ABSTRACT
We have seen that both human children and chimpanzees form an interest in beginnings and ends of linear routes and that they demarcate these important landmarks with a distinctive action or sound. Sometimes, to the young of both species the instant of impact becomes an event of interest in itself. This being so, I give this play-assembly a special term all of its own: trajectory-and-moment-ofimpact. Chimpanzees, like human infants, use special techniques to emphasise the point-of-arrival, as if exploiting this event for its expressive characteristics. Techniques used to pronounce the moment of impact may take many forms. An especially loud slap is a basic one but a range of surprisingly subtle and light caresses may also serve, as well as quite elaborate ornamentations – one example being Rah’s dropping of a piece of food and her attempt to retrieve it before it falls, all within a single beat. The use of such different kinds and complexities of actions serving as punctuation suggests that the chimpanzee adopts an overarching principle which encompasses all these forms; the principle of emphasis.
