<dd>But this was clearly not just a matter of the physical advantages of early humans, of erect posture and having the hands free to carry something else. Fetching branches for a fire implies that the individuals concerned thought about what they were doing, and knew why they were doing it. Keeping a fire going implies foresight and care. Wood had to be gathered, and perhaps even stored during wet periods. Such activities did not come naturally to early humans; they required learning and discipline. Especially when humans began to collect fuel over larger distances, they devoted part of their energy to maintaining something outside themselves, something beyond their own immediate needs. This is not to say they were acting `unselfishly.~ Tending the fire was a form of `deferred gratification~ or putting off the satisfaction of immediate needs in planning for future needs, like that which was later to become an essential ingredient in agriculture and livestock-raising. Unlike superficially similar complex activities such as nest-building by birds, it was not genetically determined but had to be learned. What was it that enabled early humans to control the use of fire; first to keep a fire going for an extended length of time and then to be successful in passing on this ability from generation to generation? In order to answer this question, it may be useful to distinguish between the physical, mental, and social preconditions that were necessary. them . Even before humans could make fires themselves, one of the advantages that they (and possibly other primates as well) had over other animals was that they were able to handle sticks with which they could rummage in the smoldering fire without getting burned. After a forest fire they were able to search through the ashes for food and probably noticed that they might prolong the fire's burning by throwing branches on it. Even more important, however, was the capacity to pick up burning matter and transport it to a place where it could not be extinguished by rain or wind. <p>But this was clearly not just a matter of the physical advantages of early humans, of erect posture and having the hands free to carry something else. Fetching branches for a fire implies that the individuals concerned thought about what they were doing, and knew why they were doing it. Keeping a fire going implies foresight and care. Wood had to be gathered, and perhaps even stored during wet periods. Such activities did not come naturally to early humans; they required learning and discipline. Especially when humans began to collect fuel over larger distances, they devoted part of their energy to maintaining something outside themselves, something beyond their own immediate needs. This is not to say they were acting `unselfishly.~ Tending the fire was a form of `deferred gratification~ or putting off the satisfaction of immediate needs in planning for future needs, like that which was later to become an essential ingredient in agriculture and livestock-raising. Unlike superficially similar complex activities such as nest-building by birds, it was not genetically determined but had to be learned.