Scientists from Institut Du Cerveau (Paris Brain Institute), France, and Bar-Ilan University in Tel Aviv, Israel, have made an intriguing discovery regarding the cognitive and neuronal mechanisms underlying humor appreciation. In a study published in the journal Neuropsychologia, the researchers found that high-frequency neural activity, typically associated with tasks requiring significant cognitive engagement, also plays a crucial role in humor appreciation.
Previous studies have suggested the involvement of the temporal lobe in processing amusing stimuli or stimuli associated with goofiness. To delve deeper into this phenomenon, the scientists conducted intracerebral electrophysiological recordings on 13 epileptic patients who had been implanted with deep brain electrodes as part of their pre-surgical assessment for refractory epilepsy. This technique allowed them to examine neuronal activity with exceptional precision at the millisecond scale across multiple cortical areas.
The patients were asked to watch a three-minute excerpt from Charlie Chaplin’s classic film “Circus” (1928), while their brain activity was monitored. Beforehand, a group of healthy volunteers had evaluated the amusing nature of each scene frame by frame. By comparing the neural activity recorded during the funniest and least funny scenes, the researchers made a fascinating observation.
“We observed that the funniest sequences were associated with an increase in high-frequency gamma waves and a decrease in low-frequency waves,” explained Vadim Axelrod, the leader of the experiment. These findings highlight the link between high-frequency neural activity, which is typically seen during cognitively demanding tasks, and the appreciation of humor.
Notably, the inverse relationship between high and low frequencies was predominantly observed in temporal lobe regions but not in other brain areas. This suggests that the processing of humorous content may vary across the cortex, depending on specific brain regions and their functions.
According to a prominent theory, humor processing involves two complementary mechanisms and neural circuits: cognitive and emotional. Initially, cognition is engaged to detect an incongruous element in reality, setting the stage for humor. Subsequently, the emotional neural circuit generates positive emotions associated with this incongruity, leading to the perception of humor.
The researchers’ findings support this theory, indicating the prominent role of the temporal lobe in humor appreciation. The anterior parts of this brain region, known for their involvement in semantic memory, are likely responsible for scene analysis and the detection of incongruous content. On the other hand, the activation of posterior temporal lobe regions may correspond to understanding the unusual and amusing aspects of social interactions.
This study sheds light on the neural signatures of humor appreciation and provides valuable insights into how the brain processes humor. Further research in this field may contribute to our understanding of cognitive and emotional mechanisms underlying human laughter and pave the way for potential applications in psychology, neurology, and entertainment industries.