Back in February 2010 I posted a piece about Dr. Con Slobodchikoff’s research into prairie dogs and their language, expressing my deep scepticism. This eventually came to Dr Slobodchikoff’s notice and he posted a comment inviting me to check out his webpage, ‘freely available on Google’ he said, where I would find details of the many peer-reviewed research papers he has published on the subject. Well, I did check out his list of publications, and there are lots of them, but none at all in linguistics. Journals like Behavioural Ecology, Mammology and Intelligent Automation and Soft Computing, are not in any Learning Resources Centre near me, nor are they freely available to people who might want to get hold of them. So I picked a not-too-expensive book, ‘Kinship with Animals’ edited by Solisti and Tobias, in which Dr S. has a chapter about his prairie dog research. Having now read this, I can confidently reaffirm my initial scepticism about them having language. They don’t.
In his chapter Dr S. shows that he has done some homework on the nature and structure of human language, which is only right and proper in anyone claiming to have discovered the same thing in another species. (For this much he deserves credit, for it’s more than Dr Sue Savage-Rumbaugh or Dr Penny Patterson has ever done in their respective research on the language abilities of bonobo chimps and gorillas.) He states rightly that distinctive features of human language are displacement, productivity and duality of patterning. Displacement means that human language can describe not just the here and now, but also things and events distant in time and space. Productivity means that there is literally no limit to what human language can express. Duality of patterning explains how such infinite productivity is possible; a small set of meaningless sounds can be combined in rule-governed ways to make a limitless number of words, phrases, sentences, and so on.
Unfortunately, Dr S. has not understood these features very well. His mistake about displacement is elementary. He takes it to mean the ability to refer to things which are far away, i.e. on the horizon rather than nearby. But this is wrong. Displacement means being able to refer to things which are not discernible, like the dark side of the moon, your lost keys or tomorrow’s headlines. Dogs cannot bark about the cat who came by yesterday, but humans can say the word cat without needing first to see, hear or smell one. Dr S. claims that a prairie dog vocalising about a coyote that was visible on the crest of a hill half a mile away was exhibiting displacement, but until a prairie dog can be proved to be vocalising about the coyote that is too far away to see, hear or smell, or the one that came by yesterday, or the one that might show up tomorrow, no such thing can be claimed. Prairie dog vocalisations are tied to stimuli in the here and now. And this means it is not language.
There is more confusion when it comes to duality of patterning. Here is how Dr S. defines it.
‘A language consists of a duality of structures. The basic units are phonemes which are the smallest units of sound. These phonemes are combined into morphemes, which are the smallest units of meaning. The morphemes are combined into words and the words are combined into sentences.’ (page 65)
Duality of patterning is indeed central to human language. It’s what allows tap, pat and apt to mean different things, and what allows the phrase she has what a man wants to contrast with she wants what a man has: the same units in a different order give a different meaning. Dr S. says this is going on in prairie dog vocalisations, and claims to have discovered the phonemic structures within them. However, phonemes are not physical sounds; they are mental representations of sounds. A phoneme is defined by virtue of the meaningful contrast it is perceived to make with another phoneme. Physically different sounds which do not contrast in a mental representation, such as [r] and [l] for native speakers of Japanese, or [p] and [b] for native speakers of Arabic, are not separate phonemes but allophones of the same phoneme. So you cannot discover phonemes in a recording of prairie dog whistles by slicing the acoustic signal up into little time segments and looking to see physical differences, which is what Dr S. has done. Moreover, anyone who claims to have identified phonemes should be able to demonstrate what the contrastive units are, which Dr S has not done, at least not in this book.
Duality of patterning is the driver of productivity in human language. The possible set of combinations of phonemes into words and words into sentences is prodigiously large, infinite even. Any novel thing we encounter can be labelled with a new word, or described by a novel combination of old words. So Dr S. is not modest in his claims. The existence of phonemes in prairie dog vocalisations means, he says, that there is duality of patterning, and by extension there must be an underlying syntax governing the combinations of phonemes in different calls, and by further extension, there is productivity in expression. He says that the prairie dogs in his study could produce warnings about ‘new objects they had never seen before.’ (page 70). His experiments however, (as least as described here) are unconvincing. The one on page 69 is particularly weak. He showed a colony of prairie dogs a black oval shape travelling on a wire past their burrows, reasoning that this would be an entirely novel thing in their experience. All the prairie dogs who saw the oval made the same new alarm call. Dr. S concludes that all the animals had made up the same new word (sic) for ‘black oval’; evidence, he says, of productivity in their language. It does not occur to him that it is spectacularly unlikely, given the large number of possible combinations their ‘phonemes’ can supply, that all the individuals would come up with the same novel combination. Nor does it occur to him that the vocalisation sparked by the black oval was new to him rather than to them, and it did not ‘mean’ black oval, but was a shared instinctive call roughly translatable as ‘God knows what that is, but it scares the hell out of me.’
Dr S. goes even further in speculating about the type of prairie dog vocalisations known as social chatters.
‘Do these chatters contain any meaningful (sic) information that one prairie dog conveys to another? We don’t know. We don’t have a key, a Rosetta stone, to decipher these calls. They could be simply expressions of the internal mood of each prairie dog, communicating no meaningful (sic) information. Or they could be comments on how beautiful the day is.’ (page 71)
Given that Dr. S has just claimed to have found evidence of at least nine ‘words’ in such chatters plus evidence that the words are always ordered in a rule-governed way, we can conclude that he believes nature has not wasted time and effort evolving a complex, hierarchical and rule-governed vocalisation system in the prairie dog just to express private internal moods. And indeed his research continues to search for the key that will unlock what they are saying to each other. (Though as any linguist would point out, the set of phonemes Dr S. claims to have identified for prairie dog language is pretty much the Rosetta stone he says he doesn’t have.) Meanwhile, let us consider for a moment how a prairie dog could even begin to conceptualise a beautiful day.
The arguments for the existence of a language system in a non-human species always begin by taking human language as a yardstick and seeing how far the other species matches up to it. There is an underlying assumption in this kind of research that we are somehow diminishing animals if we conclude that humans have something they lack. This is daft in my opinion, but it explains why researchers looking for humanlike language nearly always find it, even when they have to stretch definitions to the breaking point and delude themselves in the process. I do not understand why animals need to be seen to measure up to humans in order to gain our respect. I do not understand why so many of the chapters in ‘Kinship with Animals’ take the line that someone who denies that animals are ‘just like us’ necessarily hates them, or wants to kill them, destroy their habitat, or otherwise abuse them. I like prairie dogs, I am appalled by the way urban development is encroaching on their environment (which I saw with my own eyes last year in Denver), and I would never, ever, harm one. But they don’t have or need language. I am sure of that.
(If you have read any of this, Dr S, I hope you take it all in the spirit of constructive criticism which should inform scientific debate. It seems to me that you need a linguist’s viewpoint if you are going to make claims about language, and I hope it helps you make your case more robustly.)