Which design technique helps to understand user mental models and terminology?

Card sorting is an effective design technique used to gain insights into users' mental models and the terminology they prefer when organizing content. This method involves having users categorize and prioritize information or items based on their understanding and logic. By observing how users group items, designers can identify patterns in their thought processes and the language they use, which can greatly inform the structure and labeling of content in a user interface.

This technique is particularly valuable because it reveals how users perceive relationships between different pieces of information, allowing designers to create more intuitive navigation and information architecture that resonates with the user's expectations and language. The outcome of card sorting activities can direct decisions about categorization, menu structures, and the overall organization of a product, leading to improved usability and a better user experience.

In contrast, the other options focus on different aspects of the user experience. A/B testing compares two versions of a design to see which performs better, but it does not uncover users' mental models. Affinity diagramming organizes ideas or data based on themes but does not specifically probe into user terminology or mental frameworks. Customer journey mapping illustrates the user’s experience over time but is more focused on actions and emotions rather than understanding how users think about and categorize information.