Throughout his imprisonment, he remained in a similar state, to the extent that the Vietnamese captors believed he had some form of cognitive impairment.
When asked to write statements against the United States, he agreed, but pretended to be unable to read or write, which was believable to his Vietnamese captors.
Thinking they had someone who would be easily turned to their cause, they assigned someone to teach Brent to read. After Hegdahl appeared to be incapable of learning to read and write, his captors gave up on him. Later, he came to be known to the Vietnamese as "The Incredibly Stupid One", and he was given nearly free run of the camp.
Brent also convinced his captors that he needed new glasses and memorized the route from the prison into the city of Hanoi, where he was taken to be fitted.
During his prison stay, Brent disabled five trucks by putting dirt in their fuel tanks.When asked to write statements against the United States, he agreed, but pretended to be unable to read or write, which was believable to his Vietnamese captors.
Upon his return to the United States after his release, Bent recited the names of about 256 fellow POWs who were being searched for by the US military.
Remarkably, Bent had memorized the names by associating them with the tune of "Old MacDonald Had a Farm," which he had used previously to hum during his captivity.