In 1967, young U.S. Navy sailor Doug Hegdahl was captured during the Vietnam War after being knocked overboard from his ship in the Gulf of Tonkin and eventually ending up in the infamous prison known as the Hanoi Hilton. His captors quickly decided he was harmless, uneducated, and not particularly bright. They even gave him a nickname: "The Incredibly Stupid One." Hegdahl encouraged that impression. He pretended to struggle with reading and writing, acted confused during interrogations, and convinced his captors that he was no threat at all. Because they underestimated him, he was given more freedom around the prison than most prisoners received. That freedom allowed him to meet and quietly gather information from fellow American prisoners being held there. Knowing that names could be forgotten but songs could not, Hegdahl and fellow prisoners turned to an unusual memory aid: the tune of Old MacDonald Had a Farm. By repeating the names, details, and capture information to the rhythm of the children's song, he memorized information on more than 250 fellow prisoners. When he was unexpectedly released in 1969, he returned home and recited the names from memory, confirming that many men previously listed as missing were in fact still alive in captivity. His "stupidity" had been one of the most effective intelligence operations carried out from inside a prison camp. #archaeohistories#