Final answer:
Psychology is defined as the science of both behavior, which is observable actions, and mental processes, such as thoughts and emotions. The field encompasses various areas including cognitive, biological, and clinical psychology, utilizing empirical methods to understand and study these complex aspects.
Step-by-step explanation:
Contemporary psychology is often characterized as the scientific study of behavior and mental processes. The 'behavior' part of this definition encompasses the observable actions of both humans and animals, which are measurable and can be categorized. Such behavior includes everything from simple reflexes to more complex responses like social interactions and emotional expressions. The 'mental processes' aspect refers to the internal, subjective experiences we infer from behavior, encompassing thoughts, feelings, perceptions, reasoning, memory, and more. Cognitive psychology is integral in exploring these mental processes, with a particular focus on how people perceive, think, remember, and learn.
The scope of psychological study has broadened extensively over the years, including fields like biological psychology, which looks at the biological bases of behavior, and clinical psychology, focusing on the diagnosis and treatment of psychological disorders. The expansion of these research areas demonstrates how psychology has evolved to consider a wide array of factors influencing behavior and mental processes, applying empirical methods for a comprehensive understanding.