Published in 2005: 

Most people believe that they should avoid changing their answer when taking multiple choice tests.  Virtually all research on this topic, however, has suggested that this strategy is ill-founded: Most answer changes are from incorrect to correct, and people who change their answers usually improve their test scores.  Why? …. Changing an answer when one should have stuck with one’s original answer leads to more "if only …" self-recriminations …[making such events] more memorable.