Human Interface Principles
A great user interface follows human interface design principles that are based on the way people—users—think and work, not on the capabilities of the device. A user interface that is unattractive, convoluted, or illogical can make even a great application seem like a chore to use. But a beautiful, intuitive, compelling user interface enhances an application’s functionality and inspires a positive emotional attachment in users.IOS Developer's Library
I have included a brief summary of guidelines for the Human Interface Principles, more detailed ones can be found at the IOS Developer's Library website
Aesthetic Integrity
Aesthetic integrity is how well the appearance of the interface intergrates with its function. Decorative elements should be subtle. The purpose, function and controls need to be clear and obvious.
Similarly
Is often associated with games where the task requires complete immersion. The expection of the user is that the appearance intergrates with the experience. For instance if the user is on a firing range the appearance of the controls would reflect that.
Consistency
Consistency is where the interface takes into consideration the user's previous experience. In the case of web design, users expect the shopping cart to be in the upper right hand side of the interface. They also expect links within the copy to be underlined. Is the meanng of icons consistent not just within your site but with possible previous user experience. The same functions needs to behave the same throughout the application. We need to continue to use the same convensions that are already understood by our users.
Feedback
Users expect immediate feedback when they interact with an interface. Users are an inpatient lot once they are involved with a function they need feedback if the function takes more than a couple of seconds. They need to be informed of how long an operation will last and it is always good to have a control that shows the elapsing progress.
Metaphors
When introducting objects and actions that will be new to your user use metaphors that relate to real word objects and actions whenever possible and appropiate. When users first started to learn computers with GUI it helped that metaphors were used for example:
- Desktop
- Folder
- Trash
- Windows
User Control
All actions need to be initated by the user. A course of action should be suggested not automatically happen. They should be able to stop an operation at any time. The user feels like they have more control when the operations and controls are familar.