Trust is built through iterative exchange. This is Bayesian priors - default is average, and only moves on the introduction of new information.
Lots of examples of this. In 1950's westerns, if a stranger comes to a small town, the default treatment is a guarded form of hospitality with a health measure of suspicion. If you are dating someone new, you are by default understood as the average first date partner, and the average first date partner is not a great match.