Introduction to Interaction Design Principles and Processes

A common mistake in design is ignoring how people actually behave. In urban planning, "desire paths" or "social trails" are the worn paths in the grass where people choose to walk, even if a paved sidewalk was provided elsewhere. A good designer observes these behaviors and incorporates them into the design rather than fighting against them.

To achieve this, designers follow an iterative process. An iterative process means that design is not a straight line from start to finish, but a cycle of continuous improvement:

1. User Research: Understanding the user and their specific requirements through literature reviews or observation.
2. Conceptualise a Design: Developing the initial ideas and logic of how the interaction will work.
3. Implement Prototype: Creating a tangible version of the design, ranging from paper-based storyboards to digital tool-based prototypes.
4. Evaluate: Testing the prototype with users to see if it meets their needs.
5. Repeat: Using the evaluation results to go back to the research or conceptualization phase and refine the design.

Exam Tip: If asked to define the difference between User Interface (UI) design and Interaction Design, remember that UI is often considered a subset of the broader "umbrella" of Interaction Design.

Don Norman’s Design Principles

To ensure that an interaction is successful, designers rely on established principles. While many experts like Nielsen and Shneiderman have contributed to the field, Don Norman’s six principles are foundational to creating intuitive interfaces.

1. Visibility

Users should be able to see what their options are just by looking at the interface. If a user has to hunt for a "Submit" button, the visibility is low. A clean login screen that only shows login/signup options is a good example of high visibility because it avoids clutter.

2. Feedback

Every action taken by a user should trigger a response from the system. If you click a button and nothing happens, you don't know if the system is working or if it has crashed. A digital "spinner" icon indicating a page is loading is a classic example of providing feedback.

3. Affordance

Affordance refers to the relationship between an object's physical (or digital) properties and how it is used. A coffee mug "affords" holding; a pair of scissors "affords" cutting. In digital design, a button that looks "raised" affords clicking.

4. Mapping

Mapping is the relationship between a control and its effect. A perfect example is a modern stovetop where the arrangement of the knobs matches the arrangement of the burners. Similarly, a vertical scroll bar maps the movement of the bar to the movement of the page content.

5. Constraints

Constraints limit the possible actions a user can take, which helps prevent them from becoming overwhelmed or making errors. For example, a phone number field in an online form that refuses to accept letters is using a constraint to guide the user toward a successful input.

6. Consistency

Consistency allows users to apply patterns they have already learned to new situations. If a "Save" icon looks like a floppy disk in one part of an app but a checkmark in another, the user will become frustrated.

Conclusion

Interaction design is a multidisciplinary field that sits at the intersection of human behavior and technical capability. By following a user-centred, iterative process and applying fundamental principles like visibility and feedback, designers can create products that feel less like "tools" and more like natural extensions of human intent.