George Vaillant described the use of humor as a “mature” defense mechanism - a primarily adaptive technique to help us to cope with tense or stressful situations. Looking for a funny aspect in an environment in which we lack control can help us to endure it, and can even be an altruistic act in helping others to better cope as well.

When you hear someone laugh behind you, you probably picture them on the phone or with a friend – smiling and experiencing a warm, fuzzy feeling inside. Chances are just the sound of the laughter could make you smile or even laugh along. But imagine that the person laughing is just walking around alone in the street, or sitting behind you at a funeral. Suddenly, it doesn’t seem so inviting.

The truth is that laughter isn’t always positive or healthy. According to science, it can be classified into different types ranging from genuine and spontaneous to simulated (fake), stimulated (for example by tickling), induced (by drugs) or even pathological. But the actual neural basis of laughter is still not very well known – and what we do know about it largely comes from pathological clinical cases.

Laughter and the appreciation of humor are vital components of adaptive social, emotional and cognitive function. Surprisingly, they are not uniquely human. Primates and apes also enjoy a good chuckle. This may have evolved because it helps them survive. Laughter is, after all, a communal activity which promotes bonding, diffuses potential conflict and eases stress and anxiety. But it loses its momentum quickly when indulged in alone (solitary laughter can have ominous connotations).

Despite the dark side of laughter, there is no denying that laughter generally induces warm fuzzy feelings. We know that laughing enhances cardiovascular function, fortifying our immune and endocrine systems.

We also know that positive, “benevolent humor” – “laughing with” rather than “laughing at” others – is especially rewarding. Indeed the way our brains process other peoples’ laughter seems to indicate that laughing with someone has more emotional depth and is more pleasurable than laughing at them.