"The experiments revealed a distinct pattern of neural activity that occurs in response to a funny joke, with the left posterior temporal gyrus and left inferior frontal gyrus seeing the most activity. These regions are normally linked to language comprehension and the ability to adjust the focus of our attention, which would seem to correspond to the process of incongruity-resolution at the heart of a good joke (NeuroImage, vol 21, p 1055).
Further research, conducted by Dean Mobbs, then at Stanford University in California, uncovered a second spike of activity in the brain's limbic system - associated with dopamine release and reward processing - which may explain the pleasure felt once you "get" the joke (Neuron, vol 40, p 1041).
Examining one particular part of the limbic system - the ventral striatum - was especially revealing, as its level of activity corresponded with the perceived funniness of a joke. "It's the same region that is involved in many different types of reward, from drugs, to sex and our favourite music," says Mobbs, now at the MRC Cognition and Brain Sciences Unit in Cambridge, UK. "Humour thus taps into basic rewards systems that are important to our survival."
Yet humour is a far more complex process than primeval pleasures like sex or food. In addition to the two core processes of getting the joke and feeling good about it, jokes also activate regions of the frontal and cingulate cortex, which are linked with association formation, learning and decision-making (Cerebral Cortex, vol 17, p314). The team also found heightened activity in the anterior cingulate cortex and the frontoinsular cortex - regions that are only present in humans and, in a less developed form, great apes. Indeed, the fact that these regions are involved suggests that humour is an advanced ability which may have only evolved in early humans, says Watson, who conducted the research."
