Saturday, October 26, 2013

Michael Tomasello, The Origins of Human Communication (2008)

Every work morning I board the subway to travel to my office, and approximately halfway on this journey I change trains.  Changing trains entails exiting a train into a crowd of people who are looking to board the train I am leaving, walking some 50-70 steps to a staircase while passing many people who are, like myself, leaving the train I just left, or, heading in the opposite direction to the train I just left.  I descend stairs to another platform and then walk roughly 20 steps on the platform to wait for an oncoming train that will take me to my destination.  During this change of trains, I probably come close to 100 or more persons within a 5-10 foot radius of my person. I do not know these people.  Most people are not talking.  A few I recognize as having seen previously on this journey, but still I don't know them.  I don't talk with them.  Some I see only out of my peripheral vision.  The amazing part of this brief, everyday journey navigating through a mass of people is that I almost always avoid any physical contact with them, and the same is true for most of them as well.  It is easy to think that each individual is merely moving autonomously toward their individual goal, but the reality is that each individual is acting cooperatively with the others to ensure that the others are able to move toward their individual goals by not colliding (with modest, likely accidental exception) or inhibiting the others as they move.  It is like a dance.  Occasionally someone crosses diagonally in front of me, but I avoid a collision by slowing down or moving sideways.  Avoiding contact with and staying out of the way of other moving persons is a shared intention; in the case of humans, cultural rules have played a key role in enabling the individual to realize their shared intention:  e.g., stay on the right of oncoming persons; follow the person ahead of you.  But the individuals are not merely blindly following rules; they are watching the faces and body movements of others and reading their minds. 

Place a camera high above this subway station and make a video of the masses transitioning between trains.  The flow of people almost seems choreographed; it is not as chaotic as one might think it could be.  Now watch this video of ants marching.  The movement of ants seems just as orderly as my video of humans passing in the subway station.  But it is different.   Ants communicate differently, relying on chemicals and touch. They are acting automatically, inflexibly.  Chemotaxis (see May 19, 2013 post) is at play here.  In contrast, humans read the intentions of other humans in their facial expressions, gaze, and motions (see July 16, 2010 and  September 18, 2009 post), even when no words or spoken, and this is relatively unique in the animal kingdom.  Apes are known to understand intentions of others, and apes are known to experience empathy.  (See November 9, 2010 post). Mirror neurons, which some argue enable us to feel what others are feeling or experiencing, were first discovered in monkeys.  (See September 18, 2009 post).  What apes do not do --- and humans do, according to Michael Tomasello --- is share intentions and goals with others.

Mindreading introduces us to theory of mind.  (See November 21, 2012 and  June 12, 2011 posts) It is not a "theory" so much as it is a state of awareness:  our ability to attribute mental states to others --- mindreading.  In my little "everyday vignette" just described, our theory of mind is almost unconscious, and I would submit that this ability is close to unique, if not unique in the animal kingdom. If apes enjoy a theory of mind, it is certainly not as well-developed as humans.  It plays out in nearly every other human scenario imaginable because we are social animals.  (See November 21, 2012 post).  Our theory of mind undoubtedly varies among these scenarios, for example, if our attentiveness to something specific about another person is heightened, there is probably a heightened attentiveness to another's specific mental state; whereas in my vignette the subway passenger's theory of mind is likely ascribing generic mental states to the masses of other humans around. 

Michael Tomasello's Origins of Human Communication is not specifically about verbal speech or language, which is the focus of Christine Kenneally's The First Word.  (See August 31, 2009 post).  It is about human communication. In Tomasello's view, language is not hardwired genetically into the brains of humans, and while he does not debate whether language is an adaptation or exaptation (see October 25, 2011 post), Tomasello treats language as an emergent property, emerging from antecedent forms of human communication --- specifically gestures such as pointing or pantomiming.  And Tomasello is armed with a lot of research data to advance his argument.  Given that humans do not generally utter a spoken word of language until they are older than one year (14-18 months), Tomasello finds his antecedents in babies and, with an evolutionary longer gaze, in apes, the genetically closest animal to homo sapiens sapiens.  Pointing and pantomiming are gestures human babies use before they begin to speak (with language essentially becoming a substitute for pantomiming). 

Tomasello's thesis is that the "ultimate explanation for how it is that human beings are able to communicate with one another in such complex ways with such simple gestures is that they have unique ways of engaging with one another socially.  More specifically, human beings cooperate with one another in species-unique ways involving processes of shared intentionality."  By "simple gestures," Tomasello is referring to the acts of pointing and pantomiming.  He notes that apes point and respond to pointing, but the key difference here with humans is that when apes point they are making requests --- demanding action by others. "Bring me that food." Apes possess the ability to follow gaze direction.  Apes want the other to see something and do something.    Humans, by contrast, point not only to direct the other human's attention to something, but to share information with others, request help and cooperation, even when there is no benefit to themselves.  (See September 27, 2012, September 12, 2012, and October 13, 2010 posts for discussions of direct and indirect reciprocal altruism). "Pointing," says Tomasello, "is based on humans' natural tendency to follow the gaze direction of others to external targets, and pantomiming is based on humans' natural tendency to interpret the actions of others intentionally.  This naturalness makes them good candidates as an intermediate step between ape communication and arbitrary linguistic conventions [of humans]."  While there are some primatologists who credit apes with more cooperative, social behavior than Tomasello acknowledges, what differentiates apes and humans, he says, is an underlying psychological infrastructure --- made possible by cultural learning and imitation that allows humans to learn from others and understand their intentions.  That leads to shared intentionality --- sometimes referred to as "we" intentionality --- collaborative interactions in which participants share psychological states with one another and have shared goals and shared action plans.  This brings us to the research observations about human babies.  Tomasello (2007):

"[H]uman adults quite often teach youngsters things by demonstrating what they should do – which the youngsters then respond to by imitating (and internalizing what is learned.  Adult chimpanzees do not demonstrate things for youngsters (or at least do this very seldom). Interestingly, when human adults instruct their children in this way (providing communicative cues that they are trying to demonstrate something), 14-month-old infants copy the particular actions the adults used, and they do so much more often than when adults do not explicitly instruct – in which case they just copy the result the adult achieved (Gergely & Csibra, 2006). Furthermore, there is some evidence that 1-year-old infants are beginning to see the collaborative structure of some imitative interactions. Thus, they sometimes observe adult actions directed to them, and then reverse roles and redirect the actions back to the demonstrator, making it clear by looking to the demonstrator’s face that they see this as a joint activity (Carpenter, Tomasello & Striano, 2005). Chimpanzees may on occasion redirect such learned actions back to their partners, but they do not look to their partner’s face in this way (Tomasello & Carpenter, 2005). Thus, chimpanzees’ social learning is actually fairly individualistic, whereas 1-year-old children often respond to instruction and imitate collaboratively, often with the motivation to communicate shared states with others.


 "Human children, on the other hand, often are concerned with sharing psychological states with others by providing them with helpful information, forming shared intentions and attention with them, and learning from demonstrations produced for their benefit. The emergence of these skills and motives for shared intentionality during human evolution did not create totally new cognitive  skills. Rather, what it did was to take existing skills of, for example, gaze following, manipulative communication, group action, and social learning, and transform them into their collectively based counterparts of joint attention, cooperative communication, collaborative action, and instructed learning – cornerstones of cultural living. Shared intentionality is a small psychological difference that made a huge difference in human evolution in the way that humans conduct their lives.

"In terms of ontogeny, Tomasello et al (2005) hypothesized that the basic skills and motivations for shared intentionality typically emerge at around the first birthday from the interaction of two developmental trajectories, each representing an evolutionary adaptation from some different point in time. The first trajectory is a general primate (or perhaps great ape) line of development for understanding intentional action and perception, which evolved in the context of primates’ crucially important competitive interactions with one another over food, mates, and other resources (Machiavellian intelligence; Byrne; Whiten, 1988). The second trajectory is a uniquely human line of development for sharing psychological states with others, which seems to be present in nascent form from very early in human ontogeny as infants share emotional states with others in turn-taking sequences (Trevarthen, 1979). The interaction of these two lines of development creates, at around 1 year of age, skills and motivations for sharing psychological states with others in fairly local social interactions, and then later skills and motivations for reacting to and even internalizing various kinds of social norms, collective beliefs, and cultural institutions."

The cooperative homo hunter-gatherer phenomenon is believed to have emerged among homo erectus, hundreds of thousands of years before homo sapiens. (See November 21, 2012 post).  Exactly when their social structures emerged is a matter of debate, but as forms of homo cooperation evolved forms of communication would be expected to emerge as well and how those forms of communication might have evolved is what Michael Tomasello explores in The Origins of Human Communication.   The timing of the emergence of verbal language among homo is also a matter of debate and no consensus, but some put that event as occurring among homo sapiens 50-70,000 years ago and perhaps as early as 100,000 years ago, but perhaps earlier.  That timing would correlate with what we believe is the evolutionary origins of modern humans, homo sapiens sapiens, in Africa. Whatever the timing for the origins of human speech, there is a gap of hundreds of thousands of years between the origins of communication and verbal speech. But it is over these hundreds of thousands of years, if not over a million years, of the evolution of cooperation among the species of genus homo, that the psychological infrastructure critical to human eusociality cited by Tomasello developed:
"[O]ur proposal," Tomasello writes, " is the relatively uncontroversial one that human collaboration was initially mutualistic --- with this mutualism depending on the first step of more tolerant and food-generous participants [see e.g. March 28, 2013 post].  The more novel part of the proposal is that mutualistic collaboration is the natural home of cooperative communication.  Specifically, skills of recursive mindreading arose initially in forming joint goals, and then this led to joint attention on things relevant to the joint goal (top-down) and eventually to other forms of common conceptual ground.  Helping motives, already present to some degree in great apes outside of communication, can flourish in mutualistic collaboration in which helping you helps me.  And so communication requests for help --- either for actions or for information --- and compliance with these (and perhaps even something in the direction of offering help by informing) were very likely born in mutualistic collaboration.  At this point in our quasi-evolutionary tale, then, we have, at a minimum, point to request help and a tendency to grant such requests --- with perhaps some offers of help with useful information --- in the immediate common ground of mutualistic collaborative interactions."

Helping by informing becomes the cornerstone of indirect reciprocity, which Martin Nowak finds makes humans "supercooperators:" the only species that "can summon the full power of indirect reciprocity, thanks to our rich and flexible language."  (See September 17, 2012 post).

Missing from Tomasello's discussion of social cognition and the human communication is the emotional content and perhaps underpinnings of that communication.  Tomasello cites inflexible ape vocalization as "tightly tied to emotion," but as prior posts in this blog point out there is uniquely human social behavior anchored in emotions arising in the more ancient part of our brains.  (See May 19, 2013 and November 21, 2012 posts).   Jaak Panksepp's discussion (May 19, 2013 post) of the care system, the grief system, and the play system are just examples of the emotional underpinnings of the psychological infrastructure that Tomasello relies upon to build his viewpoint.  I do not purport to have read everything that Tomasello has researched and written, so maybe this discussion occurs elsewhere.  I note that he does comment in his 2005 article, that "theorists such as Trevarthen (1979), Braten (2000), and especially Hobson (2002), have elaborated the interpersonal and emotional discussions of early human ontogeny in much more detail than we have here.  We mostly agree with their accounts . . ."

There are two final points in this discussion.  First, the evidence from babies supports the conclusion that our social cognition and behavior is not innate.  Tomasello calls this ontogenetic, which is the nurture side of the nature versus nurture (post natal learning) debate.  (See September 18, 2009 post).  With respecting to language, for example, V.S. Ramachandran believes that what is innate is our "capacity for acquiring rules of language," not language or verbal speech itself.  (See October 25, 2011 and February 15, 2012 posts).  Tomasello certainly concurs with the view that "[t]he actual acquisition of language occurs as a result of social interaction. Ramachandran believes that language was enabled by cross linkages in the brain between different motor maps (e.g. the area responsible for manual gestures and the area responsible for orafacial movements).  (Id.)  Second, Marco Iacoboni's suggestion (September 18, 2009 post) that the individualistic or competitive models of human behavior leave much to be desired is worth invoking.  As a prior post (id) observed, "Self and other are 'inextricably blended,' says Iacoboni. The sense of self follows the sense of 'us,' which is the first "sense" of awareness an infant has immediately following its birth as a result of mother infant interactions. We are social animals first."  While competition and individual behavior is not necessarily a vice and might be deemed virtue (see January 30, 2010 post), it is not the endpoint in our understanding and modeling of our human cognitive framework.   In the contentious political conversation that now embraces America, it is not sufficiently recognized that the social and cooperative dimension of the human cognitive framework is dominant to competition in that framework as well as our evolutionary history as a key to human survival.  (See November 21, 2012 and August 22, 2012 posts).  If we can cooperatively navigate our way successfully through a subway station without thinking too deeply about what we are doing, we ought to be able to collaboratively solve a public policy issue.

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