Common Ground

Boston common serves as the metahphor for the shared psychological abstraction where speakers focus their joint attention.

The current (May/June) issue of Child Development has a series of articles on the role of pointing and evolution/development of language. The lead article in the series is “A New Look at Infant Pointing” (abstract here) by Michael Tomasello, Malinda Carpenter, and Ulf Liszkowski. It is largely a repeat of ideas discussed on this blog recently under the title Infant Collaborators. The basic thesis discuss there is that speech is a method for collaborating on a common psychological ground, and that a useful tool in this collaboration is pointing. Humans, according to this view, are unique for sharing purposes and meanings. Thus, the central proposition of the Child Development series is already familiar to regular readers of this blog. The most important contribution of the Child Development series is the range of expert criticisms and extensions of this idea that are offered.

An article by Barbara D’Entremont and Elizabeth Seamens “Do Infants Need Social Cognition to Act Socially?” (abstract here) disagrees with the main thesis on philosophical grounds. They argue that one-year-olds are too young to have concepts of self and others as intentional agents, and therefore cannot have communicative intentions.  They advocate a “lean” interpretation that says infants point simply to gain attention. In other words, pointing does not introduce a topic into the relationship and, therefore, is outside the “attentional triangle” (speaker, listener, and topic). The infant points at, say, a toy, not because it is interesting in the toy but to draw attention to itself. Look at me, I see a toy.  It is often true that some forms of speech—witticisms, repartees, and sharp rebuttals—are only secondarily about the topic. The main point is to persuade everyone of the cleverness of the speaker.

That explanation does not work in this case, however, and it is notable that the argument in its favor is a priori—such speech cannot be!—rather than empirical. Tomasello’s team has demonstrated time and again that if an infant points to, say, a music box and the adult looks at a teddy bear, the infant tries to correct the adult’s mistake, redirecting them to the music box. Besides, pointing cause a person to look away from the pointer, while a witticism commonly evokes an appreciative stare at the wit. It is no surprise that other commentators do not accept the lean interpretation, even if they are doubtful of the Tomasello team’s “rich” interpretation with its complex motives and understanding.

The next article, “Pointing Behaviors in Apes and Human Infants,” (abstract here) by Juan-Carlos Gómez continues this inquiry, proposing a middle ground between lean and rich interpretations. It provides more evidence of the disquiet aroused by the growing evidence of very early, uniquely human behaviors in infants.  The central point for this blog, however, is its comparison of ape and human-infant pointing. It finds exactly what we have discussed on the blog before. Ape pointing is abundant, but apes do not point to share as part of shared intentions. They do not even rise to the level of the lean interpretation. They point to get others to act as their agents. Their pointing typically indicates Gimme dat and does not even rise to the level of showing off.

More valuable are the last two articles which examine the question of just what function does infant pointing serve? One article (abstract here), by Victoria Southgate, Catharine van Maanen, and Gergely Csibra asks if infants really point as part of shared intentionality or if it is to learn.

In some ways the effort to understand an infant’s communicative behavior seems as mysterious as trying to discover the evolution of communication. You may have evidence, but what underlies it? Southgate et al. argue that Tomasello’s team is “too quick to assign prosocial cooperative motivations to preverbal infants” and that they infants might be motivated by a request for information. The more altruistic drawing a person’s attention to something interesting goes by the wayside with this view.

I don’t have the space to go through their whole analysis here, but as a minimum they establish that the case is ambiguous. An infant may point to learn something, like the name, of an object, or it may be pointing something out. So we cannot insert the “rich” interpretation without richer evidence. Where then does that leave us? It seems to me that it makes the data for joint attention and a common ground even more robust. Southgate et al conclude:

We applaud the careful demonstrations that infant pointing is a true communicative act, and not just a conditioned response, from the outset. However, claiming that this act is driven by deeply social cooperative motives seems to go to far. (p. 739)

They also say:

While declarative communication [pointing to inform] does not necessarily imply a dialogue, interrogative communication [pointing in order to be informed] does, which explains why the situation commonly characterized as “joint attention” is required for infant pointing. (p. 739)

So, as a minimum the data seem strong for asserting that infants naturally communicate about things outside themselves (topics), and depend on joint attention to a common ground to make such communication possible.

The final paper in the series, “Pointing Sets the Stage for Learning Language—and Creating Language,” by Susan Goldin-Meadow (abstract here) is presented a an extension of the Tomasello team’s study, but works just as well with Southgate’s attention to communicating to learn.  “The early gestures that children produce not only predate their words, they predict them. “ (p. 741) It presents extensive evidence that children learn new words by pointing at things and finding out what things are called. For example, a child might say, “Look,” and point at a teddy bear. Mom replies, “A bear. Yes, it’s a bear.” Not surprisingly, the child is soon calling the teddy bear, bear.

These studies take another point for granted, the willingness of parents to teach their children. It is that willingness that has enabled human-raised chimpanzees to go so much further in learning sign language than do wild chimpanzees. The pointing gestures therefore seem to establish very clearly that the rise of a common language requires joint attention, common ground, and the willingness of at least some communicators to teach others how the system works. (I’ll have more to say about Goldin-Meadow next week.)