Which of the following is NOT a main research method used in psychology?

The correct answer is that philosophical inquiry is not considered a main research method in psychology. Psychology primarily relies on empirical methods to gather data and test hypotheses about human behavior and mental processes. Experiments, surveys, and observational studies are all structured approaches that allow researchers to collect data systematically and analyze it to draw valid conclusions.

Experiments involve manipulating one or more variables to observe their effects on other variables, providing a cause-and-effect understanding. Surveys gather information from a large number of respondents, often through questionnaires or interviews, which can yield valuable insights into attitudes, beliefs, and behaviors. Observational studies involve watching subjects in their natural environment without interference, which helps in understanding behavior as it occurs in real-world contexts.

In contrast, philosophical inquiry focuses on exploring fundamental questions about existence, knowledge, and ethics through reasoning and argumentation without the emphasis on empirical data collection that characterizes psychological research methods. Thus, while philosophical inquiry may inform psychological theory and ethics, it does not qualify as a research method used to gather empirical evidence in psychology.