Mental processes encompass all the things that the human mind can do naturally. Common mental processes include memory, emotion, perception, imagination, thinking and reasoning.
Since the human mind is constantly active, mental processes are continuously relevant and affecting or intaking events from daily life.
To a user experience designer, mental processes are of utmost importance. For example, when a designer knows the nature and limitations of a mental process, such as memory, the design will be tailored according to that mental process’s capacity.