The U.S. Supreme Court has promulgated that individuals accused of crimes possess particular rights and that individuals must be informed of these rights at the time of arrest.  Moreover, the court requires that an individual be capable of reasonably understanding & legally appreciating these rights before interrogation.  Forensic psychologists conduct evaluations of accused individuals in order to ascertain the likelihood that they possess adequate intellectual and psychological capabilities.

Examples of times when accused individuals might not understand their Miranda rights include mental retardation and psychotic states.  For example, certain individuals with a low IQ might not adequately understand the gestalt of the Miranda warning—or be confused regarding the meaning of various words contained in the warning.  Other individuals may be in such a state of mental confusion or psychosis such that, although they hear the words—they do not adequately comprehend the meaning of the Miranda warning—to the degree needed in order to aptly understand and appreciate their rights to remain silent, have an attorney present, and the like.  A Miranda evaluation may involve a clinical interview, record review, psychological testing, contacting collateral sources in the case, and use of instruments specifically designed for Miranda evaluations.