Monkeys Pass Mirror Test for Self-Awareness

The website of the University of Wisconsin–Madison has this news item: For first time, monkeys recognize themselves in the mirror, indicating self-awareness. Here are some excerpts, with bold added by us:

Typically, monkeys don’t know what to make of a mirror. They may ignore it or interpret their reflection as another, invading monkey, but they don’t recognize the reflection as their own image. Chimpanzees and people pass this “mark” test — they obviously recognize their own reflection and make funny faces, look at a temporary mark that the scientists have placed on their face or wonder how they got so old and grey.

For background, Wikipedia has a brief article on the mirror test as a measure of self-awareness. They say:

Animals that have passed the mirror test include: all of the great apes (bonobos, chimpanzees, orangutans, humans, and gorillas), bottlenose dolphins, orcas, elephants, and European Magpies. … Dogs, cats, and young human babies all fail the mirror test.

Okay, back to the university’s news article:

Because chimps, our closest relatives, pass the test, while almost all other primate species fail it, scientists began to discuss a “cognitive divide” between the highest primates and the rest.

But a study published today (Sept. 29) by Luis Populin, a professor of anatomy at the University of Wisconsin-Madison, shows that under specific conditions, a rhesus macaque monkey that normally would fail the mark test can still recognize itself in the mirror and perform actions that scientists would expect from animals that are self-aware.

They don’t provide a link, but the article is online: Rhesus Monkeys (Macaca mulatta) Do Recognize Themselves in the Mirror: Implications for the Evolution of Self-Recognition. Let’s read on:

Populin, who studies the neural basis of perception and behavior, had placed head implants on two rhesus macaque monkeys, while preparing to study attention deficit disorder. Then Abigail Rajala, an experienced animal technician who is in the university’s Neuroscience Training Program, mentioned that one of the monkeys could recognize himself in a small mirror. “I told her the scientific literature says they can’t do this,” says Populin, “so we decided to do a simple study.” Much to his delight, it turned out that the graduate student was right.

The news article doesn’t elaborate on the head implants, but the published paper says the test monkeys “had been prepared for electrophysiological recordings with a head implant …” and there’s more information about the implants in the paper’s “Materials and Methods” section. We continue with the news article:

In the standard mark test, a harmless mark is put on the animal’s face, where it can only be seen in a mirror. If the animal stares at the mirror and touches the mark, it is said to be self-aware: It knows that the mirror shows its own reflection, not that of another animal. (Animals that lack self-awareness may, for example, search for the “invading” animal behind the mirror.)


But in Populin’s lab, the monkeys that got the implants were clearly looking in the mirror while examining and grooming their foreheads, near the implant. Tellingly, they were also examining areas on their body, particularly the genitals, that they had never seen before.

Wicked beasts! Then an interesting point is brought up:

Scientists who have used the mark test to explore self-awareness have found the quality in one species of bird, in one individual elephant, and in dolphins and orangutans. And so instead of asking how self-awareness evolved only among primates, they face the larger question of how it evolved multiple times in distantly related species.

But we are left with an even more perplexing question — the Curmudgeon’s Creationist Conundrum: If all the higher apes have a sense of self-awareness, what’s the explanation for creationists’ behavior? If they had the capacity to be aware of how ridiculous they are, surely they’d behave differently.

There’s more information in the university’s news article, so click over there and take a look. And of course there’s much more in the published paper. But there’s no data on our Conundrum.

Copyright © 2010. The Sensuous Curmudgeon. All rights reserved.

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3 responses to “Monkeys Pass Mirror Test for Self-Awareness

  1. So, now we have to say that monkeys are more self-aware than Newt Gingrich?

  2. I am not a great believer in the mirror test. Of my 3 late cats, 2 failed the mirror test, one seemed to pass it. In humans there is considerable variation in intelligence and perception. I see no reason to discount such variability in other animals.

  3. Me too, Thom. Sight is overwhelmingly our most important sense, so we humans give visual stimuli high priority. That doesn’t mean every critter does. To an animal (like a cat) that has a great sense of smell, great hearing, and whiskers and fur to help identify things on their skin, a mirror image may not be that interesting. They know its not real through their other senses. They comprehend, they just don’t care.