3) The community is the classroom. Children in hunter-gatherer societies and other traditional societies are immersed in the activities of the whole community. They witness directly all the sustenance activities. They hear first-hand the stories, conversations, and arguments of adults, and they participate, along with adults, in their culture's dances, games, and ceremonies. Because they are exposed to all aspects of their culture, they can incorporate all of the culture's relevant skills into their practice and play. They attend not just to others' actions but also to the consequences of those actions, and their observations are tinged with value judgments. Children learn what not to do from witnessing others' failures, just as they learn what to do from witnessing others' successes. They learn to emulate the most successful members of their culture—those who are best at solving life's problems and most admired by others—and to avoid acting like those who are least successful.4) Learning must be immediately reinforcing. Education has unquestionable long-term benefits, but those are generally insufficient to motivate young learners. All species, including humans, find it difficult if not impossible to learn when the costs of learning are immediate and the benefits are much delayed. In the language of behaviorists, learning requires "reinforcers"—immediate, satisfying consequences that serve as incentives. In children's self-motivated exploration and play, the reinforcers lie in the discoveries made, the immediate sense of increased skill, the pleasures of the activities themselves, and social feedback (which may be as simple as a playmate's smile). These all contribute to the joy of learning. In today's world, such skills as reading and mathematics have long- term benefits, but children eagerly engage in them only if there are immediate benefits. 5) Learning occurs best in mixed-age settings. Before the existence of graded schools, children were rarely segregated by age. Age mixing seems to be crucial for learning in hunter-gatherer and many other traditional societies. Children have more to learn from others who are older or younger than themselves than from those their same age. Young children want to emulate older children, who serve as more powerful models than adults because their skills and knowledge are closer and more attainable. In age-mixed play younger children engage in and learn from activities that would be too complex for them to do alone or just with age-mates. In the process of helping younger children, older children consolidate their own skills. As every teacher knows, we often learn more by teaching than by being taught, especially if our students freely challenge us. Older children also exercise their nurturing and leadership skills through interactions with younger ones.