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Baa-rilliant face recognition

Sheep are able to recognise human faces! Anastasiia Kovalenko explains how scientists made this discovery, and its implications for treating diseases.

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According to new research from scientists at the University of Cambridge, sheep can be trained to recognise human faces from photographs.

Just imagine, eight female Welsh Mountain sheep aged 7-8 years were trained on mugshots of Emma Watson, Jake Gyllenhaal, Barack Obama, and Fiona Bruce. During training, each animal was shown two faces, one of which was a picture of the target celebrity, and the other one either remained blank, displayed an object, or showed a face of an unfamiliar person. If the sheep approached the correct image, it was given an award of food. If it chose the wrong photograph, a buzzer would sound, and the animal would remain unrewarded.

The ability to recognise faces is one of the most important human social skills

Over time, sheep learnt to associate food rewards with target images. After training, in the real study the sheep were shown two images – the celebrity’s face and an unfamiliar face. In this test, sheep correctly chose the learned celebrity face eight times out of ten.

Then, to test how well sheep recognised the faces, the researchers showed them the same celebrities from different angles. During this task, the sheep’s performance dropped, but only by about 15% which is still comparable to that seen when humans perform the task.

Professor Jenny Morton, the lead scientist in the study, said it showed that sheep have “advanced face-recognition abilities, comparable with those of humans and monkeys”.

Flock of sheep. Source: pexels

In animal world, the ability to recognize same-species faces has been shown in many animals, such as dogs, monkeys, goats, pigeons, bees, horses. Horses, dogs and sheep can also distinguish faces of individuals from other species. However, little research has been conducted on recognition of human faces.

In a current study, the researchers also looked at whether sheep were able to recognise a handler from a photograph without pre-training. “Anyone who has spent time working with sheep will know that they are intelligent, individual animals who are able to recognise their handlers,” says Professor Jenny Morton. The handlers typically spent ten hours a week with the sheep. The study revealed that the animals chose the handler’s photograph over the unfamiliar face seven out of ten times. Now what’s interesting about this part of the study is that the sheep demonstrated unusual behaviour: they checked first the unfamiliar face, then the handler’s image, and then the unfamiliar face again before making a decision to choose the handler’s photograph. Professor Morton interprets the sheep’s decisions as “I don’t recognize this photograph, therefore the other one will be familiar”. And when the alternative image also turns out to be novel, the sheep checks the unfamiliar face again, compares it to the novel image of the familiar person, and then makes her decision to choose the familiar person (i.e. the handler’s photograph).

sheep have ‘advanced face-recognition abilities, comparable with those of humans and monkeys’

Wait, but why would they study sheep? Face recognition involves several parts of the brain, and sheep with their large brains and long lives are a good model for studying such human brain problems as Huntington’s disease, Parkinson’s disease, as well as psychiatric disorders such as autism spectrum disorder and schizophrenia. The ability to recognise faces is one of the most important human social skills. We can easily identify familiar and unfamiliar faces from repeatedly presented pictures. However, some of the above-mentioned diseases limit the ability to recognise an unfamiliar face, even after it has been presented several times. Huntington’s disease (HD) affects nearly 7 thousand people in Britain. Some of the earliest symptoms are mood and personality changes, but over time, memory, movement, mental health, speech are affected. There is no known cure for the disease. To shed more light on this topic, the team has now begun studying sheep genetically modified to carry the mutation that causes the Huntington’s disease.

“We can give the sheep new treatments and use our tasks to measure how well they perform over time. We can see how quickly they learn and what they learn,” says Professor Morton. “If a treatment works you would expect to see no difference between a normal sheep and a Huntington’s sheep having the treatment.”

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