In a study conducted at Loma Linda University in US, 20 normal, healthy, older adults watched a funny video distraction-free for 20 minutes, while a control group sat calmly with no video.
They then performed memory tests and had saliva samples analysed for stress hormones, 'ABC News' reported.
Researchers found those who got to laugh the 20 minutes away with the funny video scored better on short-term memory tests.
Salivary levels of the stress hormone cortisol - a memory enemy of sorts - were significantly decreased in the humour group, researchers said.
"Laughing with friends or even watching 20 minutes of humour on TV, as I do daily, helps me cope with my daily stressors," said study author Dr Gurinder S Bains, a PhD candidate in Rehabilitation Sciences.
"Begin by laughing more daily. It will improve your quality of life," Bains said.
Researchers said the less stress you have the better your memory.
Humour reduces stress hormones and blood pressure, and increases mood state, according to Dr Lee Berk, co-author of the study.
Berk said laughter also increases endorphins, sending dopamine to the brain to provide a sense of pleasure and reward.
This, in turn, makes the immune system work better and changes brain wave activity towards what's called a "gamma frequency," amping up memory and recall.