Typically, the definition of behavior can be divided into two categories: observable and unobservable. Observable behavior constitutes anything that an individual does that can be measured by another individual. For example, eating, running, and reading aloud are all types of observable behaviors. The observer watches and records the occurrence of each targeted behavior of the person being observed (e.g., the number of times a student raises his or her hand), thus providing measurements of the observable behavior. Examples of unobservable behaviors are thinking, imagining, learning, reading silently, and analyzing; all of which cannot be accurately recorded and measured because they are internal events. To determine if an unobservable behavior is occurring or has occurred, individuals such as educators and psychologists often devise tests and subjective ...