Science-- there's something for everyone

Monday, February 20, 2012

Correcting false information

It can be exceedingly difficult to disabuse people of false information, with one exception.  Apparently, if you quiz people on something, correct their errors, and then give them the exact same quiz five minutes later, they do better.  This is true even if they had been quite confident about their previously held wrong ideas.   Okay, this isn’t particularly surprising or helpful.  But can people still remember the corrected answers a week later?  This was the question Duke University researchers Andrew Butler and Elizabeth Marsh, and Carnegie Mellon psychologist Lisa Fazio set out to answer.

The scientists gave 50 undergraduate volunteers a series of 120 general knowledge questions.  After each question, the correct answer was given. Six minutes after completing the test (and after performing a brief unrelated ‘filler’ task), half the group was given the exact same test again.  The other half would be given the test one week later.

So how did everyone do?  The average correct answer rate on the initial test was 38%.  This doesn’t say great things about our educational system, given that these were college students.  However, the authors optimistically noted that this low number allowed plenty of room to evaluate improvement.  Alas, the students who retook the test six minutes later showed much greater improvement than those who waited a week.  In other words, by a week later, many of the volunteers had already forgotten the corrections.  Still, the fact that people can retain information for six minutes is better than nothing. 

By the way, yours truly got 78% right on an initial run through the test and 90% one week later.  In my defense, it wasn't always clear what the authors were looking for. For example, one question was: "What causes a bull to become angry and charge during a bullfight?"  I initially answered, 'being prodded with spears' but subsequently learned that the answer was supposed to be 'movements of the cape'.