Mirror Mirror

AN ARTICLE FROM: WWW.AFRICANATURE.COM

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MIRROR, MIRROR, ON THE WALL
By Barbara Katz

One of the most common toys bird owners purchase is a mirror. Parakeets, cockatiels, parrots and others seem to respond to their reflections. Or do they? Does the bird merely peck at an object that just happens to be a mirror? Does the bird bob its head in front of the mirror because it’s excited to see its own reflection? Does the bird push the mirror because it thinks the image is another bird, another rival? Exactly what is happening to an image in the mirror?

KYAARO AND ALO STUDY THE MIRROR

Dr. Irene Pepperberg has investigated how Greys respond to and use mirrors. Her study subjects for this research were Alo (who has since gone to live with another researcher) and Kyaaro. Alex could not participate in the experiments because, long before this project was initiated, he had essentially been taught that the image he saw in the mirror was "Alex." Students, looking for ways to entertain him, would let him look into the mirror and ask, "Who’s that?" Then they answered the question for him, "That’s Alex." Dr. Pepperberg needed to find out what the birds could learn on their own from interactions with mirrors.

The information in this article only highlights the main points of the study. For further details, readers might want to read the full report, "Mirror Use in African Grey Parrots [Psittacus Erithacus]" in the Journal of Comparative Psychology, 1995. All the experiments required a brief period of habituation for the birds: they were given a chance to adapt to the experimental design, but the data from those trials were not included in the final results. Some tests used familiar objects and others used novel, or new items.

MIRROR IMAGE STIMULATION

Experiment Number 1 was Mirror Image Stimulation (MIS) in which the subject is allowed to view its entire body. This simple procedure is often used to determine whether a subject has any self-recognition. For animals who often use hearing and smell to guide their actions, MIS tests the extent to which visual cues alone determine behavior.

A mirror, approximately 22" by 15" in a brown plastic frame was placed on a counter. Alo and Kyaaro could wander freely about the countertop. The mirror was usually in the vertical position. However, for two trials the mirror was placed flat on the counter so the birds could walk on it, and during four other trials, the mirror was put in an open drawer so they could look down at their reflections.

Alo and Kyaaro’s reactions spanned a range of behaviors; but their responses indicated that they most likely interpreted the mirror image as another bird. They tapped the mirror with their beaks; but their bills were open as they are when they engage in "beak wrestling" with each other or Alex. They bent their heads toward the mirror image. Alo and Kyaaro (and Alex) use this posture to solicit preening from each other and people in the lab. Kyaaro said "you come" and "tickle." It’s possible he was talking to the trainer who was taking notes but it seemed to be directed at the mirror (another parrot). Those phrases are also commonly heard when the birds are alone in their rooms. Alo sometimes talked to the mirror when she heard voices outside her room, but only once did she initiate vocalization. Of course, when she did this, the mirror (i.e. the other parrot) did not respond. Every parrot owner knows that talking, singing, etc.. to your bird elicits social interactions and vocal responses. In the absence of any such response from the image, Alo lost interest in talking to the mirror.

Both Alo and Kyaaro were more aggressive toward the image when the mirror was in the vertical, rather than the horizontal, position. A vertical image image more closely resembles another bird and thus Alo and Kyaaro’s aggression may have been directed at the "intruder." The horizontal image may resemble what they had already seen on the bottom of the lab’s stainless steel sinks: their own reflections. It also stimulates what a wild parrot may experience: a reflection in a pool of water.

Lastly, both birds looked behind the mirror. Kyaaro, the younger bird, performed this action frequently. According to Dr. Pepperberg, "Such behavior is common in subjects who do not demonstrate mirror self-recognition."

She further concluded, "Their behavior patterns also suggested that they might engage in mirror-mediated object discrimination and reaching: when the mirror was placed under a counter in an open drawer so that they could look down to review their reflections, they both looked under and explored the hidden counter edge. We thus decided to examine Mirror-Mediated Object Discrimination (MMOD) and Mirror-Mediated Spatial Locating (MMSL).

MIRROR-MEDIATED OBJECT DISCRIMINATION

Experiment Number 2, Mirror-Mediated Object Discrimination, tested whether the birds could use a reflected image to distinguish between positive and negative items (e.g. food versus an undesirable toy or something scarey). Would they retrieve the good item and move away from the bad item?

An open-ended box was placed on the countertop, either parallel or at a 45 degree angle to the mirror at a distance of about twelve inches. The birds could only see the object within the box by using the mirror.

Alo nearly always went toward and looked in the box, after viewing a positive stimulus (scores ranged from 18 of 20 to 20 of 20); and she moved away from the box in the presence of negative stimuli (score range: 16 of 20 to 19 of 20). It didn’t matter whether the box was parallel to the mirror or at an angle. She clearly used the mirror to guide her behavior.

Kyaaro required two sets of trials. He became accustomed to the original negative items and they no longer made him the least bit apprehensive. When Dr. Pepperberg used a small towel as a negative item, Kyaaro’s test results were comparable to Alo’s. (The towel is used to restrain Kyaaro during medical treatments.)

MIRROR-MEDIATED SPATIAL LOCATING

Experiment Number 3, Mirror-Mediated Spatial Locating, tests whether birds use mirrors to find items placed in hidden locations. The set-up for these tests used an open drawer beneath the countertop. The bottom surface of the counter that overhangs the rear portion of the partially opened drawer was divided into three, and sometimes four, sections with pieces of posterboard flushed against the counter’s underside. Then the mirror was put in the drawer so that it reflected the underside of the counter. Only by using the mirror could the birds view the object hidden in a section. They could only view one section at a time.

For additional trials, Dr. Pepperberg placed mirrors on the wall above the counter that reflected the contents of eight compartments. These sections were behind a barrier so that, again, the birds could view the contents only by using the mirrors.

Both Alo and Kyaaro used the mirrors to locate the hidden objects (all of which were positive items or else the birds would not have wanted to find them). They failed to search in trials in which the mirror was absent. But although the data are convincing, they are not conclusive. Did they use the mirror simply as a cue to begin a search? Or did they understand that there was no sense in searching without the mirror? The latter requires information processing.

The results from the MMOD experiment, however, suggest that the birds do not use the mirror simply as a cue. They indeed realize the mirror is reflecting an image of a real object. If they didn’t, during MMOD they would not have differentiated positive from negative items and refrained from searching when the latter were present; they simply would have searched on every trial.

Dr. Pepperberg is continuing to investigate the subject of mirror use by African Grey Parrots. The matter of self-recognition is also under further study. The classic test for self-recognition is difficult to conduct on parrots. It involves putting a colored mark on a part of the subject’s body that it cannot see without the use of a mirror. If the subject looks at its reflection and touches the mark on its body, instead of the mirror image, it has demonstrated that it knows the image in the mirror is a reflection of itself. Because of a parrot’s eye placement, there aren’t many parts of its body that it cannot see.

Barbara Katz has known Dr. Pepperberg for many years and writes about the work on Alex for THE GREY PLAY ROUND TABLE, a magazine on Grey Parrots. If you wish to learn more about Alex, please refer to: http://www.cages.org/research/pepperberg/index.html If you wish to learn more about Grey Parrots, refer to: www.africangreys.com