Which term refers to the mental effort involved in using a product?

The term that refers to the mental effort involved in using a product is cognitive load. This concept encompasses the amount of mental effort that a person must exert to process information during interaction with a product. High cognitive load can lead to user frustration and decreased efficiency, as it may overwhelm the user's ability to understand or navigate the product effectively.

Cognitive load becomes particularly important in user experience design because it directly impacts how easily users can complete tasks. When designing interfaces or interactions, professionals strive to minimize cognitive load by creating clear, intuitive designs that allow users to focus on completing their tasks without unnecessary mental strain. In contrast, other options mention aspects of the design process and product functionality, but they do not specifically address the mental effort required by users during these interactions.