Main Content
Constraints give us clues on how to interact with our environment, objects, and people. There are four different kinds of constraints: physical, cultural, semantic, and logical. Physical limitations constrain possible operations/actions. For example, a large peg can’t fit into a small hole, or keys only being able to fit inserted in a particular direction. Cultural constraints are prevalent in our everyday interactions. Different cultures have their own set of appropriate social actions. For example, we know to shake people’s hands when we meet them, or give our seats to elderly, pregnant, or disabled people when the bus is full. Semantic constraints are those that rely upon the meaning of the situation to control the set of possible actions. For example, on a car, we know that when the red rear lights flash, that means that the car is braking. Lastly, logical constraints refer to the logical relationship between the spatial or functional layout of components and the things that they affect or are affected by. For example, if you are putting a faucet together and notice that 1 piece is still left when you are done, that means that you built it incorrectly and that 1 piece should be inserted somewhere.
Citation
Norman, Don. The Design of Everyday Things. Basic Books, 2013.