"She tried to be chipper, and when they asked her age, she did this little shimmy" — because she was on TV.

"We could see that Susan Boyle thought "you’re supposed to be kind of sexy and personable, and she got it wrong... Nothing sort of triggers our contempt more than something trying to be acceptable and then failing."

Consider the brain and its stereotypes:

On a very basic level, judging people by appearance means putting them quickly into impersonal categories, much like deciding whether an animal is a dog or a cat. “Stereotypes are seen as a necessary mechanism for making sense of information,” said David Amodio, an assistant professor of psychology at New York University....

Eons ago, this capability was of life-and-death importance, and humans developed the ability to gauge other people within seconds....

One reason our brains persist in using stereotypes, experts say, is that often they give us broadly accurate information, even if all the details don’t line up. Ms. Boyle’s looks, for example, accurately telegraphed much about her biography, including her socioeconomic level and lack of worldly experience.

Her behavior on stage reinforced an outsider image. David Berreby, author of “Us and Them,” about why people categorize one another, said the TV audience may have also judged her harshly because, in banter with the judges before singing, she appeared to be trying, awkwardly, to fit in....

[John F. Dovidio, a psychology professor at Yale] said that encountering discrepancies to stereotypes probably “creates a sort of autonomic arousal” in our peripheral nervous system, triggering spikes of cortisol and other indicators of stress. “That autonomic arousal is going to motivate us to do something in that situation,” he said, especially if the situation is dangerous.

But we're not out on the savannah in evolutionary times. We're sitting at home on our comfy sofas, experiencing the thrill that was once danger.