(Kyodo News/AP Photo)

North Korean television has been showing stunning footage of public grieving following the death of "Dear Leader" Kim Jong Il, featuring groups of men and women shaking and sobbing violently, apparently inconsolable with grief.

It looks like a kind of mass hysteria, and it's disconcerting to watch.

The images are so extraordinary that many outside the hermit kingdom are asking whether the grief is authentic, or faked by North Koreans forced to mourn by one of the world's last totalitarian regimes.

Such is the cult of personality surrounding Kim Jong-il, and the deification of his family, that the shock resulting from his death is genuine, some North Korea experts say.

"People have been taught from their earliest years to see Kim Jong Il, like his  father Kim Il Sung before him, as a God-like figure," says Mike Chinoy, senior fellow at the U.S.-China Institute at the University of Southern California and the author of "Meltdown: The Inside Story of the North Koean Nuclear Crisis."

"The whole system has been organized around the Kim cult - mass worship of the leader, propaganda telling the population that everything in life comes from the benevolence of the leader," he says. "So it is not surprising that his death is a profound and unsettling shock to most North Koreans."

Nor is it a surprise that the grieving seems to be a group activity, given the way society's relationship with the state is organized through mass rallies, sports events and dances. Add to the mix that Koreans are on the whole deeply emotional, with a strong custom of "public lamentation" at family funerals.

Yet North Koreans have little choice but to join in the highly-choreographed propaganda.

"The North Koreans know that it is in their own interest to be perceived as being emotionally distraught about the death of Kim Jong Il, and so they do what is expected of them," says Donald Gregg , a former U.S. Ambassador to South Korea. "Their own, natural emotionalism makes it easier for them to perform."

A North Korean defector and former official has described the chilling scrutiny of people's response to the death of Kim Il Sung, Kim Jong Il's father and the founder of North Korea,  in 1994.

"The party conducted surveys to see who displayed the most grief, and made this an important criterion in assessing party members' loyalty," wrote the late  Hwang Jang Yop. "Patients who remained in hospitals and people who drank and made merry even after hearing news of their leader's death were all singled out for punishment."