Some pre-existing knowledge about human cognition can contribute to usability theory. Although frequently known as a subsection of human factors theory, some work has been done to align the human thought process with usability. In a report titled “The Role of Psychological Theory in Usability Inspection Methods,” Cathleen Wharton and Clayton Lewis from the University of Colorado, Boulder provide an overview of concepts in psychology that are at the foundation of Usability concepts used to shape technological design. The following are five broad groupings that their main points can be organized into.
Visual/Audio
- “Some things are easier to see or hear than others”
- “Some things don’t look or sound the way you would think”
- “Only some of the contents of a complex display are likely to be seen”
These three factors concern how human beings may perceive certain things through the senses of hearing and sight. The article discusses the impact that contrast, movement, size, color, and organization can have on a display and how these factors affect the interpretation by a user. For a simple example, using a dark color font on a dark color background can render a website unusable. This is further complicated by the fact that monitor saturations may differ, so what may look readable on what computer may not be on another. Therefore, it is better to have the clearest contrast possible. The root of this problem can be tied to human cognition and the way the eye interprets color and contrast. This is the type of human factor that impacts the visual/audio category.
Speed
- “Precise movements take longer than gross movements”
- “Mental operations take time”
- “People can perform some mental and physical operations in parallel.
- “People get faster the more often they perform a task”
These factors consider the impact that matters of time have on how usable a particular site is. The first is referring to the impact that the placement and size of buttons can have on the user experience. If the distance between buttons is too great or the buttons are too small, they will take more time to use, making the site less efficient. The second two factors point to the importance of comprehending your user’s capabilities when making a website—appropriate estimations of the amount of time they need to complete a certain process or their ability to multitask certain actions can allow a web designer to modify the site to suit the normative time estimates.
Knowledge
- “Novice users may perform tasks differently than expert users.
- “It takes time to learn things well”
- “Prior knowledge can be beneficial”
This group of factors is based on the impact that prior knowledge of a user has on the way they approach their use of a particular website. The category also refers to the knowledge that informs the design of a website. For example, the first factor describes how expert users perform tasks differently than novice users. Generally, those designing the site are expert users and therefore design for others with the same body of knowledge as them. However, those using the website may be coming from a myriad of levels of experience, including first-time and intermediate users. Psychologically, they may be compelled to navigate the site in a different manner and this can cause the site to be less usable for them.
Memory
- “Recognition is easier than recall”
- “People forget things”
These two concepts are very powerful in shaping design related to the human capacity to remember things. The first discusses the fact that human beings can more easily recognize things when they see them rather than having to independently pull something from their memory in order to access it. This also ties into the human ability to visually connect images with concepts they have in their mind, and how it is more powerful than their ability to enter specific terms from memory. The second concept used the example of the usability of help systems and the fact that they are more effective if the user can see them at the same time as they are performing the actions. Otherwise, the user is expected to recall the actions they were told to take and they could easily forget their next step and have to backtrack.
Intention
- “Behavior is often guided by goals”
- “Alternative methods can cause problems”
- “People try to assess progress”
This is the final factor, which relates mainly to goal-oriented web use. When the user comes to the web to perform a specific task, they want to be able to accomplish it and they will also tend to rate their ability to get closer to their goal. This category also encompasses the need of designers to clearly and accurately label the options available to a user, because users will select the option that they believe will get them closer to their goals. This concept is referred to as “label-following”. The second factor mentioned above stems from the idea of label-following—options take time. The more options a user has, the more time it will take them to determine which will lead them to their desired goal. It could complicate things and actually make the site more inefficient, allowing the user multiple opportunities to go down the wrong path. Finally, the last factor refers to the fact that, if a user cannot determine how close or far they are from their goal, they may abandon the website. Therefore, designers should provide mechanisms for users to be aware of their relative progress.
Overall, these factors describe the important aspects of human nature that impact the human-technology interaction.