Laughter stimulates both sides of the brain to enhance learning. It eases muscle tension and psychological stress, which keeps the brain alert and allows people to retain more information. (Humor and Laughter: https://www.helpguide.org/)

Under acute stress, the two hemispheres of the brain become disconnected. Laughter improves creativity and problem-solving, and activates the limbic system in the brain, connecting the right and left sides. It helps you do more whole brain work. (O’Donnell, Sinara Stull."Laugh More at Work to Est Office Stress.  http://www.wsj.com/public/page/news-career-jobs.html)