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Study Finds That Having Power Can Make You Stupid

They had subjects write detailed accounts of times when they had had or had lacked power. They then had them answer a series of factual questions and rate how confident they were about their answers. They found that the people who had been primed to think of themselves as more powerful had more confidence in their answers than the restand yet their answers were actually less accurate. Yes, "confidence in one's answers was inversely correlated with accuracy."
Four follow-up experiments confirmed and expanded the results. The researchers came to a disturbing conclusion:

Not only do overconfident people tend to acquire roles that afford power . . . but the subjective sense of power brought on by these roles causes people to become further overconfident. . . . Finding practical ways to soften and/or hold in check the causal relationship between power and overconfidence represents an important endeavor for future research. Helping the powerful safely escape this perilous aspect of power is not only in the interest of power holders, but is also in the interest of all who are daily impacted by their decisions.

What can you do? One answer, apparently, is to humiliate the powerful. The fifth and final experiment the four conducted found that the tie between power and overconfidence "was eliminated when the powerful were made to feel incompetent."
The full study is being prepared for publication in the journal Organizational Behavior and Human Decision Processes.