We all know that laughter is the best medicine, but a team of French scientists has discovered that using humor also appears to help toddlers learn new tasks, reports a new study in the journal Cognition and Emotion.

Building on the knowledge that making older children laugh can enhance many aspects of cognition, Rana Esseily and her colleagues designed an experiment to see whether using humor could also have an effect on the ability of infants to learn.

Each of the 18-month-olds selected to participate in the final part of the study observed an adult using a tool to grab an out-of-reach toy. In one group the adult simply played with the toy after retrieving it; but in the other group, the adult threw the toy immediately on the floor, which made half the children in that group laugh.

When Esseily and her colleagues studied their data, they found that the children who laughed at the antics of the adults were able to repeat the action themselves more successfully than those who didn't laugh, as well as those who were included in the 'humorless' control group.

Why laughter seems to be related to the toddlers' ability to learn isn't entirely clear, but Esseily and her team put forward two possible explanations. The first relates to temperament. "In this case, it is not humor per se that may have facilitated learning," the authors suggest, "but [that] temperamentally 'smiley' babies were more likely to engage with the environment and therefore to attempt and succeed at the task." It could also be the case that 'laughing babies' might have higher social skills or cognitive capacities, allowing them to interact more easily with others and making them more amenable to mimicking the actions of others.

The second explanation the authors put forward relates to brain chemistry. It is well known that positive emotions, like laughter or engaging well with an experimenter, can increase dopamine levels in the brain, which in turn has a positive effect on learning. "Thus, the effect observed here might be a general effect due to positive emotion and not to humor or laughter per se," they note.

More research needs to be done into the effect of humor on learning, of course, but parents about to embark on the un-funny business of toilet training might want to keep laughing -- no matter what.