Answer:
naturalistic observation; survey
Explanation:
Naturalistic observation: In psychology, the term naturalistic observation is defined as a research method that is being used by social scientists and psychologists. The psychologists who are conducting the naturalistic observation generally observe the participants in their natural environment.
Survey: In psychology, the term survey is defined as one of the research methods that involve collecting data from the participants being studies by asking various questions in person, phone, paper, or online.
In the question above, Chan-ju's study is an example of naturalistic observation and Lucas's study is an example of a survey.