|Title of host publication||The SAGE encyclopedia of lifespan human development|
|Publication status||Published - 2018|
Trust and trustworthiness are important pillars of interpersonal, societal, and economic functioning. We provide an overview of how trustworthiness develops across the lifespan. Previous studies point to an increase in trustworthiness during childhood; relatively stable levels throughout adolescence and adulthood; and some evidence suggests a further increase in old age. Young children's lower levels of trustworthiness are mirrored by differences in fundamental motives that drive social behavior, such as concerns for reciprocity and fairness. While reciprocal tendencies emerge early, young children show less fairness concerns. This pattern can be linked to the development of certain cognitive abilities that are necessary to engage in social behaviors beyond indiscriminate selfishness. Children need to exert self-control to resist the temptation of keeping all resources to themselves and they need to engage in perspective-taking to appreciate the negative consequences of their selfishness. Thus, both social and cognitive development should be considered when studying age differences in trustworthiness.