Diary studies are a qualitative research method where participants record their thoughts, feelings, and experiences over a specific period. This approach allows researchers to gather in-depth insights into daily behaviors and interactions, providing a rich context for understanding user experiences. Participants typically use journals, apps, or other tools to document their entries, which can include reflections on products, services, or events. The data collected can help inform design decisions, improve user experience, and identify trends, making diary studies valuable in fields like user experience and market research.