Human Or Animal?

by Michael Bell

Well, are we like animals or aren't we? Of course, we are animals, anyway, but everyone intuitively accepts that we humans are somehow 'special', so that the question is readily understood. The last 150 years has seen a gradual reduction of the list of differences between humans and other animals, and every day now seems to bring a new discovery of some feature of the brain or the body which, sometimes surprisingly, we find we have in common with some other species, or many of them.

But the argument between the 'likes' and the 'unlikes' (I almost want to call them dualists) will not go away, and is well illustrated by two pieces of research which were published this week.

'What is it that distinguishes humans from other mammals? The answer to this question lies in the neocortex ? the part of the brain responsible for sensory perceptions, conscious thought, and language. Humans have a considerably larger neocortex than other mammals, making it an ideal subject for the research of higher cognition.' Thus speaks a dualist in Science Daily, reporting on research on the functioning of cortical 'chandelier' cells (Molnár G, Oláh S, Komlósi G, Füle M, Szabadics J, et al. (2008) Complex events initiated by individual spikes in the human cerebral cortex. PLoS Biol 6(9): e222. doi:10.1371/journal.pbio.0060222).

The authors triggered specific chandelier cells, causing a sequence of electrical events in the neocortex. They found that the synaptic pathways between chandeliers and pyramidal cells are extremely strong ? much stronger than has been recorded previously in other mammals. This, say the authors, suggests that humans do possess different types of cells, and that our higher cognition isn't due to having larger cells.

Meanwhile, at the Great Ape Trust, a peer-reviewed paper by Janni Pedersen, an Iowa State University Ph.D. candidate from Denmark, analyzed a videotaped conversation between the bonobo Panbanisha and Dr. Sue Savage-Rumbaugh, now a scientist with special standing at Great Ape Trust, but a researcher at Georgia State University's Language Research Center when the video was made about 15 years ago.

Language-competent bonobos use lexigrams, which are made up of arbitrary symbols that represent words, as the basis for conversations with humans. In the video, Panbanisha was in the forest with Savage-Rumbaugh and an assistant, who had a dog in tow that Panbanisha didn't like. Panbanisha repeatedly used the lexigrams to ask to be carried by the assistant. Savage-Rumbaugh offered other resolutions, but Panbanisha remained firm.

Pedersen said linguistic aspects of the conversation included turn taking, negotiation, pauses and repetition, and went far beyond information sharing made possible through the use of lexigrams symbols. "She was using language to get at what she wanted," Pedersen said. "She is very, very clever and is fully capable of following the conversation the same way a human does. This tells me that Panbanisha's knowledge of language is far beyond understanding the words, to understanding how to use them in a conversation to get what she wants."

William M. Fields, director of bonobo research at Great Ape Trust, says the publication opens an important new chapter in the debate about the linguistic capabilities of apes. "The resistance to this in the scientific community is enormous," he said. "For the first time, we have a student who is using linguistic tools that have normally been applied to humans now being applied to non-humans. This is a move toward using the kinds of methodology that are appropriate in ape language, based on Savage-Rumbaugh's 1993 monograph, Language Comprehension in Ape and Child."

"One of the things Janni has affirmed, and affirmed in a way the lay person can understand, is the aspect of turn-taking. If there is anything universal in human language, it's turn of talk," Fields said. "The fact that Panbanisha has done this, and it's accessible even to an untrained reviewer, I think is an important aspect of her paper. She has looked at the whole social action, and the meaning. Ideational flow ? going back and forth ? is obvious.

"Originally, repetition was thought of as something that happens normally in human language," he said. "Traditionally, repetition in ape communicative behaviors is assumed to be proof that they don't have language. It's a kind of dichotomy or unfairness."

I'd like to know about Panbanisha's chandelier cells . . .



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