Temperament has been suggested to be influenced by genetic and environmental factors. The current study examined genetic shared environmental and unique environmental factors accounting for variation in Fear, Effortful Control (EC), and Frontal Asymmetry (FA) in 4- to 6-year-old children using bivariate behavioral genetic modeling. We included a total of 214 same-sex twin pairs: 127 monozygotic (MZ) and 87 dizygotic (DZ) pairs. FA was measured during a rest electroencephalogram (EEG) recording, and Fear and EC were measured using parent report. Results show that differences between twins were best explained by genetic factors (about a quarter of the variance) and unique environmental factors (about three quarters of the variance). However, the cross-trait, within-twin correlations were not significant, implying no overlapping genetic or environmental factors on Fear and EC or on Fear and FA. Future research should try to elucidate the large role of unique environmental factors in explaining variance in these temperament-related traits.

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Keywords Behavioral genetics, Early childhood, Frontal EEG asymmetry, Temperament
Persistent URL dx.doi.org/10.1016/j.jecp.2018.11.015, hdl.handle.net/1765/113405
Journal Journal of Experimental Child Psychology
van Wijk, I.C. (Ilse C.), Huffmeijer, R, Bosdriesz, J.R. (Jizzo R.), Bakermans-Kranenburg, M.J, Kolijn, L. (Laura), van IJzendoorn, M.H, … van den Bulk, B.G. (Bianca G.). (2019). Behavioral genetics of temperament and frontal asymmetry in early childhood. Journal of Experimental Child Psychology, 179, 348–361. doi:10.1016/j.jecp.2018.11.015