III = III + III

Jonah Lehrer writes in Wired:

Here’s a brain teaser: Your task is to move a single line so that the false arithmetic statement below becomes true.

IV = III + III

Did you get it? In this case, the solution is rather obvious – you should move the first “I” to the right side of the “V,” so that the statement now reads: VI = III + III. Not surprisingly, the vast majority of people (92 percent) quickly solve this problem, as it requires a standard problem-solving approach in which only the answer is altered. What’s perhaps a bit more surprising is that nearly 90 percent of patients with brain damage to the prefrontal lobes — this leaves them with severe attentional deficits, unable to control their mental spotlight — are also able to find the answer.

Here’s a much more challenging equation to fix:

III = III + III

In this case, only 43 percent of normal subjects were able to solve the problem. Most stared at the Roman numerals for a few minutes and then surrendered. The patients who couldn’t pay attention, however, had an 82 percent success rate. What accounts for this bizarre result?

The piece is titled ‘Why Being Sleepy and Drunk Are Great for Creativity’, and is about “the unexpected benefits of not being able to focus.” (The next time your loved one asks you to pay attention, just snap back at her that you’re busy being creative.) That might just explain absent-minded geniuses—their absent-mindedness is part of the reason they’re geniuses, and not some regrettable offshoot of their abilities.

Um, what was I saying?