Published: September 29, 2021

Kettlewell, N. & Tymula, A. (2021). ‘The Heritability of Trust and Trustworthiness Depends on the Measure of Trust’, Life Course Centre Working Paper Series, 2021-19. Institute for Social Science Research, The University of Queensland.


Nathan Kettlewell and Agnieszka Tymula. 

Download: Life Course Centre Working Paper 2021-19

Non-technical summary:

Trust is an essential foundation of any well-functioning society. A lack of trust has been found to have devastating long-term consequences on outcomes such as health and life expectancy. The COVID-19 pandemic has intensified the importance of public trust in the government to effectively enforce lockdowns, safety mandates, and a smooth vaccine rollout. Despite its importance, a firm understanding of the genetic and environmental determinants of trust remains elusive.

In this paper, we use a sample of 1,120 twins to estimate the impact of genetic and environmental factors on trust in general and trust in politicians specifically. The twin sample includes both identical (monozygotic) and non-identical (dizygotic) twins. The following distinct measures of trust are compared: political trust based on survey responses, general self-reported trust based on survey responses and behavioral trust and trustworthiness using an incentivized trust game. Heritability, which indicates the influence of genetic factors on a particular trait, is estimated by comparing the correlations in these four measures monozygotic and dizygotic twins. We also explore what unique environment factors are correlated with trust after removing genetic and common environment factors.

We find that the extent to which genes and environment explain trust differs substantially across different measures of trust. General trust measured using the survey question is found to be 29% genetically determined with the rest determined by environmental factors unique to each twin. In contrast, there is no genetic influence on behavioral trust, while around 15% of variation is explained by common environment. We also provide the first evidence on the heritability of political trust, which we estimate to be 37% genetically determined. The environment common to twins plays essentially no role in political trust, suggesting that the degree of trust placed in politicians does not depend on family upbringing. Trust in politicians is found to be correlated with the largest number of socioeconomic and demographic measures, with people who are more worried about health and economic losses due to COVID-19 reporting lower levels of political trust.

Our paper indicates that political trust differs from general trust and cannot be well approximated with general survey or behavioural economics trust measures. It appears that worry about pandemic outcomes is associated with reduced trust in politicians but not trust in general. These results highlight the importance of measuring trust in a context because its genetic and environmental determinants differ substantially across the four measures.