Symbols, Language and Human Uniqueness

David Premack wrote an interesting perspective piece in the January 2004 issue of Science concerning the uniqueness of human cognition, as distinct from other primates, with regard to our use of symbols. Before debating his perspective, I'll review it in detail.

According to Premack, six symbol systems are in use by humans: the genetic code, spoken language, written language, arabic numerals, music notation, labanotation (a choreography coding scheme, oddly). Premack suggests that the first two "evolved" whereas the last four were invented. The rest of his article concerns the extent to which our use of symbols is unique in the animal kingdom. The authors identifies six ways in which human symbol use is unique, discussed in brief below:
  • Voluntary Control of Motor Behavior. Premack argues that because both vocalization and facial expression are largely involuntary in the chimpanzee, they are incapable of developing a symbol system like speech or sign language.
  • Imitation. Because chimpanzees can only imitate an actor's actions on an object, but not the actions in the absence of the object that was acted upon, Premack suggests that language cannot evolve.
  • Teaching. Premack claims that teaching behaviors are strictly human, defining teaching as "reverse imitation" - in which a model actor observes and corrects an imitator.
  • Theory of Mind. Chimps can ascribe goals to others' actions, but Premack suggests these attributions are limited in recursion (i.e., no "I think you thought he would have thought that.") Premack states that because recursion is a necessary component of human language, and because all other animals lack recursion, they cannot possibly evolve human language.
  • Grammar. Not only do chimps use nonrecursive grammars, they also use only words that are grounded in sensory experience - according to Premack, all attempts have failed to train chimps to use words with meanings grounded in metaphor rather than sensory experience.
  • Intelligence. Here Premack suggests that the uniquely human characteristics of language are supported by human intelligence. Our capacity to flexibly recombine pieces of sensory experience supports language, while the relative lack of such flexibility in other animals precludes them from using human-language like symbol systems.
Unfortunately, this cross-species comparison of symbolic systems seems flawed for a few reasons:
  1. There is no established test for what makes a given action voluntary, and so we cannot know that animal motor acts are truly involuntary.
  2. Voluntariness is irrelevant to the question of language. For example, if I am drunk out of my mind, and I involuntarily blurt out a recursive, grammatical and metaphorical verbalization, it is still human language, despite being involuntary.
  3. Imitation in the absence of an acted-upon object is also irrelevant to the question of language. Language is purely symbolic, meaning that it does not directly act upon anything, and so it's unclear why the physical circumstances of imitation should be so important.
  4. If one insists that physical imitation skills are critically relevant, Premack's claims still contradict evidence reviewed here suggesting that primates are capable of symbolic play without human instruction. And then there's some remarkable work from the Brazilian rainforest showing how primitive some human symbol use is.
  5. Teaching (even using Premack's narrow definition) is not a strictly human behavior: consider this evidence, reviewed by John Hawks, that meerkats modify the behavior of their errant meerkat pupils. Yet, as far as we know, meerkats do not have a human-like symbolic system. Thus, teaching of this sort seems irrelevant to the evolution of language.
The other sections have their flaws as well, but none as critical as those laid out above. Still other vagaries are more philosophical in nature, and often completely immaterial to Premack's point: for example, how to distinguish symbols that evolved from those that were invented?

In summary, it seems like Premack has simply asked the wrong question. Instead of asking "is language the key to human intelligence?" (which forms the title of his piece), it may be more productive to ask "is intelligence the key to human language?"


Blogger Roti said...

I believe, that the question of "is intelligence the key to human language?" may be answered by looking at some specialisations in our daily lives.

Specialisations would mean like, professions, philosphical thought, dialects, and other place/situation specific activities.

I believe, this can be seen clearly by looking at the language that we use, especially in higher learning and very advance fields of research. For example: in research, we make new terms because we have found some new anomaly, and even in computer games we make new strategies or moves that compute to higher levels of competency. These levels of competency or new anomalies come from the same process of cognition. Human intelligence, as has been found or theorised to have many forms, brings a person to be extremely adept at fulfilling a certain task, which is often said to be his or her skill.

Human language, i believe have evolved to become liable to methaphoric interpretation because our language is based on the abilities of cognition. Cognition is a process of thought, and humans are the most adept in thought that any other mamal in this world. We rely not on sign language anymore, but on the functions of our cognition. Metaphors, are a form of linking our thoughts to the many possibilities and then bringing them into context. I believe, that the levels of cognition that one has, determines their ability to understand metaphors. In this context, i say that cognition is used to find out the many possibilities of action based on that metaphor. Then, we use a trial-and-error method to try and relate that action to the current situation/context. I use action, because methaphors or words are firstly based on action, then transcribed into words because that word provides a similar description of that action.

I believe, in Premack's statement that the "evolved" meant that it was evolved from biological factors. Example would be like limbs of humans or human control of our limbs. As we evolved, we lost control of some body functions and also gained extra control over other body functions (e.g. probably extensive facial expression). Compared to our ancestors that it has says we evolved from, we have differences in our bodily agility and dexterity. That is what probably explains our ability and also disability to carry out daily tasks.

I think that the "invented" part would mean that from our cognition processes, we have invented many new words or terms for our similar but specialised actions. Example: collusion and conniving. These two words are similar in nature because they both talk about conspiracy. Though, they are used in two different context. A collusion would be a band of market powers in economics trying to make an illegal pact or conspiracy. Conniving would be talking about conniving criminals that conspire to commit and act of harmful nature towards another party. As you may see, both terms talk about conspiracies to doing actions of harmful nature. But why didn't we just stick to one word, and had to make another new word for each context? Why can't we say collusion of criminals? I believe, it is because our cognition makes us see it in two different contexts. Thus, our level or maybe type of intelligence, fully based on cognition, determines that we put it in words that give us a specific nature of the action. Again, the term specialisations is seen in "specific".

I believe, that the chimps may be using not just their mental cognition process to "see" information but also their senses. We know that fish can pick up electro-magnetic pulses, perhaps other mamals may be able to use their senses to pick up emotions? Perhaps, their "spoken language" may only be based on their physical actions but their emotions may also play a part in determining they type of message that is sent out to the other individual in their society.

In conclusion, i am hypothesising that we as humans who have developed an intelligence based almost fully on cognition, tend to use very specific terms for our actions because we do not rely on other sense to interpret the true meaning of words; but other animals may use not only their cognition, but also their other senses in the interpretion process.

8/31/2006 07:35:00 AM  

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