"But performing a task for work or school is very different than doing it in a lab -- there's a lot more pressure in a real world scenario, so they changed the conditions. They told both groups that they'd have another math test, but this time their high performance would earn them cash and their results were going to be examined by math professors. The results of that next test? The score of the HWM [high working memory] guys dipped so badly that they had become just as horrible as the scores of the LWM [low working memory], while the LWM crowd scored just about the same. The stress brought on by the extra incentives didn't affect the stupid guys at all, while the HWM were pissing in their boots."
I don't care that the cite comes from Cracked.com.