The Mirror Test

Two chairs

Something looks in a mirror and touches a mark on its own face. One chair says that is self-recognition. The other says it is a mark being touched.

The question

In 1970 the psychologist Gordon Gallup put a mark on the brow of a sleeping chimpanzee and later gave it a mirror. It looked, then reached for its own brow. Passing that test became the standard sign of self-recognition. Machines can pass it now. Does passing mean anything?

Round 1

The chair that trusts the testA creature that uses a reflection to find a mark on its own body has linked the image to itself. Chimpanzees, orangutans, dolphins, an Asian elephant and magpies have done it.

The chair that doubts itIn 2019 a small reef fish, the cleaner wrasse, passed. Either a fish recognises itself, or the test picks out something narrower — noticing a mark and trying to scrape it off.

Round 2

The chair that trusts the testFailing proves nothing: dogs fail a visual test and may know themselves by smell. But passing still shows that something is tracking its own body from the outside.

The chair that doubts itA robot can be built to pass: see motion in the mirror that matches its own commands, conclude “that is me.” A few lines of code, and no one home.

Round 3

The chair that trusts the testThen the machine is the interesting case. If matching your own movement to an image is all it takes, perhaps that is most of what we do too.

The chair that doubts itOr the test was only ever a doorway — a thing to check before asking the real question, which no mirror can ask for you.

Where are you sitting?

The chair that trusts the test The chair that doubts it Neither — I’m still listening

Held open

The mirror test is a good question about bodies and a weak one about minds. It shows something can use an image to find itself. Whether anyone is there to be found is a second question, which a mirror cannot answer.

Look at the reflection. Then ask who is asking.

scroll to hear both

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