trust an individual has in members of a different group. This could be members of a different ethnic group, or citizens of a different country, for example. In-group trust is that which is placed in members of one's own group. Trust in neighbors considers the relationships between individuals who share a common residential environment. Influence of ethnic diversity Several dozen studies have examined the impact of ethnic diversity on social trust. Research published in the Annual Review of Political Science concluded that there were three key debates on the subject: Why does ethnic diversity modestly reduce social trust? Can contact reduce the negative association between ethnic diversity and social trust? Is ethnic diversity a stand-in for social disadvantage? The review's meta-analysis of 87 studies showed a consistent, though modest, negative relationship between ethnic diversity and social trust. Ethnic diversity has the strongest negative impact on neighbor trust, in-group trust, and generalized trust. It did not appear to have a significant impact on out-group trust. The limited size of the impact means apocalyptic claims about it are exaggerated. Psychology In psychology, trust is believing that the person who is trusted will do what is expected. According to the psychoanalyst Erik Erikson, development of basic trust is the first state of psychosocial development occurring, or failing, during the first two years of life. Success results in feelings of security and optimism, while failure leads towards an orientation of insecurity and mistrust possibly resulting in attachment disorders. A person's dispositional tendency to trust others can be considered a personality trait and as such is one of the strongest predictors of subjective well-being. Trust increases subjective well-being because it enhances the quality of one's interpersonal relationships; happy people are skilled at fostering good relationships. Trust is integral to the idea of social influence: it is easier to influence or persuade someone who is trusting. The notion of trust is increasingly adopted to predict acceptance of behaviors by others, institutions (e.g. government agencies) and objects such as machines. Yet once again, perceptions of honesty, competence and value similarity (slightly similar to benevolence) are essential. There are three different forms of trust commonly studied in psychology. Trust is being vulnerable to someone even when they are trustworthy. Trustworthiness are the characteristics or behaviors of one person that inspire positive expectations in another person. Trust propensity is the tendency to make oneself vulnerable to others in general.