What type of research involves studying behaviors indirectly through materials?

The choice of content analysis is accurate because this research method specifically focuses on examining and interpreting various forms of materials, such as texts, media, or documents, to understand the underlying behaviors, themes, or patterns. Researchers utilize content analysis to analyze not just the content itself, but also the context and implications of that content in relation to behaviors or social phenomena.

Content analysis can facilitate insights into how certain issues are represented in the media or how attitudes can be inferred from written documents. This method is particularly valuable in psychology since it allows researchers to examine behaviors without direct observation or interaction, thereby providing a more nuanced understanding of the subject matter.

In contrast, experimental research typically involves manipulating variables to observe effects on behavior directly, while qualitative research often relies on direct interaction, such as interviews or focus groups, to gather insights. Survey research, on the other hand, relies on self-reported data from participants rather than analyzing existing materials. Each of these other methods engages with data in a different manner than content analysis, reinforcing why content analysis is the correct choice for this question.