Laughter in response to tickling is a primordial reflex in animals and promotes play behavior and social bonding. But humans also exhibit more complex laughter types such as joyful or taunting laughter to express happiness (or other conscious messages) to peers.
Researchers at the University of Tübingen studied the brain responses of participants listening to ticklish, taunting or joyful laughter using functional MRI [1]. They also asked the participants to identify the laughter types. The participants were able to correctly distinguish the laughs in the majority of cases, though they were less accurate in identifying ticklish laughter.
This study shows that distinguishable brain regions are involved in ticklish and complex laughter types. Ticklish laughter (involving rapid high-pitched sounds) was found to activate brain regions, such as the prefrontal cortex and auditory association cortex, involved in processing complex acoustic signals. The perception of the two complex laughter types, joyful and taunting laughter, on the other hand, activated partially overlapping brain regions involved in social processing.
The researchers, however, observed differences in the strength of connections in brain regions between these two laughter types. During taunting laughter, the data showed stronger connection between auditory association cortices and regions involved in analyzing others’ mental states (mentalizing areas). In the case of joyful laughter, the visual areas were more strongly connected to the mentalizing areas. They suggest that in recognizing joyful laughter, seeing faces plays an important role.
Studies on laughter have implications on clinical disorders such as schizophrenia, depression or autism in which people misinterpret or fail to recognize social signals. Understanding how the brain recognizes laughter can not only offer insights into these disorders but also on human social behavior and language evolution.
[1] Wildgruber et al, PLoS ONE, 2013
By Aarti Swaminathan, PhD Student AG Schmitz
This article originally appeare March 2015, in Vol 08, Issue 01, Humor
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