Stumped by a crossword puzzle? Try taking a break to watch a funny TV show. Recent research shows that people in a lighthearted mood more often have eureka moments of sudden inspiration.

Karuna Subramaniam, then at Northwestern University, and her colleagues found that boosting the mood of volunteers increased their likelihood of having an aha! moment that helped solve a word associa­­tion puzzle. Those who watched a Robin Williams comedy special did measurably better at the task using insight than those who watched a quantum electronics talk or a scary movie. The games, in which players must find a word that connects three seemingly unrelated words, have been used for decades to demonstrate creative problem solving.

In the brain, sudden insight is accompanied by increased activity in the brain’s anterior cingulate cortex (ACC) prior to solving each prob­lem. The region is involved in regulating attention; in problem solving, it seems to work in con­junction with other brain areas either to stay focused on a par­ticular strategy or to switch to a new one. Subramaniam found with functional MRI that people in a positive mood had more ACC activity going in to the task, which probably helped prepare the brain to find novel solutions. Participants who watched anx­iety-producing movies such as The Shining, however, showed less activity in the ACC and less creativity in solving the puzzles. [For more on creativity in the brain, turn to “The Unleashed Mind.”]