A new study investigates the neuroscience of jokes.
Researchers from the University of Southern California (USC) in Los Angeles recently undertook a rather ambitious project: they set out to spy on the neural correlates of creating a joke.
The study was led by a USC doctoral student, Ori Amir, and Irving Biederman, a professor of psychology and computer science.
Creativity is a muddy area of research; it is nebulous and ethereal by its very nature. However, regardless of these difficulties (and perhaps because of them), many researchers have set their sights on unpicking the processes that underly creativity.
Earlier studies have taken images of the brain as it writes poetry, improvises jazz, and draws pictures, but humor offers a unique avenue to understanding the creative process.
Humor and the study of creativity
Humor has a clear beginning, middle, and end, and it also takes place over a relatively short space of time - which is convenient for brain imaging. Additionally, the end product is easy to assess; Biederman need only ask: "Does it make you laugh?" It's much simpler than rating the quality of a doodle, haiku, or musical jam.
The study enrolled professional and amateur comedians, as well as a control group of non-comedians.
Each participant viewed a cartoon from the New Yorker without any text and were asked to come up with their own accompanying captions. They wrote two versions of text - one mundane and one funny.
As this task was completed, their brains were scanned using functional magnetic resonance imaging (fMRI). Afterward, a panel assessed each caption for its humor level.
Once the data from the fMRI scans had been analyzed, two sections of the brain were shown to be particularly busy during the creation of humorous comments:
- Medial prefrontal cortex - an area at the front of the brain thought to be involved in learning associations between locations and events, and the appropriate emotional responses. It helps us respond correctly in social interactions.
- Temporal association regions - part of the temporal lobe thought to be involved in the recognition and identification of complex stimuli.
Interestingly, the activation in these particular regions was different depending on the level of comedic expertise. As Amir explains: "What we found is that the more experienced someone is at doing comedy, the more activation we saw in the temporal lobe."
The temporal lobe receives sensory information and plays a pivotal role in understanding speech and imagery. It also appears to be the region where semantic and abstract information converges with remote associations.
Conversely, non-comedians and amateur comedians saw less activity in the temporal lobe and more activity in the prefrontal cortex, an area that deals with executive functions such as complex planning and decision-making.
"The professional improv comedians let their free associations give them solutions. The more experience you have doing comedy, the less you need to engage in the top-down control and the more you rely on your spontaneous associations."
Amir and Biederman also found that the independent funniness ratings were highest for captions created when there was more activity in the temporal regions of the brain.
The importance of the medial prefrontal cortex
In other studies investigating the neural activity that underpins humor, the medial prefrontal cortex often makes an appearance. Amir says: "The question is, what does it do exactly? It seems like it's not the source of creativity, but rather the cognitive control top-down director of the creative process. The creativity itself appears to occur elsewhere depending on the creative task."
The current study adds a new layer to previous research conducted at Biederman's Image Understanding Laboratory. His earlier work looking at the cortical basis of high-level visual recognition found that the same regions in the temporal lobe were activated. Humor and the appreciation of a beautiful vista both appear to use similar parts of the brain.
Biederman also notes that the activation, and therefore pleasure, associated with any experience diminishes with each repetition. This, he theorizes, is why humans tend to be "infovores," eternally driven to find new experiences, forever craving new information (and jokes).