Humans and monkeys can now extend a warm welcome to sheep for joining us in being able to recognize human faces from photographs.
Researchers at the University of Cambridge trained eight sheep to recognize the faces of four celebrities from photos shown on a computer screen. Those celebrities were journalist Fiona Bruce, actor Jake Gyllenhaal, former US President Barack Obama and actress Emma Watson.
For the initial training, the sheep received a food reward for choosing the face versus a blank screen. Then, the researchers showed the sheep two different face photos and gave it a food reward for choosing the correct face it had learned before. The sheep chose the right face eight out of 10 times.
The sheep were also able to recognize the celebrity faces when the person's head was at an angle rather than just straight on, though the scientists noted a drop in performance "of a magnitude similar to that seen when humans perform this task."
The woolly creatures could reliably pick out their human handlers without any previous photographic training at all, showing they can spot a familiar face.
Neurobiology professor and study lead Jenny Morton says, "Sheep are long-lived and have brains that are similar in size and complexity to those of some monkeys."
Morton is using sheep as models for studying human brain disorders. The photo recognition experiment gives scientists a way to track changes in the cognitive abilities of sheep with a gene mutation that causes Huntington's disease, an incurable neurodegenerative disease.
The researchers published their findings today in the Royal Society Open Science journal with the title "Sheep recognize familiar and unfamiliar human faces from two-dimensional images."