Exploring the genetic aetiology of trust in adolescents: Combined twin and DNA analyses

Behavioural traits generally show moderate to strong genetic influence, with heritability estimates of around 50%. Some recent research has suggested that trust may be an exception because it is more strongly influenced by social interactions. In a sample of over 7,000 adolescent twins from the UK’s Twins Early Development Study we found broad sense heritability estimates of 57% for generalised trust and 51% for trust in friends. GREML estimates in the same sample indicate that 21% of the narrow sense genetic variance can be explained by common single nucleotide polymorphisms for generalised trust and 43% for trust in friends. As expected, this implies a large amount of unexplained heritability, although power is low for estimating DNA-based heritability. The missing heritability may be accounted for by interactions between DNA and the social environment during development or via gene-environment correlations with rare variants. How these genes and environments correlate seem especially important for the development of trust.