What research method involves observing users' behaviors without verbal interaction?

Observational research is a method that involves systematically watching and recording users' behaviors as they interact with a product or service without engaging them in conversation. This approach allows researchers to collect data on how users behave in their natural environment, providing insights into their habits, preferences, and challenges. By observing users directly, researchers can gain a deeper understanding of the context in which the product is used, uncover usability issues, and identify areas for improvement, all while avoiding potential biases that may arise from verbal interactions—such as leading questions or social desirability bias.

In contrast, focus groups and case studies involve direct interaction with participants, facilitating discussion and feedback. Survey testing relies on questionnaires that solicit responses from users, often requiring verbal or written input, which does not align with the passive observational approach characteristic of observational research. Thus, observational research stands out for its focus on non-intrusive data collection through direct observation, making it the appropriate answer to the question posed.