Sheep, on average, chose the celebrity faces correctly in 8 out of 10 trials.
Researchers at the University of Cambridge trained eight sheep to recognize the faces of four celebrities from photos shown on a computer screen. A celebrity's face would appear on one screen, while a different image appeared on the other.
Sheep join the small group of animals shown to recognize human faces, including monkeys, dogs and horses.
A sheep "model" of Huntington's disease has been bred, displaying similar brain and social changes as witnessed in human patients. Then, during the trials, the sheep were released into a pen where they had to discern between the familiar faces and an object or an unfamiliar face. "I guess they have extended our work to show that sheep generalize viewpoints of the faces, which does require a rich representation of the identity". The sheep didn't do as well but still passed, recognizing the celebrities about 68 percent of the time - a drop in performance comparable to that seen in humans performing the same task. The sheep were still able to choose the correct person, showing that they weren't simply memorizing what a 2D photo looks like, but instead were understanding the 3D idea of a human head. The sheep were given food to create an association.
In a final test, the sheep had to choose between a picture of one of their handlers' faces and an unfamiliar face. "That says to me that identity is important". Maybe they just didn't like that the non-familiar lacked a reward, for example. "Sheep recognise Obama from photo".
"We can't say for sure that the sheep understand that the pictures represent humans".
The study feeds into ongoing research on treating neurodegenerative diseases such as Huntington's, in which face perception can be impaired. "Finally, after 10 years of development, we now have a really useful battery of tests we can use to measure cognitive function in sheep".