Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

For First Time, Monkeys Recognize Themselves in the Mirror, Indicating Self-Awareness

30.09.2010
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 40 years, scientists have concluded from this type of behavior that a few species are self-aware — they recognize the boundaries between themselves and the physical world.

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.

The finding casts doubt on both the relevance of the mark test and on the existence of a definitive cognitive divide between higher and lower primates.

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.

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.)

Rhesus macaques, a mainstay of medical and psychological research, have long failed the mark test.

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. In some cases, the monkeys even turned themselves upside down during these examinations. In other cases, they grasped and adjusted the mirror to get a better view of themselves.

When the researchers covered the mirror glass with black plastic, these behaviors disappeared, and the monkeys ignored what had been a subject of fascination.

Furthermore, although a macaque will often interpret its reflection as representing an intruding monkey and adopt either an aggressive or submissive response, the implanted monkeys showed dramatically fewer of those “social” behaviors compared to the behaviors, such as exploring hidden body parts, that indicate self-awareness, Populin says.

“This report makes a unique contribution to our views about primate self-awareness because the ‘mirror test’ has been the traditional gold standard for determining if a person and/or animal met a criterion for having a sense of self,” says Christopher Coe, a primatologist and professor of psychology at UW-Madison. “If a young child, brain-damaged adult or animal was able to recognize and appreciate that the image in the reflection was really them, then it was interpreted as proof of being aware.”

Thus, Coe says, “If we follow that logic through with the belief that mirror recognition is proof of a sense of self, then we need to extend that attribute at least to rhesus monkeys.”

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.

The study may refine how the mark test is used, Populin says. “We clearly have data showing that these animals recognize themselves in the mirror, but fail the mark test.”

The mounting data on self-awareness has undermined the concept of a cognitive divide in the primate lineage, Populin says. “There is another idea in primatology, and Charles Snowdon of UW-Madison has contributed to this, that instead of a divide, self-awareness has evolved along a continuum, so we will find it in different forms in different locations on the tree of evolution. I think the mark test may not be sensitive enough to detect self-awareness in the lower species; they may have it, but in a different form, and it may show up in different situations, using different tests.”

Luis C. Populin | Newswise Science News
Further information:
http://dx.plos.org/10.1371/journal.pone.0012865
http://www.news.wisc.edu/newsphotos/macaque-mirror.html

Further reports about: Populin mirror mirror test monkeys rhesus macaque self-awareness

More articles from Studies and Analyses:

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>