What we see & use everyday

"The human mind is tailored to make sense of the world" -- is what Donald A. Norman had stated. The world is full of objects and things that help us with our everyday lives, whether it be technological or traditional. To make our lives easier, of course. But how many times have you felt embarrassed trying to get something to work in front of a group of strangers only to find that you have failed to get it to work?

Well-designed objects are easy to interpret and understand. They contain visible clues to their operation. Poorly designed objects can be difficult and frustrating to use. They provide no clues or sometimes false clues. They trap the user and confuse the normal process of interpretation and understanding. Alas, poor design predominates. The result is a world filled with frustration, with objects that cannot be understood, with devices that lead to error. What we should do is observe the things around us and our environment, and try to find what the problem is and solve it.

Conceptual Models
A good conceptual model allows us to predict the effects of our actions. Without a good model we operate by memory, blindly; we do operations as we were told to do them; we can't fully appreciate why, what effects to expect, or what to do if things go wrong. For everyday things, conceptual models shouldn't be complex. Scissors, pens, and light switches are pretty simple devices -- there is no need to understand the underlying physics or chemistry of each device we own, simply the relationship between the controls and the outcomes.

Visibility
By looking, the user can tell the state of the device and the alternatives for action. Looking at a door, the correct parts must be visible, and they must convey the correct message. With doors that push, the designer must provide signals that naturally indicate where to push.

Constraints
Consider a pair of scissors -- the sizes of the holes provide constraints to limit the possible fingers. The big hole suggests several fingers, the small hole only one. In other words, the designer should keep constraints in mind to prevent human/user error and define limits.

Affordances
Affordances provide strong clues to the operations of particular things. (Knobs are for turning. Slots are for inserting things into. Balls are for throwing or bouncing. When affordances are taken advantage of, the user knows what to do just by looking: no picture, label, or instruction is required. Complex things may require explanation, but simple things should not. When simple things need pictures, labels, or instructions, the design has failed.

Mapping
The relationship between two things, in this case between the controls and their movements and the results in the world. Natural mapping -- For example, a designer can use spatial analogy: to move an object up, move the control up. To control an array of lights, arrange the controls in the same pattern as the lights. Some natural mappings are cultural or biological, as in the universal standard that a rising level represents more, a diminishing level, less. Similarly, a louder sound can mean a greater amount, therefore naturally our mind thinks "raising up the control" means louder.

Feedback
Sending back to the user information about what action has actually been done, what result has been accomplished. Imagine trying to talk to someone when you cannot even hear your own voice, or trying to draw a picture with a pencil that leaves no mark -- there would be no feedback.