What is the technique called where a participant describes his or her thought processes during an activity?

The technique referred to as "thinking aloud" involves a participant verbally expressing their thoughts, reasoning, and feelings as they engage in a specific activity or task. This approach is particularly valuable in user experience research, as it provides insights into the user's mental processes and decision-making strategies. By articulating their thoughts in real-time, participants help researchers understand how they interpret information, navigate interfaces, and encounter challenges. This technique is essential for identifying usability issues and understanding the user experience, which can inform the design process for products or services.

In contrast, reflective interviewing focuses on gathering participants' reflections after a task has been completed, which may lead to less immediate insight into their thought processes. Cognitive mapping is a technique used to visualize the relationship between concepts or ideas, not to capture real-time thinking. Participatory design involves users in the design process collaboratively but does not specifically concern itself with participants verbalizing their thoughts during an activity. Each of these methods serves a unique purpose, but "thinking aloud" is specifically aimed at capturing the dynamic and immediate thought processes of users as they interact with a product or service.