Perhaps the most important defining characteristic of a human being is culture. The term culture as used here is not limited to operas, paintings, and other artistic endeavors. These are seen by anthropologists (人类学家) as examples of culture: culture itself is the customary manner in which human groups learn to organize their behavior and thought in relation to their environment. Defined in this manner, culture has three principal aspects: behavioral, perceptual and material. The behavioral component refers to how people act, especially how they interact with each other. In child rearing (养育) , for example, parents and children tend to interact in a relatively patterned fashion. Then there is the manner of perception, the ways people perceive the world. For example, parents have a limited range of ideas about how they should act, and what significance parenthood carries in the scheme of things. Finally, there is the material component of culture — the physical objects that we produce. Most of what goes into making up culture is a result of learning — modifying behavior in response to experience within an environment. Learning is practically universal among organisms. But no other organism has a greater capacity for learning than a human, or depends as much on learned behavior for its survival.While the survival of most other organisms is to some extent safeguarded by instincts, humans rely heavily on culture for their survival. People must learn how to live in a particular social and physical setting, biology playing but a minimal (最小限度的) role.The ideas and modes of behavior that constitute culture are transmitted largely by a complex system of symbols that includes language. Humans have evolved an extremely complex system of communication that is unique to our species. Without it the creation of human culture as we know it would be impossible.Question：According to the passage, the behavior of making tools for producing material objects should fall within the category of _________ component of culture.