Birds and the number 0

I’ve been working on an article that has me thinking about neuroscientifc studies on the cerebral representations of magnitude and it happened to be brought to my attention today that Irene Pepperberg spoke at the 2012 Francis Crick Memorial Conference on Consciousness in Animals.

Pepperberg is famous for having worked for many years with an African gray parrot who appeared to be able to understand concepts such as ‘bigger,’ ‘different,’ ‘same,’ numerals 1 to 6, the names of colors, and he could speak his answers to questions.  The famous bird’s name was Alex and I didn’t know anything about him until today.  During her talk at the conference (which is available on their website) I heard the story of when Alex used to word “none” to mean zero things. Pepperberg pointed out that it was a use of the word “none” that he hadn’t been taught.  Brandeis University reported on this event in 2005.

Strikingly, Alex, the 28-year-old parrot who lives in a Brandeis lab run by comparative psychologist and cognitive scientist Dr. Irene Pepperberg, spontaneously and correctly used the label “none” during a testing session of his counting skills to describe an absence of a numerical quantity on a tray.  This discovery prompted a series of trials in which Alex consistently demonstrated the ability to identify zero quantity by saying the label “none.”

In a NY Times story, written 10 days after the bird died in 2007, the scene is more fully described:

A bigger leap came in an experiment about numbers, in which the parrot was shown groups of two, three and six objects.  The objects within each set were colored identically, and Alex was asked, “What color three?”

“Five,” he replied perversely (he was having a bad attitude day), repeating the answer until the experimenter finally asked, “O.K., Alex, tell me, “What color five?”

“None,” the parrot said.

Bingo.  There was no group of five on the tray.

Alex had previously used the label “none” to when asked to describe the similarity or difference between two objects where there was none.  But he had never been taught to use it to represent zero quantity.

Pepperberg’s work with Alex contributes to the growing evidence that, although the avian brain is different from the mammalian cortex, it is capable of higher order cognitive processing.  For me, the significance of observations like these is not simply that they change our ideas about animal consciousness, but that in so doing, they demonstrate, in unexpected ways, that meaning is not something superimposed on sensory processes, but rather something that emerges from within them.   It makes a different kind of sense that mathematics is one of the keys to human culture if mathematics is seen as something that actually grows out of some very fundamental cognitive processes.  It brings to mind some of the work I have read belonging to José Ferreirós, philosopher and historian of math and science. I find his take on the development of modern mathematics very ‘cognitively’ oriented.   He’s written often about the significance of Riemann’s nineteenth century work and, in one of his papers, suggests that Riemann’s conceptual approach to mathematics is actually more consistent with current views of biological and cultural evolution than the more traditional views held by many of his contemporaries.   According to Ferreirós, for Riemann,


…all knowledge arises from the interplay of  “experience” broadly conceived (Erfahrung) and “refection” in the sense of reconceiving and rethinking (Nachdenken); it begins in everyday experiences and proceeds to propose conceptual systems which aim to clarify experience going beyond the surface of appearances.  Reason in the old sense is found nowhere…


An interesting note about the conference is that participants signed what they have named The Cambridge Declaration on Consciousness in Non-Human Animals.  The full text of the declaration can also be found on the website.  One of the points of the declaration was this:


Birds appear to offer, in their behavior, neurophysiology, and neuroanatomy a striking case of parallel evolution of consciousness.  Evidence of near human-like levels of consciousness has been most dramatically observed in African grey parrots.  Mammalian and avian emotional networks and cognitive microcircuitries appear to be far more homologous than previously thought.  Moreover, certain species of birds have been found to exhibit neural sleep patterns similar to those of mammals, including REM sleep and, as was demonstrated in zebra finches, neurophysiological patterns, previously thought to require a mammalian neocortex.  Magpies in particular have been shown to exhibit striking similarities to humans, great apes, dolphins, and elephants in studies of mirror self-recognition.


1 comment to Birds and the number 0

  • david pinto

    The fact it is ‘none’ is interesting. In a way, none is easier, perhaps. To use the same term to describe ‘two’ apples and ‘two’ bananas is one thing, since the term abstracts across a range of phenomena. I wonder if the bird could count all things it was not familiar with, and what answer it came up when the water of one glass was poured into the water of another. I am guessing that ‘none’ apples and ‘none’ bananas are easier, because as animals we are aware when there is no more food, or the absence of something we ‘expect’. The point is, there is no abstract term to apply to a range of visual phenomena, just a term to apply to the absence of them, whatever they may be. The way to test it is to teach parrots none before the other numbers perhaps. Or it may be easier to teach a child none than it is start with one, two, three, etc?

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