Stop Hiding My Controls: Hidden Interface Controls Are Affecting Usability

Summary

Authors: Philip Kortum In the early 1960s, Douglas Engelbart [1] first introduced the notion of "knowledge in the world" versus "knowledge in the head" for computer interfaces—an idea that was later formalized and popularized by Donald Norman in his seminal book The Psychology of Everyday Things. From an interface design standpoint, knowledge in the world simply means that the controls you need are visible, and the identification and operation of these controls can be done through recognition rather than recall. Drop-down computer menus on modern graphical user interfaces, as shown in Figure 1, are a good example. Users don't have to memorize the command or even its specific location. Rather, they can browse through the menu command structure until they find the control they want to use. Figure 1. Drop-down menus provide the user with knowledge in the world. It is clear what the user can do in this command window. By contrast, knowledge in the head means that the user must memorize the necessary commands and controls for the operation of a specific device. In a bygone era many, if not most, computing tasks required significant knowledge in the head. You had to know the syntax or the command language to perform even rudimentary tasks. For example, determining what files were on your computer required you to have specific knowledge in the head to perform that task. If you were using a DOS-based system, you had to know the command was DIR, and that if you switched systems, the command was likely different. These kinds of systems were the ultimate hidden controls, as you needed to have complete knowledge in the head to accomplish anything (Figure 2). Figure 2. A DOS command window. Without specific knowledge in the head, the user cannot perform a single action. Insights → As interface complexity has increased, more controls are being hidden from the user. → While these hidden controls make the interface look easier to use, they actually make the interfaces much harder t...