Neurophilosophy

Self-recognition was long believed to be unique to humans. However, it was established more than 30 years ago that the great apes are capable of recognizing themselves in the mirror, and more recently it has been found that dolphins and elephants can too.

Now Prior et al provide the first evidence of mirror self-recognition in a non-mammalian species. In this film clip from the supplementary materials which accompany the paper, a magpie (which is actually a female) realizes that it has a mark on the side of its head after seeing its relection in the mirror. It then removes the mark by rubbing its head on the ground, and finally looks in the mirror one more time to make sure the mark has come off:

Birds lack a neocortex, the layered structure which is specific to mammals and which in humans is responsible for everything that we consider unique to our species. But even with their smooth, non-layered brains, birds are still capable of highly complex cognition. The Clarke’s nutcracker has remarkable spatial memory – it can cache nuts in tens of thousands of different locations, and retrieve them all as winter closes in; and crows have tool-making and using abilities that are at least as sophisticated as those of chimpanzees.

Such abilities are associated with a structure in the avian brain called the nidopallium caudolaterale, which corresponds to the mammalian prefrontal cortex not just functionally but also neurochemically (it uses the same, or similar, neurotransmitters). Thus, during their separate evolutionary histories, selective pressure has led to the emergence of complex cognition in both birds and mammals. This is an example of convergent evolution – the same abilities have evolved independently of each other, in two very different groups of organisms with very different brains.

Related:

Prior, H., et al (2008). Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self-Recognition. PLoS Biology 6 (8): e202. DOI: 10.1371/journal.pbio.0060202

Comments

#1 skyotter
August 19, 2008

for some reason i was under the impression that the common raven [C. corax] also passed the paint-mark/mirror test

but as a corvid fan in general: cool! go magpies! =)
#2 Jessica
August 19, 2008

Very interesting. However, I’m getting a message that the video is no longer available.
#3 Mo
August 19, 2008

YouTube is taking forever to process the clip. I can’t think why – it’s just 2Mb in size. It can be downloaded here.
#4 anon
August 19, 2008

Works okay for me.
#5 Michael
August 20, 2008

@skyotter

From “Are corvids �feathered apes�? Cognitive evolution in crows, jays, rooks and jackdaws. In: Watanabe, S (Ed.) Comparative Analysis of Minds (pp. 181-213), Keio University Press: Tokyo” by Nathan Emery:

“Mirror self-recognition (MSR) has been tested in corvids (jungle crows; Corvus macrorhynchos), where the crows were exposed to mirrors in different orientations (horizontal and vertical). The crows aggressively attacked their reflection in the mirror as if a novel, same sex conspecific, therefore not demonstrating any aspect of self-awareness (Kusayama et al, 2000)”
#6 Coturnix
August 20, 2008

If you use plural ‘magpies’ somewhere in your text, it will show up on The Buzz on the front page….
#7 Encefalus
August 20, 2008

I wonder what this tells us for the study of consciousness. Self-recognition at the mirror is a reknowed self-awareness test. Maybe this research will pave the road for neural correlates of consciousness in avians. Certainly, the brain of a bird is simpler than that of a homo sapiens and if they indeed have self-awareness, it would, probably, be simpler to study their brain first.
#8 Jon
August 20, 2008

In my opinion, it is folly to assume that self-awareness, like consciousness, is even a capacity with an unambiguous link to neural correlates, as it is sometimes said. I mean, consciousness could very likely to be an incorrect linguistic attribution that we ourselves learned in our early childhood rather than something that magically arises from some special neural sauce.

However, there is another problem that could potentially be addressed by this: it is impossible to know thoughts based on observations of behaviour. We do indeed draw inferences, and these can stand to reason and extended scrutiny, but a price does get paid for following the folly to the ends of possible understanding when the very function of a brain is hardly given an adequate theoretical framework from which scientists can truly benefit in science’s goal.

Has anyone supposed that all those neocortically endowed beings who failed the test could in fact be fully self-aware and yet did not give a lick to satisfy an expectation in the skull of the scientist? Or, how about the bird wasn’t self-aware at all — but followed a cleaning instinct?

I’m more suspicious of the naive faith in these methods at such an early, terribly early stage in the game.
#9 Josh
August 24, 2008

And yet I still see birds attack their reflections in windows.

But I’d agree that the mirror test is not necessarily the best test for self-awareness, though I’m not sure what would be.