What is the acquaintanceship effect, and what boundary condition did Colvin and Funder (1991) discover? Provide a clear example to illustrate this boundary condition.

The acquaintanceship effect refers to the phenomenon where people tend to rate individuals they know more positively than those they do not know. This effect suggests that familiarity with someone can lead to more favorable evaluations of that person.

Colvin and Funder (1991) discovered a boundary condition for the acquaintanceship effect, finding that it is stronger for positive traits than for negative traits. In other words, people are more likely to rate their acquaintances more positively than strangers, especially when it comes to positive characteristics.

For example, imagine a coworker who is known for being friendly and helpful. Even if this coworker has some flaws or negative traits, their acquaintances are more likely to overlook these and focus on their positive qualities. This illustrates the boundary condition discovered by Colvin and Funder, showing that the acquaintanceship effect is stronger for positive traits.