The findings from the University of Portsmouth suggest that chimpanzees’ communication is more similar to humans than was previously known.
The research also found that chimpanzees are able to produce these smile types silently, without being constrained by the accompanying laughing sound, ScienceDaily reported.
Lead researcher Marina Davila-Ross said…
The researchers filmed 46 chimpanzees at the Chimfunshi Wildlife Orphanage and used ChimpFACS –a facial action coding system adapted from the original research by Dr Paul Ekman – designed for chimpanzees– to measure their facial movements. FACS is used by EIA for forensic reports and research and features as a key module in the Behavioral Analysis and Investigative Interviewing module.
Co-author on the paper, Kim Bard, who designed ChimpFACS, said…
The study investigated specific types of smiles that accompany laugh sounds and found that these smile types have the same evolutionary origin as human smiles when they are laughing. It suggests that these smile types of humans must have evolved from positive expressions of ancestral apes.
The study further suggests that flexibility in facial expressions was already present in ancestral apes and emerged long before humans evolved.