Recent declassified documents from the Central Intelligence Agency have confirmed that American intelligence officials conducted early behavioral science experiments on Korean prisoners of war during the 1950s, marking the first official acknowledgment of such practices under what would later become the infamous MK-ULTRA program. The records, released between December 2024 and April 2025 by the National Security Archive, detail how personnel involved in Project Bluebird — the precursor to MK-ULTRA — sought to develop techniques for influencing human behavior through drugs, hypnosis, and interrogation methods, with specific reference to testing on North Korean detainees in U.S. Custody.
These newly available files include internal memos, budget proposals, and meeting notes that outline the scope and intent of early Cold War-era research into mind control. Among them is an April 5, 1950 memorandum addressed to then-CIA Director Roscoe H. Hillenkoetter, which describes plans for specialized interrogation teams composed of a psychiatrist, a hypnotist, and a polygraph technician. The document emphasizes the demand for strict secrecy, stating that knowledge of the project “should be restricted to the absolute minimum number of persons.” A separate budget proposal from the same period allocates $65,515 for personnel, equipment, and transportation, with $18,000 designated for operational logistics, though specific overseas locations remain redacted in the released versions.
One of the most significant revelations comes from a summary of a CIA meeting held on August 8, 1951, which explicitly notes that a team including a polygraph operator, psychiatrists, and psychologists conducted work on Korean prisoners of war in Japan. This confirms long-standing allegations first raised in journalist John Marks’s 1979 book, The Search for the “Manchurian Candidate”, which documented how 25 unnamed North Korean POWs were selected in October 1950 as initial subjects for what were described as “advanced” interrogation techniques aimed at achieving behavioral control.
While popular narratives often associate MK-ULTRA with lysergic acid diethylamide (LSD) administration and extreme psychological manipulation, the declassified materials indicate that early experiments under Project Bluebird focused on more subtle methods. These included the use of polygraph examinations, barbiturates such as sodium amytal, stimulants like benzedrine, and experimental drug delivery systems like hypospray jets — devices designed to administer substances through the skin without leaving visible marks. Internal correspondence also reveals interest in adapting unconventional tools, including modified tear gas pens and devices inspired by German wartime prototypes, for potential use in covert operations.
The documents further reveal that CIA scientists were exploring fundamental questions about human susceptibility to influence. Notes from internal discussions list specific research objectives, such as whether it was possible to induce actions contrary to a person’s moral principles, alter personality temporarily, induce reliable amnesia through chemical means, or compel someone to perform complex mechanical tasks like operating vehicles or machinery under direction. One memo from September 18, 1951, even raised the prospect of conducting hypnosis experiments over telephone lines, though officials noted that such tests had not yet received internal approval due to security concerns.
Despite widespread public belief — fueled by films and media portrayals — that American prisoners of war had been brainwashed by North Korean or Chinese forces during the Korean War, the declassified record shows no evidence to support this claim. In fact, a 1983 testimony from Sidney Gottlieb, the chemist who later oversaw MK-ULTRA operations, stated that investigations found no substantiated cases of American POWs being subjected to drug-induced hypnosis during their captivity. Gottlieb recalled that a review concluded the techniques used by opposing forces were not considered technically sophisticated and did not rely on pharmacological or neurological methods.
A 1952 memo addressed to CIA Director Allen Dulles further underscores the agency’s mindset, noting that the absence of proof regarding enemy mind-control efforts should not be interpreted as evidence of their nonexistence: “We cannot accept this lack of evidence as proof.” This reflects a broader pattern in which U.S. Intelligence pursued aggressive research into behavioral modification not only in response to perceived threats but also as a proactive strategy to develop capabilities for influencing individuals and populations during the early Cold War.
The release of these documents adds to a growing body of historical evidence about the extent and nature of U.S. Government experimentation on human subjects during the mid-20th century. While the full scope of MK-ULTRA remains difficult to reconstruct due to the destruction of many records in the 1970s, the newly available files provide concrete confirmation that experimentation began years earlier than previously acknowledged and involved populations under U.S. Detention, including foreign nationals held during active conflict.
For researchers, historians, and the public seeking to understand this chapter of intelligence history, the National Security Archive has made the full collection available online under the title “CIA and the Behavioral Sciences: Mind Control, Drug Experiments and MK-ULTRA.” The archive includes over 1,200 documents, ranging from internal memos and experimental proposals to meeting transcripts and financial records, all accessible through its digital repository. Those wishing to review the primary sources can visit the archive’s dedicated collection page, which provides direct links to each declassified file.
As with all historical disclosures involving government conduct, the release of these records invites reflection on the ethical boundaries of national security research and the importance of transparency in democratic oversight. While the programs described were terminated decades ago, their legacy continues to inform debates about accountability, human rights, and the responsibilities of intelligence agencies in open societies.
To stay informed about future disclosures or historical analyses related to Cold War-era intelligence programs, readers are encouraged to consult official repositories such as the National Archives and Records Administration, the CIA’s Freedom of Information Act electronic reading room, and trusted historical institutions like the Wilson Center or the National Security Archive.
If you found this information valuable, consider sharing it with others interested in historical accountability, government transparency, or the ethical dimensions of national security. Thoughtful engagement with the past helps ensure that lessons are learned and that similar overreach is less likely to be repeated in the future.