Evolutionary brain changes allowing integration of cooperation and<br >life at a human level are qualitative and functional， not quantitative. Anti-<br >cipatory tool making occurred in Australopithecus before the human<br >brain had enlarged much beyond simian dimensions.<br > The crucial functional capacity that distinguishes humans is use of<br >complex symbols. Between receptor and effector systems， man has inter-<br >posed something new， the symbolic system， which permits him to respond<br >rather than react. Possibilities of response are multiplied by the chan-<br >neling of stimuli through the byways of thought， particularly language，<br >permitting levels of love， cooperation， communication， and culture un-<br >known in any other species.<br > Early man s most important possessions were tools for hunting and<br >words for communicating. Adapting to the constant novelty of the hunt，<br >ape-man became human. The primary bond between human males and<br >females was not sex， but food sharing for survival. The other human in-<br >novation of continuous female sexual receptivity further strengthened<br >family ties， facilitating sustained child care by both parents that could<br >transmit a complex culture， as well as cre~it 6 the unique human tendency<br >toward lifelong dependent possessiveness. <br >