Phylogenetic time and symbol creation: Where do zopeds come from?

The data provided by the archaeological record currently lead to the conclu sion that modem human anatomy was in place well before the modem species sh owed its species-typical, symbolically mediated behaviours. This temporal d isjunction-between modem human biology and the modem behaviours it supports -poses the question as to how the elaboration of our symbolic behaviours ma y have occurred. The only field in which there is data as to how symbolical ly mediated activities are elaborated is ontogeny, both of humans and of la nguage-immersed apes (and possibly some parrots and cetaceans). Here curren t accounts tend increasingly to draw on Vygotsky's concept of the 'zone of proximal development' (zoped), portraying the socially constructive nature of the process of mastering symbols. However, ontogeny is notoriously diffi cult to reconcile with phylogeny at the best of times, and it becomes much more so in this traditional Vygotskian context, for a zoped account require s that one member of the interaction 'has' the resources that are being soc ially transacted to the 'novice'. This possession begs the phylogenetic iss ue. This paper lays out an account of how a zoped may be created sui generi s through the joint actions of equals, so as to provide an essential compon ent in the bootstrapping of symbol systems. Symbols are described as having implicit properties, and it is the 'discovery' of these implications that is the engine of cultural change. These 'discoveries' require both a biolog y that can accomplish them and certain conditions of joint action to enable them.