In medical product design, function is paramount. The device must work as intended, no questions asked. Proper function is often related to operation of the device in the proper manner. Designing a medical device in a way that clearly shows the user how to operate it must employ a knowledge of cognition as a basic tool.
Each of us have developed mental models of the world that we refer to when we encounter novel situations. Our mental models guide how we perceive, think, feel, decide and act. The key to designing an intuitive medical product lies in aligning the design with the user’s mental model of similar objects and visual cues present on the device. Though each person’s mental models are different, we can address aspects of them through what seem to be commonalities of behavior among everyone. For example, certain forms, shapes, characteristics tell us how we can manipulate them: open, lift, insert, turn, etc. These characteristics are called affordances. A flat surface affords (among other things) putting things on top of. That’s why if you’re designing a sensitive lab instrument, you might want to design the top to be curved to discourage people from putting lab notebooks, tools and other things on top of the instrument.