The opposite is also true: a "negative halo effect" can be easily observed, wherein "bad" traits are also similarly grouped and feed on each other.
An interesting part of halo effects is that people seem to understand them on an instinctual level - not enough to get rid of them, but enough to exploit them...
I've drawn an extremely strong correlation in a particular online game between having a marijuana reference in one's handle and being bad at the game; being bad is not strongly linked with marijuana references, but that's only because they're in the extreme minority of the population; if you're sporting a "420", you're almost definitely underperforming. I've never bothered forming a hypothesis as to why this is, but it is.
So one day I decide to try a little experiment - for funsies, nothing rigorously scientific, just a "see what happens" thing - and predict aloud that an ally with a name referencing marijuana would perform poorly compared to the other players in the game. I turned out to be right (he was even worse than expected), but the interesting part was his response:
He implied my prediction was wrong, evidenced by that he was writing his college thesis on the effects of THC on the body.
The only way this statement makes sense is if we trace it through an expectation on his part that he can rebut the argument using the halo effect. "I am extremely accomplished academically," I could almost read on the screen, "Therefore, I am not a poor performer in this online video game."
I suspect the intended implication was more like “I know what the effects of marijuana on humans are, and they don't include making people worse at MMORPGs, so just because I smoke marijuana doesn't mean you can conclude I must be bad at this game”.
The affect heuristic is how an overall feeling of goodness or badness contributes to many other judgments, whether it’s logical or not, whether you’re aware of it or not. Subjects told about the benefits of nuclear power are likely to rate it as having fewer risks; stock analysts rating unfamiliar stocks judge them as generally good or generally bad—low risk and high returns, or high risk and low returns—in defiance of ordinary economic theory, which says that risk and return should correlate positively.
The halo effect is the manifestation of the affect heuristic in social psychology. Robert Cialdini summarizes:1
The influence of attractiveness on ratings of intelligence, honesty, or kindness is a clear example of bias—especially when you judge these other qualities based on fixed text—because we wouldn’t expect judgments of honesty and attractiveness to conflate for any legitimate reason. On the other hand, how much of my perceived intelligence is due to my honesty? How much of my perceived honesty is due to my intelligence? Finding the truth, and saying the truth, are not as widely separated in nature as looking pretty and looking smart . . .
But these studies on the halo effect of attractiveness should make us suspicious that there may be a similar halo effect for kindness, or intelligence. Let’s say that you know someone who not only seems very intelligent, but also honest, altruistic, kindly, and serene. You should be suspicious that some of these perceived characteristics are influencing your perception of the others. Maybe the person is genuinely intelligent, honest, and altruistic, but not all that kindly or serene. You should be suspicious if the people you know seem to separate too cleanly into devils and angels.
And—I know you don’t think you have to do it, but maybe you should—be just a little more skeptical of the more attractive political candidates.
1Robert B. Cialdini, Influence: Science and Practice (Boston: Allyn & Bacon, 2001).