Answer:
laboratory observation
Explanation:
According to my research on different research methods, I can say that based on the information provided within the question the most appropriate method of study in this situation would be a laboratory observation. This is because this method is the most efficient method, mainly because it would allow for special equipment to measure the physiological changes. Another good method would have been a naturalistic observation, but since the Professor wants to measure psychological changes and not observable changes this will not suffice.
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