Vanity may not be just a human trait after all.
Just like humans and great apes, rhesus monkeys can recognise themselves in a mirror. New research from Shanghai’s Chinese Academy of Sciences shows that, although monkeys do not initially recognise their own reflections, they can learn to do so.
Lead researcher Gong Neng says it is the first time monkeys have passed this important hallmark test of higher cognition.
“We paint a dye on the monkey’s face, which is undetectable and odourless. The monkey doesn’t know that the colour exists. But the monkey can see it when it looks in the mirror. Just like us humans, when I see my face is quite dirty in the mirror, I will use my hands to explore the dirt on my face,” he said.
Several tests were used on the rhesus monkeys, including shining a red laser light or placing a dye-mark on their face that could only be seen in a mirror.
After two to five weeks of tests with food rewards, the monkeys learned to touch the laser dot or dye mark on their face while looking in the mirror, indicating self-recognition.
Understanding the neural basis of self-awareness and consciousness is the ultimate goal of understanding the human brain, according to the team, which hopes that the findings could eventually be used in therapy to help people who have lost the ability to recognise themselves in the mirror.
“Clinically, one fifth of children with autism cannot recognise themselves in the mirror. In addition, adults with mental disabilities and illness or dementia also have difficulty recognising themselves. So our research offers a method that might help them regain this ability. But there is still a long way to go in this field of research,” says Professor Gong Neng.
Some of the monkeys even used the mirrors to inspect body parts that they normally can’t see. While the study is not conclusive and some of the monkeys failed to pass the recognition test, it does however offer plenty to reflect on.