Is someone laughing with you or at you? Your brain can tell the difference, researchers have discovered.

Dr Kai Alter, of Newcastle University, was part of a team which scanned volunteers’ brain activity as they listened to different types of laughter recorded in situations such as being tickled, feeling joy and taunting someone.
 
The volunteers were asked to categorize whether the laughter was happy, mocking, or as a result of being tickled. In the majority of cases they were able to correctly identify the laughs, although they were slightly less accurate at correctly labelling tickling.
 
When listening to taunting laughter, there was a stronger connection between the auditory and ‘mentalising’ areas of the brain, but during joyous laughter, the visual area was more active. This suggests the brain might be recognising the social consequences of the sound of taunting laughter.

Dr Kai Alter, Senior Lecturer in the Institute of Neuroscience said: "Laughter is part of our emotional communication and important to the evolution of our species. Laughing has an advantage as you don't have to say words or long sentences to express emotions. It is just the voice that makes the difference.

"A positive laugh can be contagious as we're laughing with each other and can help form a group however, schadenfreude when you laugh at the misfortune of others makes someone feel lower in the hierarchy so laughter delineates the dynamics in a group."

It may seem trivial, but misunderstanding neutral or positive information is a real issue for how society functions. For example, schizophrenics may perceive happy laughter as mocking; people with depression often see a smile as a smirk and feel social rejection.
 
Better diagnosis and treatment could be achieved through greater understanding of how the brain reacts to laughter in people with these and other conditions, such as autism.
 
The research, which was led by Dirk Wildgruber, professor of neuropsychiatry at Eberhard Karls University of Tubingen, Germany, is published in the current edition of PLOS One.
 
Reference: Wildgruber D, Szameitat DP, Ethofer T, Brück C, Alter K, et al. (2013) Different Types of Laughter Modulate Connectivity within Distinct Parts of the Laughter Perception Network. PLoS ONE 8(5): e63441. doi:10.1371/journal.pone.0063441

published on: 14 May 2013