①Have you ever met the following kind of person in school?They do poorly in class.But after an exam，they always feel that they did well.Why are they so confident（自信的）?
②Their confidence comes from the Dunning﹣Kruger effect （邓宁﹣克鲁格效应），Forbes reported.The Dunning﹣Kruger effect is a concept in psychology （心理学）.It says that people who do tasks poorly don't know their poor ability.They also mistakenly feel that they are actually doing well.
③Psychologist David Dunning from Cornell University did an experiment to test this effect.He and his team asked some students to take a grammar test.After finishing the test，the students were asked to estimate（估计） how many questions they answered correctly.
④Dunning and his team found that the lowest scoring students overestimated their abilities.In fact，their actual grammar ability was quite poor，but they thought they were in the top third of test﹣takers.
⑤This doesn't apply just to students，either. Many people in the working world also experience this.One study of software companies found that 32 to 42 percent of workers thought they were in the top 5 percent of their companies.In a study at the University of Nebraska，more than 90 percent of the school's staff thought themselves to be above average（平均值）
⑥But on the other hand，people with average or high skill levels realize they don't know everything.They know that there might be others who are better than them.So they may be more modest （谦虚的） and may not feel very confident about themselves.
⑦However，people who are trapped by the Dunning﹣Kruger effect aren't hopeless.According to Dunning，these people simply don't know that they could be doing better，if they are trained properly，they can see the difference between their previous （之前的）
