Temperament, Emotion, and Cognition at Fourteen Months: The MacArthur Longitudinal Twin Study


  • This study is supported by the John D. and Catherine T. MacArthur Foundation through its Research Network on Early Childhood Transitions. We wish to thank the families who contributed their time and effort, as well as the many research assistants at the University of Colorado, Harvard University, and Yale University who were involved in data collection, behavioral coding, and data management. Dr. Emde is supported in part by NIMH Research Scientist Award 5 K02 MH36808.

Address reprint requests to: Robert N. Emde, M.D., Department of Psychiatry, Box C268–69, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262.


200 pairs of twins were assessed at 14 months of age in the laboratory and home. Measures were obtained of temperament, emotion, and cognition/language. Comparisons between identical and fraternal twin correlations suggest that individual differences are due in part to heritable influences. For temperament, genetic influence was significant for behavioral observations of inhibition to the unfamiliar, tester ratings of activity, and parental ratings of temperament. For emotion, significant genetic influence was found for empathy and parental ratings of negative emotion. The estimate of heritability for parental report of expression of negative emotions was relatively high, whereas that for expression of positive emotions was low, a finding consistent with previous research. For cognition and language, genetic influence was significant for behavioral indices of spatial memory, categorization, and word comprehension. Shared rearing environment appears influential for parental reports of language and for positive emotions, but not for other measures of emotion or for temperament.