Psychological Operations (PSYOP, PSYOPS) are techniques used by military and police forces to influence a target audience's value systems, belief systems, emotions, motives, reasoning, and behavior. Target audiences can be governments, organizations, groups, and individuals, and are used in order to induce confessions, or reinforce attitudes and behaviors favorable to the originator's objectives. These are sometimes combined with black operations or false flag tactics.
This concept has been used by military institutions throughout history, but it is only since the twentieth century that it has been accorded the organizational and professional status it enjoys now.
The word is commonly used by governments, such as the government of the United States, who do not wish to use the term propaganda or brainwashing to refer to their own work. The word propaganda has very negative connotations, and by calling it psychological operations instead, more sophisticated methods of psychological manipulation are accurately incorporated by the terminology. This euphemism for mind control is ironically an example of psychological operations -- i.e. using psychological techniques to persuade [manipulate] a large number of people to support something that they wouldn't normally support.
The purpose of United States psychological operations is to induce or reinforce attitudes and behaviors favorable to US objectives. Dedicated psychological operations units exist in the United States Army. The United States Navy also plans and executes limited PSYOP missions.
United States PSYOP units and soldiers of all branches of the military are prohibited by law from conducting PSYOP missions in the US.(Executive Order S-1233, DOD Directive S-3321.1, and National Security Decision Directive 130.) While United States Army PSYOP units may offer non-PSYOP support to domestic military missions, they can only target foreign audiences. However, domestic Federal law enforcement agencies like the FBI are exempt from the above-mentioned law.
During the Waco Siege, the FBI and BATF conducted psychological operations on the men, women and children inside the Mount Carmel complex. This included using loudspeakers to play sounds of animals being slaughtered, drilling noises and clips from talk shows about how much their leader David Koresh was hated. In addition, very bright, flashing lights were used at night.
Within the U.S. Psychological Operations community, the correct acronym is PSYOP without the "s" at the end, as noted in FM 33-1-1. NATO references will alternately list the capability as PSYOP or PSYOPS, depending on the source's country of origin, with European countries frequently using PSYOPS as compared to the US PSYOP.