...This can be illustrated by a melody or a spoken sentence: we hear the current tone (presentation), but are at the same time still aware of the tones just heard (retention), and vaguely expect the continuation of the melody (protention). Consequently, what is perceived is not a sequence of single moments but a dynamic, self-organizing process, which integrates the tones heard into a melody, or words into a sentence.
From this follows that being ready or prepared for something, or anticipating the next-to-come, is only possible for a conscious living being. Indeed, to anticipate the not-yet and to retain the no-longer is one of the most fundamental functions of consciousness."
Thomas Fuchs - Ecology of the Brain. The Phenomenology and Biology of the Embodied Mind.