Tickling laughter produces different brain response than social laughter

Tickling laughter produces different brain response than social laughter

When we hear someone laughing because they are being tickled, the connections in our brains respond differently than when we hear social laughter, such as that which expresses joy or accompanies mocking behavior. This was the finding of a study by researchers in Germany who conclude that different patterns in the brain's "laughter perception network" are activated by different kinds of laugh.

Dirk Wildgruber and colleagues from the University of Tuebingen write about their study in a paper published online in the open access journal PLOS ONE on 8 May.

Researchers who study laughter suggest that laughter types with complex social functions, and with positive and negative connotations, such as expressing happiness or mocking, evolved from tickling laughter, a reflex that in primates helps to reinforce play and increase social bonding.

Also, in contrast to the primordial reflex nature of tickling laughter, "complex social laughter" occurs in a wide variety of social settings and can be used consciously to influence and modify other people's attitudes and behaviors, note the authors in their introduction.

"Laughing at someone and laughing with someone leads to different social consequences," Wildgruber explains in a statement.

"Specific cerebral connectivity patterns during perception of these different types of laughter presumably reflect modulation of attentional mechanisms and processing resources," he adds.

For their study, he and his colleagues used functional magnetic resonance imaging (fMRI) to observe patterns in the brains of 18 healthy, medication-free, volunteers (9 men and 9 women of average age 26 years) as they listened to three types of human laughter: joy, taunt and tickling.

They noticed that listening to joyous or taunting laughter activated brain regions normally linked to processing complex social information.

But, presumably because tickling laughter produces more complex sound patterns than the other types of laughter, it activated parts of the brain normally associated with processing acoustic complexity.

This was shown in connectivity changes between areas in the "prefrontal cortex and the auditory association cortex, potentially reflecting higher demands on acoustic analysis," write the researchers.

In contrast, the jouous or taunting laughter, because of its higher degree of "socio-relational information", was linked to "increases of connectivity between auditory association cortices, the right dorsolateral prefrontal cortex and brain areas associated with mentalizing as well as areas in the visual associative cortex," they note.

Previous studies have shown that different patterns of connectivity in the brain affect health and disease. Although there has been a lot of work on how these are affected by listening to speech, this is thought to be one of the first few investigations to examine the effect of non-verbal vocal cues.

In another recent study that used fMRI scans of the brain, US scientists showed how for the first time, it may be possible to "see" pain, and develop a reliable way for doctors to quantify objectively how much pain patients are feeling.

See What Happens When You Tickle a Rat | National Geographic (Video Medical And Professional 2020).

Section Issues On Medicine: Psychiatry