A French TV show which invited contestants to give a man increasingly large electric shocks until he apparently died said it was astonished by their willingness to comply.
The Game of Death, which goes out tonight on the state-owned France 2 channel, recruited ordinary people who had no idea they were being set up.
Based on a US psychological experiment in the 1960s, the man apparently being shocked is zapped each time he gets a quiz question wrong.
Each time the show's hostess urged contestants to turn up the voltage until the man screamed in pain with the audience, who also believed the game was real, shouting "punishment" as encouragement.
Eventually the "victim" appeared to drop dead.
"We were amazed to find that 81 percent of the participants obeyed" the sadistic orders of the television presenter, said programme-maker Christophe Nick.
"They are not equipped to disobey," he added. "They don't want to do it, they try to convince the authority figure that they should stop, but they don't manage to," he told French news agency AFP.
Out of 80 players just 16 walked out refusing to administer the shocks.