There is not really much difference between the position I expressed on this and what Nancy has now expressed. What differences exist may be only matters of emphasis. I certainly do not reject biology (obviously, there is nothing in human behavior which is inconsistent with biology). Sixty years ago Susanne Langer suggested that ritual came first and that language was derivative from 'oral' accompaniment to ritual. That position is not too different from Tattersall's speculation, since children's group play tends to be highly ritualistic. Language as we know it has implicit in it not only thinking about the world but thinking about thinking -- and it is hard to imagine that emerging suddenly with the birth of the first homo-sapiens: hence the assumption that the history of language is not coterminous with the history of biologically modern humans. Carrol P.S. One of the puzzles of animal psychology relevant to this topic is that a number of animals engage in deceitful behavior: and deliberate deceit implies some analogue at least to consciousness of the other's thought processes.