The purpose of United States psychological operations (PSYOP) is to induce or reinforce behavior favorable to U.S. objectives. It can be used at the strategic, operational, also known as Psychological warfare, level or at the tactical level. Strategic psychological operations are done by government agencies other than the military, except, if delegated to the military, in major wars and at the level of theaters of operations.
Psychological operations are a subset of information operations, defined as:
Planned operations to convey selected information and indicators to foreign audiences to influence their emotions, motives, objective reasoning, and ultimately the behavior of foreign governments, organizations, groups, and individuals. The purpose of psychological operations is to induce or reinforce foreign attitudes and behavior favorable to the originator’s objectives. Also called PSYOP.
PSYOP is a subset of information operations:
The integrated employment of the core capabilities of electronic warfare, computer network operations, psychological operations, military deception, and operations security, in concert with specified supporting and related capabilities, to influence, disrupt, corrupt or usurp adversarial human and automated decision making while protecting our own. Also called IO.
Psychological operations have very diverse applications, ranging from the relatively unprovocative, such as the "mine awareness" campaign in Bosnia and Kosovo, designed to curtail civilian deaths due to land mines, to programs that have incurred criticism from various groups. Information operations includes psychological operations, but also such functions as denying the enemy of the use of their own public communications or offensive psychological operations.