With eye-catching headlines such as “Ewe again” and “Don’t I recognise ewe?” what really is behind the story that was all over the news last week? Why were researchers training sheep to identify the faces of actors Jake Gyllenhaal and Emma Watson, former US President Barack Obama and BBC newsreader Fiona Bruce? Recent research carried out at the University of Cambridge has shown that sheep are not as stupid as we are often led to believe!
The ability to recognise faces is an important social skill in humans. While the exact nature of the processes involved are not fully understood it is widely accepted that face perception involves extensive and diverse areas of the brain. In humans, faces are processed holistically – our visual system recognises a face as an integrated whole rather than as a collection of separate facial features.
Holistic processing is often used as the basis for explaining how we identify people (i.e., recognize someone that we know or have seen before). Evidence suggests that it might also apply to other aspects of facial perception, such as ‘reading’ emotional expressions or attractiveness. Researchers at Cambridge University have found that sheep have advanced face-recognition abilities, similar to those of humans and other primates.
In a study that employed an operant learning system (think Pavlov’s dogs), researchers investigated cross-species face-recognition abilities in female Welsh Mountain sheep. Results from the experiment show that sheep can learn to:
- Discriminate faces from other objects by recognising facial features;
- Recognise the faces of unfamiliar individuals from a different species (i.e., humans) in photographs;
- Identify these unfamiliar individuals when shown images of these individuals from different perspectives;
- Recognise the face of a familiar person that they encounter in ‘real life’ (e.g. handler) from a 2-dimensional image.
The findings support the idea that sheep have complex image processing abilities including holistic face-recognition skills and the ability to convert 3-dimensional information to 2- dimensional information. While this may come as no surprise to people that work with sheep every day, it could have important implications for extending our understanding about animal welfare and neurological disease in humans.
Face-recognition and processing have been linked to the identification of ‘self’ and other cognitive processes such as ‘reading’ emotions. The findings from this research raise new questions about the ability of sheep to identify emotional expressions on human faces and subsequent behavioural responses. Research into this area could provide valuable insights into questions around animal welfare on the farm and beyond the farm gate.
The fact that sheep have been trained to recognise famous actors and past US presidents certainly makes for an eye-catching headline. But the insights provided by these findings also offer opportunities to extend research into areas of cognitive disfunction where face perception and the recognition of emotional expressions are impaired, for example, as a result of neurogenerative disease (e.g. Parkinson’s and Huntingdon’s disease) and psychiatric disorders (e.g. autism spectrum disorder). These opportunities are made even more possible with the recent development of a transgenic sheep that shows similar brain pathology to individuals who suffer from Huntingdon’s Disease which could, therefore, be used as a model for future investigation.
The research is published in the Royal Society’s Journal, Open Science