Published online by Cambridge University Press: 25 October 2005
We propose that the crucial difference between human cognition and that of other species is the ability to participate with others in collaborative activities with shared goals and intentions: shared intentionality. Participation in such activities requires not only especially powerful forms of intention reading and cultural learning, but also a unique motivation to share psychological states with others and unique forms of cognitive representation for doing so. The result of participating in these activities is species-unique forms of cultural cognition and evolution, enabling everything from the creation and use of linguistic symbols to the construction of social norms and individual beliefs to the establishment of social institutions. In support of this proposal we argue and present evidence that great apes (and some children with autism) understand the basics of intentional action, but they still do not participate in activities involving joint intentions and attention (shared intentionality). Human children's skills of shared intentionality develop gradually during the first 14 months of life as two ontogenetic pathways intertwine: (1) the general ape line of understanding others as animate, goal-directed, and intentional agents; and (2) a species-unique motivation to share emotions, experience, and activities with other persons. The developmental outcome is children's ability to construct dialogic cognitive representations, which enable them to participate in earnest in the collectivity that is human cognition.
1. Note that in a situation in which current reality matches the desired goal state, the organism will not behave (it will have no desire to behave because its goal is already met). It is also possible that, in some cases, inaction is a good strategy for bringing the world in line with one's goals. That is, in some cases, inaction may be intentional action, an insight possible only if one considers all of the components of a control system working together.
2. This study – or any other with its same logic – has yet to be done with younger children. It might be argued that the study by Gergely et al. (1995) showed that infants know that organisms adjust their behavior to reality constraints in the form of obstacles. But the dishabituation methodology does not enable such an inference because the child does not have to choose an action plan herself (as in imitation studies). Thus, in that study, infants only needed to discriminate normal from abnormal behavior: goal-directed agents do not normally take circuitous routes to goals. (A similar argument applies to the study by Woodward & Sommerville 2000.)
3. In some accounts of shared intentionality, it is enough that we both have the same goal and know that we do (i.e., have mutual knowledge of the fact that we both have the same goal). But this is not enough; we might each want the box open and know that the other does also, but still not form a shared goal (perhaps we will compete to see who can open it). Further, it is also not enough simply to have goals about our behaving together. If I suggest we go to the movie together, my desire is not that you come because your mother forced you to but because you want to – I want us to have a shared commitment. (Note, however, that because of the hierarchical structure of action, there may exist many mixed cases in which you collaborate reluctantly because of competing goals and so forth.)
4. In a different experimental paradigm, Myowa-Yamakoshi and Matsuzawa (2000) and Call et al. (2005) both used Meltzoff's (1995) behavioral reenactment procedure (involving trying and failed attempts) with chimpanzees. Both found that chimpanzees, like children, performed the target action equally as often when they saw a failed attempt as when they saw the completed action. However, in both studies, chimpanzees also performed the target action at high levels in a baseline condition containing no demonstration at all, which seriously limits what can be concluded about the subjects’ understanding of the modeled action.
5. Vervet monkey alarm calls and the like do not need to be interpreted as referential, and indeed individuals have very little control over their production at all (Owren & Rendell 2001). Moreover, there is no evidence that any ape species uses such calls (Tomasello & Call 1997).
6. Although sometimes presented in this way, the study by Povinelli et al. (1992) has other interpretations not involving role reversal (Tomasello & Call, 1997).
7. Evidence for this view is provided by experimental studies in paradigms such as (1) the ultimatum game in which individuals offer more money to others than would be beneficial from a selfish viewpoint, at least partly because this seems like the “fair” thing to do (Gintis et al. 2003); and (2) experimental games in which individuals go to great lengths to punish others who are not being “fair” even when this punishing act could not possibly lead to future benefits for the punisher that outweigh the costs (on altruistic punishing, see Fehr & Gächter 2002).
8. That is, at least with respect to basics – specific environmental differences may of course create important individual differences, some considered atypical or even pathological.
9. Barresi and Moore (1996) are focused on a different problem, claiming that in order to attribute psychological states to others at all the infant must first interact with them in situations in which they both have similar psychological reactions. We are focused on collaboration and dialogic cognitive representations among agents who already understand one another intentionally, and our hypothesis is that the child internalizes these interactions into cognitive representations that encompass simultaneously both first-person and third-person perspectives.