Stiffness and plasticity in social learning strategies. An idea of interpretation.

In Anthropology, Di Paolo, Philosophy of Cognitive Sciences on March 19, 2013 at 6:11 PM

Several useful behaviours that an individual must apprehend for growing up require the presence of “friendly” co-specifics in a social context. In primates, various strategies of Social Learning are present, mostly relying on an individual’s ability to solve problems by trial-and-error, but some of apes are able to show imitative learning, considered pivotal for cumulative culture. Chimpanzees have been recognized, even if not by all the scholars, able to switch between an individual, plastic but less accurate method of learning (both a trial-and-error strategy properly and emulative learning), and true imitation, depending on the quantity of relevant information at disposal in a causality task (Whiten et al, 2005; 2009). Rather, human children are incredibly stiff in copying adults, doing it not only when it is useful, but also when it is wasteful, disadvantageous and harmful. Later in their development they become able to choose more plastic and individual strategies. Some authors (Tomasello in primis, e.g. Tomasello, 2005; 2009) have pointed to this fully developed imitative behaviour as the main cause of human uniqueness, but this idea seems quite strange considering the vast amount of data we have at disposal on non-human culture and the use of imitation by some enculturated apes (e.g. McGrew, 2004; Byrne, 2007; Whiten, 2011; Tomasello & Call,2004; Call, 2011); . How is it possible, indeed, that these latter (even if, as usually recognized, not all captive apes) are able to imitate, if imitation appeared suddenly in humans, as a human adaptation, founding our “overbearing” life-style? Data on human-raised/enculturated chimpanzees demonstrate that imitation is something that can be exhibited by other species as well, meaning that it is something already present in the repertoire of these other species (Call & Tomasello, 1996; Bering, 2004; Tomasello & Call, 2004; Call, 2011). Consequently we are allowed to think that somehow imitation developed at least before the separation between hominid lineages and chimpanzee/bonobo ancestors. Imitative behaviour is usually displayed by enculturated/human raised apes  and that because in the cultural context it seems more useful, or only more probable. However then, another interesting question comes up and it concerns the use of imitation by human children, that they do pedantically at least till they start to speak fluently. Probably, an economical explanation could be that humans only re-use same learning strategies inherited from their ancestors, shared with their evolutionary relatives, but they do it differently. Together with social explanations, the preponderance of imitative learning in humans is probably due to the open environment in which hominins evolved: in this environment, in fact, reaching food was more difficult than in forests. Because of this difficulty, probably copying faithfully successful actions was better than trying to reach the same goal with an individual strategy. And they did so again and again. Therefore, the rigid use of imitation by human children may be derived exactly from that: humans become very good to firstly learn necessary information by means of imitation, and only later and over this ground, each individual can add something personal, using a trial-and-error process. Cumulative culture, so, could not depend on a specific learning strategy, but more on differences in using already existing strategies, spreading them over different developmental steps.

Laura Desirée Di Paolo

Call, J. (2011) How Artificial Communication Affects the Communication and Cognition of the Great Apes. Mind and Language, 26, 1: 1-20.

Call, J. & Tomasello, M. (1996) The effect of humans on the cognitive development of apes. In A.E. Russon, K.A. Bard & S.T. Parker (Eds). Reaching into thought (pp. 371-403); Cambridge: Cambridge University Press.

Bering, J. (2004) A critical review of the “enculturation hypothesis”: the effects of human rearing on great ape social cognition; Animal Cognition, 7, 4: 201-212.

Byrne, R W. (2007) Culture in great apes: Using intricate complexity in feeding skills to trace the evolutionary origin of human technical prowess. Phil. Trans. R. Soc. B,. 362: 577-585

McGrew,W.C. (2004) The Cultured Chimpanzee: Reflections on Cultural Primatology. Cambridge University Press, 248 pp.

Tomasello, M. & Call, J. (1997) Primate Cognition. New York-Oxford: Oxford University Press.

                                           (2004) The role of humans in the cognitive development of apes revisited. Animal Cognition, 7:213-215.

Tomasello, M., Savage-Rumbaugh, S., Kruger, A.C. (1993) Imitative learning of actions on objects by children, chimpanzees, and encultured chimpanzees. Child Development, 64: 1688-1705.

Whiten, A. (2005). Chimpanzee cultures. In J. Caldecott. & L. Miles (Eds) The World Atlas of Great Apes and their Conservation (United Nations Environment Programme). Berkeley & Los Angeles: University of California Press.

                         (2005). The second inheritance system of chimpanzees and humans. Nature, 437, 52-55.


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