The development of human language plays a complex role within this process of adaptation. It seems to have developed from signalling among social animals; but I propose the thesis that what is most characteristic of the human language is the possibility of storytelling.
It may be that this ability too has some predecessor in the animal world. But I suggest that the moment when language became human was very closely related to the moment when a man invented a story, a myth in order to excuse a mistake he had made – perhaps in giving a danger signal when there was no occasion for it; and I suggest that the evolution of specifically human language, with its characteristic means of expressing negation – of saying that something signalled is not true – stems very largely from the discovery of systematic means to negate a false report, for example a false alarm, and from the closely related discovery of false stories – lies – used either as excuses or playfully.
If we look from this point of view at the relation of language to subjective experience, we can hardly deny that every genuine report contains an element of decision, at least of the decision to speak the truth. Experiences with lie detectors give a strong indication that, biologically, speaking what is subjectively believed to be the truth differs deeply from lying. I take this as an indication that lying is a comparatively late and fairly specifically human invention; indeed that it has made the human language what it is: an instrument which can be used for misreporting almost as well as for reporting.