Are you having a laugh? Videos reveal chimps smile like humans (but don't have to worry about crow's feet)

  • Experts filmed 46 chimps at the Chimfunshi Wildlife Orphanage in Zambia
  • They used facial coding software called ChimpFACS to track movements
  • Study investigated specific types of smiles that accompany laugh sounds
  • And found these smile types have the same evolutionary origin as human smiles when they are laughing

By Victoria Woollaston for MailOnline

Published: 13:00 EST, 10 June 2015 | Updated: 06:54 EST, 11 June 2015

Chimpanzees have the same types of smiles as humans when laughing and don't need to make a sound to be understood.

By analysing video footage of chimps playing, researchers found six key facial movements that are seen in both the wild animals, and humans. 

And they claim this is the first evidence that chimps, like humans, can flexibly produce facial expressions without making corresponding vocal sounds.

Scroll down for video 

By analysing video footage of chimps playing, researchers found six key facial movements that are seen in both the wild animals, and humans

By analysing video footage of chimps playing, researchers found six key facial movements that are seen in both the wild animals, and humans

TRACKING A CHIMP'S SMILE 

Spontaneous play between two playmates was recorded by a researcher.

A total of 1270 open-mouth faces were identified on the videos, based on the wide parting of the lips. 

They were coded as a single open-mouth face if they had no closed-mouth gaps of 0.5 seconds or longer. 

Some 44 subjects produced 697 open-mouth faces with laughter, 41 subjects produced 573 silent open-mouth faces. 

ChimpFACS analysis was applied to measure the muscle-based movements of open-mouth faces. 

Six actions, that have also been seen in human laughter research, were identified in the chimps. 

These included raising of the upper lips, pulling of the lip corners upwards and backwards, raising of the cheeks, opening of the lips, dropping of the jaw, and stretching of the jaw. 

Marina Davila-Ross, from the University of Portsmouth's Centre for Comparative and Evolutionary Psychology said chimpanzees' communication is more similar to humans than was previously known as they are able to produce these smile types silently without being constrained by the accompanying laughing sound.

She added: '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.'

The researchers filmed 46 chimpanzees at the Chimfunshi Wildlife Orphanage in Zambia and used ChimpFACS - a facial action coding system designed for chimpanzees - to measure their facial movements.

A total of 1270 open-mouth faces were identified on the videos, based on the wide parting of the lips. 

They were coded as a single open-mouth face if they had no closed-mouth gaps of 0.5 seconds or longer. 

Some 44 subjects produced 697 open-mouth faces with laughter, 41 subjects produced 573 silent open-mouth faces. 

Six actions, that have also been seen in human laughter research, were identified across the chimps.  

These included raising of the upper lips, pulling of the lip corners upwards and backwards, raising of the cheeks, opening of the lips, dropping of the jaw, and stretching of the jaw. 

Professor Kim Bard, who designed ChimpFACS, said: 'The coding system allows us to examine very subtle facial movements and compare human and chimpanzee facial expressions, based on their shared musculature.'

By analysing video footage of chimps playing, researchers found six key facial movements that are seen in both the wild animals, and humans. These include raising of the upper lips, pulling of the lip corners upwards and backwards, raising of the cheeks, opening of the lips, dropping of the jaw, and stretching of the jaw 

By analysing video footage of chimps playing, researchers found six key facial movements that are seen in both the wild animals, and humans. These include raising of the upper lips, pulling of the lip corners upwards and backwards, raising of the cheeks, opening of the lips, dropping of the jaw, and stretching of the jaw 

The study investigated specific types of smiles that accompany laugh sounds and found these smile types have the same evolutionary origin as human smiles when they are laughing.

It suggests these smile types of humans must have evolved from positive expressions of ancestral apes.

The study, published in the journal Plos One, further suggests that flexibility in facial expressions was already present in ancestral apes and emerged long before humans evolved.

The researchers filmed 46 chimpanzees at the Chimfunshi Wildlife Orphanage in Zambia (pictured) and used ChimpFACS - a facial action coding system designed for chimpanzees - to measure their facial movements

The researchers filmed 46 chimpanzees at the Chimfunshi Wildlife Orphanage in Zambia (pictured)

Spontaneous play between two playmates was recorded by a researcher (stock image). A total of 1270 open-mouth faces were identified on the videos, based on the wide parting of the lips. Some 44 subjects produced 697 open-mouth faces with laughter, 41 subjects produced 573 silent open-mouth faces

Spontaneous play between two playmates was recorded by a researcher (stock image). A total of 1270 open-mouth faces were identified on the videos, based on the wide parting of the lips. Some 44 subjects produced 697 open-mouth faces with laughter, 41 subjects produced 573 silent open-mouth faces

The researchers then used software called ChimpFACS - a facial action coding system designed for chimpanzees - to measure their facial movements. These images, taken from the ChimpFACS manual, show a subject raising their brows upwards, seen as skin moving over the brow ridge

The researchers then used software called ChimpFACS - a facial action coding system designed for chimpanzees - to measure their facial movements. These images, taken from the ChimpFACS manual, show a subject raising their brows upwards, seen as skin moving over the brow ridge

CHIMPS GET DRUNK - AND KNOW WHEN THEY'RE RIGHT 

Earlier this week, researchers reported that chimps enjoy drinking alcohol.

The creatures, caught on tape in West Africa, held afternoon boozing sessions in palm trees, spending up to half an hour at each supping fermented sap - with the females drinking as much as the males.

And just like us, some of the chimps became tipsy and settled down for a nap straight afterwards.

In a separate study, researchers found that chimpanzees also share another human trait - metacognition. 

During tests, the primates showed they could recognise when they had answered a question correctly, and act on it before being given feedback from the researchers. 

Metacognition refers to when a person is capable of keeping track of what they know and don't know, of seeking information they need to know and they can respond to a question with high confidence or low confidence.

As humans, we are able to verbally report confidence or lack of confidence and use non-verbal behaviours to indicate how sure we are of something, from shoulder shrugs to hesitations.

But the research team wanted to know if other animals show similar behavioural indications of confidence and uncertainty.

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.'

Earlier this week, researchers reported chimps enjoy drinking alcohol.

The creatures, caught on tape in West Africa, held afternoon boozing sessions in palm trees, spending up to half an hour at each supping fermented sap – with the females drinking as much as the males.

And just like us, some of the chimps became tipsy and settled down for a nap straight afterwards.

In a separate study, researchers found that chimpanzees also share another human trait - metacognition. 

During tests, the primates showed they could recognise when they had answered a question correctly, and act on it before being given feedback from the researchers. 

Metacognition refers to when a person is capable of keeping track of what they know and don't know, of seeking information they need to know and they can respond to a question with high confidence or low confidence.

As humans, we are able to verbally report confidence or lack of confidence and use non-verbal behaviours to indicate how sure we are of something, from shoulder shrugs to hesitations.

But the research team wanted to know if other animals show similar behavioural indications of confidence and uncertainty.

The findings are published in the journal Plos One.

Comments (1)

Share what you think

The comments below have not been moderated.

The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline.

We are no longer accepting comments on this article.

Who is this week's top commenter? Find out now