Exploring the Genetic Etiology of Trust in Adolescents: Combined Twin and DNA Analyses

Abstract

Behavioral 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 United Kingdom’s Twins Early Development Study, we found broad sense heritability estimates of 57% for generalized trust and 51% for trust in friends. Genomic-relatedness-matrix restricted maximum likelihood (GREML) estimates in the same sample indicate that 21% of the narrow sense genetic variance can be explained by common single nucleotide polymorphisms for generalized 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.

Parental Separation and the Formation of Economic Preferences

“…First, our results provide empirical support needed for theories of parenting that use preference transmission as a decision variable (Bisin and Verdier, 2001;Doepke and Zilibotti, 2017). Second, we contribute to evidence on the extent to which risk and trust attitudes are formed by nature (genes) or nurture (family environment) (Cesarini et al, 2008;Hiraishi et al, 2008;Cesarini et al, 2009;Zyphur et al, 2009;Van Lange et al, 2014;Wootton et al, 2016;Harden et al, 2017;Reimann et al, 2017;Nicolaou and Shane, 2019). This literature generally finds a limited, or even zero, role for common family environment.…”

The Heritability of Trust and Trustworthiness Depends on the Measure of Trust

“…It is remarkable that our conclusions would be diametrically different had we based our study only on the general trust measures (stated or behavioral), as in previous trust heritability studies (Cesarini et al, 2008;Hiraishi et al, 2008;Reimann et al, 2017;Sturgis et al, 2010;van Lange et al, 2014;Wootton et al, 2016). Political trust turns out to be only weakly correlated with responses to the general survey trust question and not correlated at all with behavioral trust measures, meaning that we essentially cannot predict the degree to which people trust political leaders from how trusting they are in general.…”

“…We contribute to a still relatively small literature that uses twin variation to estimate heritability of trust attitudes and behavior (Cesarini et al, 2008;Hiraishi et al, 2008;Reimann et al, 2017;Sturgis et al, 2010;van Lange et al, 2014;Wootton et al, 2016). This literature has provided a variety of different heritability estimates of trust and our estimates could be seen as slightly lower, especially for the behavioral trust measures, where we estimate no genetic role.…”

“…no overlap in their environmental and socioeconomic correlates across different measures, further reaffirms that the way they are formed differs and we should be cautious using different trust measures interchangeably. This also raises challenges for research seeking to identify (Benjamin et al, 2012;Nishina et al, 2015;Wootton et al, 2016) as it is not clear that a significant gene for a particular measure of trust will carry over to other domains and measures.…”

“…Only small sample studies have been conducted for (stated) trust, and they estimate heritability between 12-24% (Benjamin et al, 2012;Wootton et al, 2016).…”