In social psychology, the emphasis is on understanding how individuals form
beliefs of trustworthiness as a function of their interactions with another person
or entity. In the absence of prior interactions, generalized expectations of trust
are substituted. These expectations can come from many different sources. For
example, the social, cultural or organizational context can provide such clues. A
person's role can be used to infer trust about their abilities, like trusting an engineer,
based on information about institutions that provide the necessary education [ 34 ].
Social groups and culture also provide important clues, depending on to which
degree the individual is part of them, as well as how stable and trusted they are.
In social exchanges, recommendations from a trusted third party can help establish
expectations of trust.
Individuals also substitute simpler heuristics for evaluating trustworthiness, such
as appearance or homophily [ 46 ], i.e., similarity to self in some aspect. These
heuristics are especially active when there is no firsthand or other contextual
information about the trustee. As one gains experience with the trustee, it is expected
that trust evaluation is shaped increasingly by one's personal evaluation of the
trustee [ 6 , 37 , 50 , 64 ].
A common topic of study is the investigation of to which degree these other fac-
tors continue to impact trust evaluation in the presence of firsthand knowledge [ 6 ]. A
personality trait called propensity to trust or disposition moderates the level of trust
in all situations. The propensity varies from trustor to trustor, and can be measured
by Rotter's Interpersonal Trust Scale [ 60 ]. Individuals with high propensity to
trust are not more gullible than low propensity people [ 61 ], and propensity is not
correlated with intellect [ 23 ]. However, high propensity individuals are more likely
to be viewed as trustworthy by others [ 35 ].
From the perspective of cognitive psychology, researchers study how individuals
form impressions about the intent of others by studying the brain activity of
individuals participating in various economic games [ 1 ]. When analysing another's
intent, people tend to focus primarily on their behavior. Even though the behavior of
others is significantly influenced by the specific situations in which the behavior is
observed, people tend to generalize their observations to many others. When form-
ing opinions about another's expected behavior based on second-hand information,
the more distinctive the information is, the more valuable it is. If Alice hears that
Bob has done something, for this to be a useful information about Bob, two things
should be true: Bob's action should not be common to everyone and Bob should
perform this action consistently over time and over different situations. Opinions
formed by second-hand information such as those that come from reputation can
be persistent. Individuals were first told information about others and then played a
trust game with those others, getting firsthand behavioral information [ 11 ]. In these
experiments, the initial impressions were more influential than the actual behavior
to decide to which degree the other can be trusted. This indicates that while actions
have an impact on impressions of trustworthiness, the impact may not be as strong
as that of reputational information. A great deal of firsthand behavioral information
may be needed to overwrite such impressions, such as those developed through
long-term social interactions.