Which of the following methods indirectly observes user behavior?

User diaries are a method that allows researchers to gather insights into user behavior by having users record their own experiences, thoughts, and activities over a certain period of time. This method permits the collection of data in an organic and continuous manner, giving users the opportunity to reflect on their interactions in real time.

By analyzing the entries in user diaries, researchers can infer patterns, preferences, and behaviors that might not be captured through direct observation or structured interactions like interviews and surveys. This indirect method can yield rich qualitative data that reflects the user's perspective, providing valuable context to their habits and motivations that might be overlooked in more structured environments.

Surveys, direct observations, and interviews primarily involve direct engagement with users, focusing on immediate feedback or observed actions. In contrast, user diaries collect data over time and from the user's standpoint, allowing for a more nuanced understanding of behavior outside the confines of observational or interrogative approaches.