Which of the following is a primary characteristic of abnormal psychology?

The primary characteristic of abnormal psychology is indeed the study of mental disorders and unusual behavior. This field focuses on understanding, diagnosing, and treating various psychological conditions that deviate from what is considered typical or healthy functioning. Abnormal psychology encompasses a wide range of disturbances in thought, emotion, and behavior that impact a person's overall functioning and wellbeing.

This approach involves examining the symptoms, causes, and impacts of mental disorders, as well as exploring the various treatment options available. By analyzing these aspects, mental health professionals seek to identify patterns and develop effective intervention strategies.

In contrast, the other choices focus on areas that, while important in their own right, do not primarily represent the core of abnormal psychology. For instance, analyzing typical human behavior delves into normative psychology rather than the study of deviations. Similarly, the assessment of cognitive functioning and emotional stability pertains more to cognitive psychology and emotional psychology, respectively, rather than the specific exploration of abnormal behaviors and mental health disorders.