Mice and monkeys share revealing facial expressions

Research from Germany has discovered that facial expressions in mice and macaques can be used to measure cognitive states and understand thought processes — a potential breakthrough for brain research. 

Scientists at EARA member Ernst Strüngmann Institute designed a virtual reality environment and had macaques and mice perform a natural task — searching for food — which is largely influenced by internal cognitive states such as attention and motivation.  

The researchers recorded the animals’ facial expressions and used a statistical model and computer simulations to identify expressions that could accurately predict when the animals would respond to challenges and how well they would solve the search task. 

They found that each cognitive state corresponded to a specific facial expression identified in both mice and macaques. “This means that facial expressions can be considered a reliable manifestation of internal cognitive states even across species boundaries,” said Alejandro Tlaie Boria, first author of the study published in Nature Communications. 

After investigating if this also occurs in humans, these findings could become relevant for applications in psychiatry and in autism and dementia research, for example, to recognise latent cognitive states in non-verbal individuals or for improving ADHD diagnostics.