http://www.hindustantimes.com/news/181_406342,0050.htm
Laughter - the missing link?
ANI
London, October 7
The rules for how emotion is encoded behaviourally were laid down in a common ancestor that humans shared with other great apes, suggests a new study that also concludes that the origins of laughter may pre-date human evolution.
Studying special sounds and gestures made by infant bonobos also known as pygmy chimpanzees when they are tickled, the researchers found that when it was tickled, the bonobo combined vocalisations and facial gestures much like those made by human infants, says the report in ABC Online.
Dr. Elke Zimmermann of the Institute of Zoology at the Tieraerztliche Hochschule in Hanover conducted a sophisticated analysis of the recordings and compared them with sounds made by human babies when they are tickled.
She found that the bonobo's vocalizations followed broadly the same spectrographic pattern - a technique that depicts the changes in frequency and intensity of the sound over time - as that of human infants, except that the bonobo's laugh was at a higher frequency.
Infant bonobos and humans both combine those sounds with a facial gesture known as a "relaxed open-mouth display".
Zimmerman believes that her findings confirm a hypothesis that laughter originated in primates, as a universal signal of well being in a playful situation to help regulate social interactions, the report says.
"A pre-human evolutionary origin for laughter could also explain why it is still present in deaf and blind infants, and why it fulfils the same role - and sounds the same - in people from different cultures," it says.
Laughter is well documented in common chimpanzees, with observations of both wild and captive chimpanzees revealing that they even share with humans the same ticklish anatomical regions - the armpits and belly.
