The BBC documentary program “Horizon” has partially replicated the landmark sensory deprivation experiments of the 1950s and 1960s. Interest in these studies has been spurred anew by recent claims that the studies were sponsored by the CIA, who were attempting to develop method of psychologically breaking down prisoners without resorting to physical torture, and that the techniques developed then are being used now in places like Abu Graib and Guantanamo Bay.

According to an article at BBC News/Magazine, six volunteers were shut inside cells in a nuclear bunker for a period of 48 hours. Three were left in total darkness. Three others were given some light, but made to wear translucent goggles and foam padding over their hands and arms. “It’s really hard to stimulate your brain with no light,” says one of the participants. Within 30 hours, most are pacing up and down their cells in an effort to generate any sort of stimulation. Some begin to hallucinate.

The psychologist who monitored the experiment explained, “In the absence of information the human brain carries on working and processing information even if there is no information to process and after a while it starts to create that information itself.”

After just 48 hours, most of the participants exhibited a “marked deterioration” in intellectual function. Of course, real prisoners are forced to endure these conditions for much longer periods of time, resulting in greater psychological effects. Brian Keenan was held as a hostage in Lebanon for four years, spending months in total isolation. “The question in your head,” he says, “is how am I going to get through the next 10 minutes?… Is there enough left in my head? I remember one occasion waking up and having to squeeze my face and my chest and thinking to myself ‘Am I still alive?'”

The documentary based on these events, “Total Isolation,” was shown on BBC Two on Tuesday, 22 January. There is a companion website where you can watch an 8.5-minute video condensation of the show.

Tip o’ the hat to Gabriel Ruiz of the University of Seville for alerting me to this program.