Don Norman’s Design Principles

Visibility

The more visible functions are, the more likely users will be able to know what to do next. In contrast, when functions are “out of sight,” it makes them more difficult to find and know how to use.

Feedback

Feedback is about sending back information about what action has been done and what has been accomplished, allowing the person to continue with the activity. Various kinds of feedback are available for interaction design-audio, tactile, verbal, and combinations of these.

Constraints

The design concept of constraining refers to determining ways of restricting the kind of user interaction that can take place at a given moment. There are various ways this can be achieved.

Mapping

This refers to the relationship between controls and their effects in the world. Nearly all artifacts need some kind of mapping between controls and effects, whether it is a flashlight, car, power plant, or cockpit. An example of a good mapping between control and effect is the up and down arrows used to represent the up and down movement of the cursor, respectively, on a computer keyboard.

Consistency

This refers to designing interfaces to have similar operations and use similar elements for achieving similar tasks. In particular, a consistent interface is one that follows rules, such as using the same operation to select all objects. For example, a consistent operation is using the same input action to highlight any graphical object at the interface, such as always clicking the left mouse button. Inconsistent interfaces, on the other hand, allow exceptions to a rule.

Affordance

This term is used to refer to an attribute of an object that allows people to know how to use it. For example, a mouse button invites pushing (in so doing acting clicking) by the way it is physically constrained in its plastic shell. At a very simple level, to afford means “to give a clue” (Norman, 1988). When the affordances of a physical object are perceptually obvious it is easy to know how to interact with it.

Design Principles

Design principles are used by interaction designers to aid their thinking when designing when designing for the user experience.They are general principles that help designers think about different aspects of their designs.

Visability

  • The more visible functions are, the more likely it is that users will be able to know what to do next.  When functionas are out of sight, it makes them more difficult to find and know how to use.

Feedback

  • Feedback involves sending back information about what action has been done and what has been accomplished, allowing the person to continue with the activity (imagine trying to play a guitar that has a two second delay between strumming a chard and making a noise). Various kinds of feedback are available for interaction design – audio, tactile, verbal, visual and combinations of these.

Constraints

  • Refers to ways of restricting the kinds of user interaction that can take place at a given moment.  A common design practice in graphical user interfaces is to deactivate certain menu options by shading them gray, therby restricting the user only to actions permissable at that stage of the activity.

Consistency

  • This refers to designing interfaces to have similar operations and use similar elements for achieving similar tasks.  A consistent interface is one that follows rules, such as using the same operation to select all objects (e.g. left mouse button selects object).  The benefits of consistent interfaces is that they are easier to learn and use.  Consisteny works well for simple interfaces but become trickier for more complex interfaces.

Affordance

  • Refers to an attribute of an object that allows people to know how to use it (e.g. a mouse button invites pushing by its unique shell – you can only p[ush it or click it).  At a simple level afford means “to give a clue”. There are actually two kinds of affordance – perceived and real. Real affordance relates to physical objects that perceptually obvious how to use (a door handle affords pulling, a cup handle afford grasping).  But perceived affordance can relate to interactive website where the interaction is not real but the notion of affordance helps the user.  For example, graphical elements like buttons, icons, links and scroll bars should make it obvious what should be doine with them.  Icons should be designed to afford clicking, buttons to afford pushing.

Findability

  • Refers to the degree to which a particular objective is easy to discover or locate.  Imagine the internet without away to find website information…no google!