When designing an interface, it is important to take into consideration what type of screen the user will be on. For example, there will be a lot more space on a desktop screen compared to a smart watch. Not only does the sizing change, but the layout and placement of the components can change. Over time individuals have comprised a number laws which should help designers make sure their interfaces work effectively.
Jakob Nielsen, a Danish web usability consultant and human-computer interaction researcher, is the co founder of the Nielsen Norman Group. It was Nielsen who first described the principle of usability that recommends the use of familiar patterns in design in order to help facilitate user experience. This is because users prefer when they are on a site that works in the same way as its mobile counterpart or other devices. According to Jakob’s Law, if this is not followed, it would damage the user experience.
In his book ‘Coordinating User Interfaces for Consistency’, Nielsen states that one of the most important aspects for usability is the consistency in user interfaces. It should apply in the individual application and across the complete digital systems of the product. It should be applied across all the different medias to form the ‘total’ user interface, not just the interfaces but also documents, videos etc. Nielsen describes how consistency can be applied on a number of different levels including the individual application, across the product family, all the products running on a specific computer and internationally (for everybody, everywhere). Consistency can be difficult to obtain and maintain, but Nielsen outlines a few methods to achieve it. One of these includes having a shared code where consistency is achieved as all the products are made with the same code to create the interfaces.
Another law within user interface design is Fitts’ Law. This states that the amount of time required for a person to move a pointer to a target area is a function of the distance to the target divided by the size of the target. It was in 1954 when psychologist Paul Fitts was examining the human motor system and found that the time required to move a target depends on the distance to it. As a result of his law, designers can now design around the idea that fast movements and small targets will lead to a greater error rate. In terms of UI and UX design, this law has led to making interactive buttons larger, particularly on mobile devices where smaller buttons would be more difficult to use.
The Law of Pragnanz suggests that when people are presented with complex shapes or a set of ambiguous elements, their brains choose to interpret them in the easiest manner possible. It can often be referred to as the law of ‘good figure’. An example of this is how people interpret the Olympic Rings, do they overlap or not? In 1910, Max Wertheimer, a Hungarian psychologist founded the foundations of Gestalt psychology when he discovered the illusion of optical movement. The Gestalt laws allow you to define the most effective design elements as it allows you to learn about human perception, which will help you find the most suitable and effective elements for the design. In terms of UX design, it is key to choose simple shapes as they will be easier to remember and interpret by the user. Similarly, by simplifying elements down, it will prevent the user getting overwhelmed with information which will in turn stop them leaving the interface.
Taking all these laws into consideration will result in a strong interface concept and design. The user will be able to work and understand what is being presented to them. While the laws may be old, the effect they provide for the users is timeless as the human psychology behind them never really changes.
Coordinating User Interfaces for Consistency by Jakob Nielsen (2014)