Tuesday, November 06, 2007

New assessment of ape language skills is dramatically scaled back

You've probably heard about all the apes who have been taught to communicate using sign language in recent years. As Mario Beauregard and I discuss in The Spiritual Brain, the discovery that American Sign Language could, in principle, be taught to apes spurred a number of interesting research projects - and some pretty unrealistic claims. In Dragons of Eden (1986), for example, Carl Sagan dreamed of a day when
Although a few years ago it would have seemed the most implausible science fiction, it does not appear to me out of the question that, after a few years in such a verbal chimpanzee community, there might emerge the memoirs of the natural history and mental life of a chimpanzee, published in English or Japanese (with perhaps an “as told to” after the byline).

What you probably DIDN'T hear much about is the mood of skepticism with which much of the science community has greeted this work in recent years - even as the apes impress hosts on national television programs.

In "Aping Language", a thoughtful article in E-Skeptic, Clive Wynne explains how that happened. Wynne certainly does not have a hitch in his craw about the concept of ape language. On the contrary, would have been pleased to discover that apes can be taught grammar. The trouble is, after the initial flurry of success stories, later, more critical research came to the conclusion that they generally can't.

Why did initial reports sound so favourable? One problem was overinterpretation. The ability to learn a large number of signs is not the same thing as the ability to learn a language whose meaning depends largely on grammar. The former achievement is sometimes found among birds as well as mammals, but the latter seems unique to humans.

The ability to string a sequence of words together does not necessarily mean awareness of grammar. The sentence "Tom shot John" does not mean the same thing as "John shot Tom," and the difference is pretty important. Overly generous assumptions were made about the extent to which apes such as Washoe and Kanzi were using grammar. When they were examined by scientists other than their trainers, they did not perform well.

Also, attuned as they were to individual signs of success, researchers were often not looking at the big picture. Reporting on how one researcher revised his thinking after closer study, Wynne notes,
Terrace now argued that Nim's use of ASL signs was quite unlike how children learn language. Nim failed to initiate conversations, he seldom introduced new vocabulary and just imitated what the humans around him said. Nim's sentences failed to grow in length. In human children there is a close relationship between the number of words known and the number of words used in a sentence. Not so in Nim. Throughout his time in the language project he stuck to using one or two words at a time. And his longer utterances were without any regard for grammatical structure. Nim’s longest recorded “sentence” was give orange me give eat orange me eat orange give me eat orange give me you. Not hard to understand — but not very grammatical either.

The key difference between an ape and a child is that the child is growing in intellectual capability. The ape is not. Thus, the ape isn't under any internal pressure to expand his language competence. Once he knows how to satisfy his fairly simple needs, any pressure he experiences will come from drill by humans - at the expense, one suspects, of things he would rather be doing.

Wynne describes his own disillusion,
For a start Kanzi — like Nim before him — did not show the increase in sentence length that is typical of children learning language. In fact, at 1.15 symbols per sentence, Kanzi's average utterance is even shorter than Nim's. And it turns out that to complete many of the requests that were put to him Kanzi did not need to understand grammar. For example when Kanzi was asked to "Take the hat to the colony room" - which Kanzi did successfully - all he needed was some sense of "hat" and of "colony room."

Wynne's point is that, unlike "John shot Tom"/"Tom shot John" the command given to Kanzi is not reversible - a room cannot be taken to a hat. He concludes that, while Kanji's and his trainers' achievements are significant, as far as grammar is concerned, "on any assessment not tinted with rose-colored glasses, Kanzi just doesn’t get it."

Commenting on John Berman's recent Nightline show with 26-year-old Kanzi, he quotes Berman's assessment, "Moments like this are proof that these conversations help scientists learn about apes, from the apes themselves," but says,
I don’t disagree, though I fear the conclusion I draw is not the one Berman intended. Moments like this tell us that Descartes was right, there really are no beasts, no matter how fortunately circumstanced, that can make known their thoughts through language.

As I see it, the take home point is that Kanji doesn't really want anything more out of life than his limited language skills give him. That is what makes all the difference between him and a three-year-old child.

Anyway, it's good to see a magazine that bills itself as "skeptical" living up to its billing by exercising its skepticism in an area that has long been in need of it.

Update: An interesting combox discussion developed on this story over at Uncommon Descent, with some participants claiming that many scientists had never been fooled by the claims. (And, implicitly, shame on me for pointing out how long Sagan-like claims went on being fronted).

I responded to one as follows:

getawitness, it would be scary indeed to think that everyone was fooled. But one Chomsky doesn't alter a pattern that Mario Beauregard and I note in The Spiritual Brain - a very familiar pattern, replicated widely over many issues. The notion that apes can learn grammar was treated as the default "scientific" position in accounts of the subject - even though one did not need a great deal of familiarity with the area to see why it probably wasn't true.

Now, of course, the fact that that was the case - as is demonstrated by the way popular culture sources replicate it to this day - is somehow supposed to fall down a memory hole.

That way, we can avoid disconfirming a materialist prediction.

I for one will work to see that it doesn't fall down a memory hole, but is entered among the disconfirmed materialist predictions.

That will force materialists to redefine their theory so as to exclude what they once enthusiastically included as evidence. Eventually, a paper trail develops ...

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