This is the tendency for one’s positive (or negative) traits to “spill over” to other areas of their personality and directly affect others perception of them. A good example of the halo effect is when interpretations of current behaviors carry over to an employee performance evaluation. Let’s say I’m late to work three days in a row. My employer might think it is because I am lazy when actually I was saving a baby from a burning building one day, was carjacked on day two and temporarily abducted by a UFO on day three.
The following video, from “The Science of Attraction” demonstrates the Halo Effect on two groups of young women: