Researchers in Tokyo placed rats in a cage with three compartments . One compartment showed images of rats in pain , and another with neutral faces . Rats spent more time in the ' neutral ' room where they experienced fear . researchers believe facial expressions are used to communicate with others .
Researchers in Tokyo placed rats in a cage with three compartments . One room showed photos of rats in pain , and another with neutral faces . Rats spent more time in the 'neutral ' room suggesting they recognise fear . Experts believe facial expressions are used to communicate with others .