CHIMPS smile and laugh with each other to show how they feel, according to a new study.
University of Portsmouth researchers say chimpanzees’ communication has more in common with our own than was previously believed.
Until now we didn’t know chimps could also flexibly produce facial expressions free from their vocalisationsMarina Davila-Ross
Marina Davila-Ross, from the university’s Centre for Comparative and Evolutionary Psychology, said chimps can smile without laughing, just like humans.
She said: ‘Humans have the flexibility to show their smile with and without talking or laughing. This ability to flexibly use our facial expressions allows us to communicate in more explicit and versatile ways, but until now we didn’t know chimps could also flexibly produce facial expressions free from their vocalisations.’
Researchers filmed 46 chimpanzees at the Chimfunshi Wildlife Orphanage in Zambia to measure facial movements.
Professor Kim Bard, who designed a coding system used in the research, said: ‘The coding system allows us to examine very subtle facial movements and compare human and chimpanzee facial expressions, based on their shared musculature.’
The study found that chimp smiles have the same evolutionary origin as human smiles.
The research suggests that these smile types of humans must have evolved from positive expressions of ancestral apes.
The study also suggests that flexibility in facial expressions was already present in ancestral apes and emerged long before humans evolved.
But Dr Davila-Ross said there were still key differences between humans and our ape ancestors.
She said: ‘Chimps only rarely display crow’s feet when laughing, but this trait is often shown by laughing humans.
‘Then, it is called Duchenne laughter, which has a particularly positive impact on human listeners.’