Knowledge in the world

Knowledge in the head and in the world. Precise behavior can emerge from imprecise knowledge for four reasons. This can be applied to software design area. For example, we can consider the “cultural constrains” as coding convension:

1. Information is in the world: Much of the information a person needs to do a task can reside in the world. Behavior is determined by combining the information in memory (in the head) with that in the world.
2. Great precision is not required: Precision, accuracy, and completeness of knowledge are seldom reqired. Perfect behavior will result if the knowledge describes the information or behavior sufficiently to distinguish he correct choice from all others.
3. Natural constraints are present: The world restricts the allowed behavior. The physical properties of objects constrain possible operations: the order in which parts can go together and the ways in which an object can be moved, picked up, or otherwise manipulated. Each object has physical features - projections, depressions, screwtheads, appendages - that limit its relationships to other objects, operations that can be performed to it, what can be attached to it, and so on.
4. Cultural constraints are present: In addition to natural, physical constraints, society has evolved numerous artificial conventions that govern acceptable social behavior. These cultural conventions have to be learned, but once learned they apply to a wide variety of circumstances. —p55, The design of everyday things