins and their singleton siblings differed in development across domains and their differences in language reversed during childhood.",

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author = "Emily Wood and Anna Brown and \{von Stumm\}, Sophie",

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doi = "10.1093/chidev/aacaf029",

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AU - Brown, Anna

AU - von Stumm, Sophie

N1 - © The Author(s) 2026. Published by Oxford University Press on behalf of the Society for Research in Child Development.

PY - 2026/3/24

Y1 - 2026/3/24

N2 - This study compared the language, cognition, and social-emotional development between twins and their younger singleton siblings at the ages 2, 3, 4, and 7 years. Data were collected 1996–2004 from 851 sibling trios from the Twins Early Development Study (TEDS; 50.2% female; 93.2% White British). Distributions were comparable between twins and singletons across domains, indicative of mean rather than variance discrepancies. Twins performed worse than singletons in language, cognition, and social-emotional development across ages, with small to moderate effect sizes (d = 0.17–0.62). An exception was language at age 7 years, when twins exceeded their singleton siblings (d = −0.35). Overall, twins and their singleton siblings differed in development across domains and their differences in language reversed during childhood.

AB - This study compared the language, cognition, and social-emotional development between twins and their younger singleton siblings at the ages 2, 3, 4, and 7 years. Data were collected 1996–2004 from 851 sibling trios from the Twins Early Development Study (TEDS; 50.2% female; 93.2% White British). Distributions were comparable between twins and singletons across domains, indicative of mean rather than variance discrepancies. Twins performed worse than singletons in language, cognition, and social-emotional development across ages, with small to moderate effect sizes (d = 0.17–0.62). An exception was language at age 7 years, when twins exceeded their singleton siblings (d = −0.35). Overall, twins and their singleton siblings differed in development across domains and their differences in language reversed during childhood.

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KW - Cognition/physiology

KW - Emotions/physiology

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KW - Twins/psychology

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Twins and their singleton siblings differ in language, cognition, and social-emotional development

Abstract

Bibliographical note

Data Access Statement

Keywords

Access to Document

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