People Don't Want to Work or Think More Than They Have To
The system doesn’t require more user work than needed. The system shows the information in little bits (progressive disclosure). Examples are shown (additionally to descriptions). The objects on the screen have right affordances; clickable things look clickable. The system doesn’t provide more features to the user than needed. Good default values are provided.
People Have Limitations
In every moment, just the indispensable information is provided in the screen. The information is easy to scan. Headers and short blocks of info or text are used. The system doesn’t require the user to multi-task. Text lines have a suitable length: people prefer short ones, but they read better with longer ones.
People Make Mistakes
The system is prepared for user errors, anticipates what they will be, and tries to prevent them. User confirmation is required before committing actions with severe results in case of error. It’s easy to undo. Errors are prevented rather than shown and corrected. Error-prone tasks are broken up into smaller chunks. If the system can correct a user error, it does so and shows what it did. The development of the interface includes several iterations, user feedback and testing.
Human Memory Is Complicated
The system is not fully based on user memories. Users aren’t required to remember things from one task to another. Users aren’t required to remember more than 3-4 items at a time.
Users’ attention is grabbed and held in the right moments; users aren’t distracted when they are paying attention to something important. The system uses different or novel objects in the interface when it wants the user to pay attention. The system doesn’t relies on users noticing every change in the interface. To grab the attention, the system uses bright colors, large fonts, beeps and tones. The system doesn’t unnecessarily distract users.
People Crave Information
The system takes advantage of users seeking (food, sex, information, etc.). The system provides more information to the users when they ask for it. The system provides enough feedback to tell the user what is going on.
The system takes unconscious processing into consideration. When users are required to commit a large action, they are first required to commit a smaller one. The system uses food, sex and danger messages properly to grab user’s attention. Pictures of people and stories are used to induce emotional responses in the users. The system uses unconscious content properly to affect users’ behaviour. The system takes users’ unconscious decisions and users’ rationalizations into consideration.
People Create Mental Models
The system takes users’ mental models into account. Tasks are designed taking previous users’ mental models of every task into account. The system matches the users’ mental model, or it teaches the users to have the right mental model of the system. Suitable metaphors are used to help users to get a conceptual model of the system. User research is done to get information about users’ mental models.
Information is grouped to help focus and avoid cluttered interfaces. Related objects are close together. Fonts are large enough and easy to read. The system takes peripheral vision into consideration; the visual environment of important objects in the interface is coherent with it. There is good color contrast; red text on a blue background or viceversa is not used. Pictures of objects are descriptive enough; usually they are better if they are slightly angled and have the perspective of being slightly above. When color is used to show things that go together, another way to show the same information is used.