Infant Collaborators

Speaking of collaboration, I found this cartoon over here at the Goodwill site.

The central dispute in today’s study of speech origins concerns the nature of speech itself. The classic position has been that it is a system for expressing and organizing symbolic meanings. Much of twentieth-century philosophy was devoted to figuring out what symbols were and how they worked. Last week’s post on the variety of gestures that chimpanzees and bonobos make reported on a new report arguing “that gesture has become a serious candidate for the origins of expressing ‘symbolic meaning in early hominins.’”

This week’s post looks at the rival understanding of speech, one that says it is a system for directing and sharing attention. An article about “Shared Intentionality” (abstract here) published earlier this year by Michael Tomasello and Malinda Carpenter in the journal Developmental Science contrasts infant/toddler behavior with that of chimpanzees. Unlike the study of gestures, this article finds that there is a very serious difference between human and ape behavior.

For a science paper, the Tomasello and Carpenter article has a chatty tone. It begins:

Human cognition seems very different. Unlike other animal species, human beings use language, make mathematical calculations, create social institutions, build skyscrapers, use maps, marry one another, form governments, use money, and on and on.

For some years now we have been trying to figure out what enables humans, but not our nearest primate relatives, to do these things. After a few false starts we have zeroed in on a suite of social-cognitive and social-motivational skills that may be collectively termed shared intentionality … [a term that] refers to collaborative interactions in which participants share psychological states with one another. … The big Vygotskian idea is that what makes human cognition different is not more individual brainpower, but … the ability of humans to learn through other persons and their artifacts and to collaborate with others in collective activities. [p. 121]

Speech is the most important example of this shared intentionality. It is learned by interacting with other people, it enables one another to share psychological states, and it enables collaboration in joint activities. It is the sine qua non of all other shared activities, with the possible exception of certain ecstatic communions that use music. But in those cases the ecstasy is the point and does not, of itself, lead to collaboration. For that you need speech. Then you can get the math, the social institutions, the skyscrapers, etc.

It might seem that since shared intentionality has led to such great success among humans, that its absence elsewhere is a great mystery. Why don’t chimpanzees work together to reach go high in trees and collect hard-to-reach food? Evolutionary theory, however, reverses the mystery for it turns out to be easy to explain why chimpanzees don’t collaborate?

Freeloaders are the universal problem of collaboration. They reap the benefits of other’s labor while providing nothing themselves. Viewed in strict Darwinian terms, it is everyone’s interest to be a freeloader. Costs are low, rewards are high. Meanwhile for the provider, costs and rewards are more in balance. Thus, any mutation that produces a freeloader should prosper in a collaborative society. But as freeloaders grow, the providers’ costs go up and rewards go down. The situation is unstable. The parasites overwhelm the providers and the society collapses. Collaboration is not self-sustaining; except that, obviously, in the case of humans, it is. The mystery is how did humans escape the trap to become a prospering, self-sustaining, collaborative species.

The Tomasello-Carpenter paper examines four ways human infants develop collaborative behavior while chimpanzees do not:

• Joint attention: Chimpanzees pay attention to where other chimpanzees are looking. Human infants do the same, but, starting at age one, humans also attempt to share attention with others. Joint attention is more than two individuals paying attention to the same thing at the same time. It is two people experiencing the same thing at the same time and knowing that they are doing so. Collaboration depends on this shared, subjective ground (what Tomasello and Carpenter call ‘common ground’).
• Cooperative communication: Chimpanzees are masters of communication for purposes of social manipulation. Apes who are raised by humans soon discover the human willingness to be of service and they develop a variety of gestures that can instruct humans to do their bidding (e.g., give them food or tools, transport them somewhere, etc.). That behavior is classic communication as control. But human infants go further.  As early as 14 months infants are able to communicate and understand gestures that are relevant to a shared, common ground. I remember very well playing roll-ball with a nephew barely a year old. The ball rolled under a desk. My nephew did not know where the ball was. I pointed, he looked and then got my meaning. He looked under the desk and found the ball. The common ground provided by the game enabled an infant to understand me. Chimpanzees, however, do not recognize that psychological commonality and do not refer to a common ground in their own gestures. They also appear unable to understand gestures that depend on their recognizing the common ground. Chimpanzee communication is controlling and individualistic, while human, year-old children are already capable of using and recognizing gestures that are relevant to a shared interest. (Note: Last March this blog examined a book by Jean Louis Dessalles titled Why We Talk, summarized here. In that book Dessalles makes a big point about conversations having to be “relevant,” and our ancestors being selected to make relevant remarks. But this  research by Tomasello and Carpenter underscores the way that focus on relevance skips a point. First there has to be a subjective, common ground. The break with individualism precedes relevance, which is why I concluded in the end that Dessalles’ book was Insufficiently Radical.)
• Collaboration: Chimpanzees engage in complex group activities. They can even hunt in groups. Many other animals—e.g., hyenas, lions, wolves, and ants—engage in group hunting as well and there is much disputation over whether these are true collaborative efforts in the furtherance of a joint goal, or whether each individual is pursing its own goal while taking the actions of others into account. It might seem like a hopeless dispute, but there are many elements found even in very young, human collaborations that are never found in animal groups. For one thing, when individual animals drop out from a group activity, others do not try to persuade the quitter to rejoin, whereas even 14 month old infants try to reconnect with the other. Another peculiarly human activity is engaging in collaboration for collaboration’s sake. Social games are of this sort are commonplace among human children, and, typically, when players reach the goal, they start over again. The point of such play is the joint activity, not really the goal. Nothing like that is seen in the animal world.
• Social Learning: Chimpanzees learn from others through the useful technique of watching what others do. Human infants learn that way too, but people also learn by being shown and told what to do. Humans are also much better mimics than apes. The old saying, "Monkey see, monkey do," is quite wrong. Monkeys only do something they saw done, if they also recognized the utility of the action. If you includer a prayer gesture before reaching into a hole and pulling out food, monkeys will follow suit and reach into the hole, but they won't include the prayer. Human children, seeing such an action, do include the extraneous gesture. They don't know why, but they follow social norms much more closely and are thus able to learn a skill whose value is not immediately obvious.

These areas all build on what can already be found among primates, but then give them a special twist. Primates are individuals and if they did have language, their pronouns would by I, me, and my. —I want a tickle; my tooth hurts; give me a banana. Indeed, those phrases pretty well sum up what chimpanzees and gorillas can manage to say when taught sign language. Humans of course say all those things, but they also have another set of pronouns that seem quite unnecessary for other primates: join us in our game; we want a hit, we want a hit; they’re playing our song.

That seems to be the essential requirement of speech. It is not symbolic thinking, which is older than humans, but a shared psychological ground.

Comments

[Vijayachandra Ramachandra]

I was thinking of theory of mind and how it fits within this framework (having a common ground). I think joint attention (two people looking at an object and also sharing that experience) would be a first order theory of mind. Don't chimps and other primates have this? Is it fair to say that they do have a TOM but they use it only for selfish purposes ?
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BLOGGER: What goes on in the mind of a monkey or an ape is always going to be something of a mystery, so we are forced to look at their behavior. That approach uncovers a striking difference between humans and other primates.