Answer:
Naturalistic observation.
Step-by-step explanation:
Psychology is the field of science that mainly deals with the study of the mental, psychological and behavioral study of the organisms. The psychology requires the proper research methodology to explain any fact.
The naturalistic observation may be defined as a type of research method used especially by psychologist to observe the research in the natural environment outside the labs. This type of research cannot be done or observe in the labs.
Thus, the answer is naturalistic observation.