Over gedrag observeren en de moeilijkheid er van, en dat het vaak 'ordinaal' gebeurt. Ook de relevantie van non-verbaal gedrag wordt beschreven. 

naturalistic observation of behavior has been an important feature of ethology

As a result, ethology has developed distinctive and powerful methods for observing and measuring behavior.

When applied to human subjects, the ethological approach involves direct observation, coding and analysis of specific nonverbal behaviors in naturalistic settings.

Rigorous description is combined with a theoretical emphasis on those behaviors that are most closely related to adaptive functioning. The behavior patterns that are observed occur as a part of the individual’s interaction with the natural environment, allowing an understanding of the relationship of specific behaviors to the capacity of dealing with real-life situations. This leads to the other major contribution of ethology to psychiatry.