Halo effect
The halo effect (a.k.a. halo error) is a type of bias where someone’s initial positive judgement about someone influences their perceptions of them as a whole.
For example, a manager may appreciate a new employee’s enthusiasm so much that she gives him a glowing performance review, despite have mediocre performance in reality.
The halo effect is a type of cognitive bias because we draw conclusions about one aspect of a person (e.g., job performance) based on our positive impressions of a different aspect (e.g., enthusiasm).
The opposite of the halo effect is called the horn effect, which is when a negative judgement spills over to other areas.
See also: bias