The mirror test is essentially a test of self-recognition. Put a smudge of soot on a baby’s nose and then plonk them in front of a mirror. Until the age of 18 months or so, the baby will be none the wiser. They can’t identify their reflection and so don’t think the soot is odd.
Now repeat the exercise with a two-year-old (but good luck getting them to sit still). Most children of this age will touch the dirty mark, which psychologists interpret as a sign, not just that the child can recognise its image, but that it is becoming self-aware.
The test was devised in 1970 by American psychologist Gordon Gallup Jr, who wanted to see if animals could recognise themselves. Since then, many animals have taken the test, but only a few have passed. These include great apes, killer whales, bottlenose dolphins, Eurasian magpies, a fish called the cleaner wrasse and an Asian elephant.
Animals that have failed the test include giant pandas, sea lions, parrots, New Caledonian crows, various macaques… and cats and dogs.
Dogs rely heavily on their sense of smell, so critics argue that the mirror test is unfair to dogs. A better experiment is to collect fresh urine samples from your dog and several others, and then monitor your dog’s reactions to them.
Researchers have found, not just that dogs can discriminate their own odour from that of other dogs, but that when that odour is tainted with an additional smell – analogous to when the babies’ faces are tainted with soot – they spend more time sniffing it. This suggests that dogs can recognise themselves after all.
As for cats? Good luck persuading them to do anything even remotely acquiescent!
Read more:
- Do dogs recognise their own breeds?
- Adults’ brains grow too, and it may help them recognise faces
- How do animals recognise other members of their own species?
- How do fish know who they are?
Asked by: Elliot Savage, Derby
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