"We moved to New Jersey when I was 4 and I liked to read a lot about China. It seemed interesting and exotic to me at the time. I read anything I could get my hands on.

"By the time I reached my early teenage years it was 'the cultural revolution' (1966-76) and there were some interesting reports coming out of China but little was actually known then."

She avidly read the dispatches of the legendary New York Times correspondent Fox Butterfield, who was at the time posted in Beijing.

"He wrote a series of articles. Some of them appeared on the front cover of the (New York) Sunday Times magazine. I just found what the images of what life was like in Beijing in the 1970s and early 1980s absolutely captivating."

She studied the Chinese language majoring in Sino-Soviet studies for her undergraduate degree at Swarthmore College in Pennsylvania. Then she went on to do a master at the University of Washington and then a PhD at Berkeley - at both universities studying under Elizabeth J. Perry, the leading Sinologist who now holds the Henry Rosovsky chair in Chinese politics at Harvard.

Thornton made her first trip to China in 1985 when her uncle, who worked on the New York subway system, gave her $500 when she graduated.

"I came from a working class background so that was an unimaginable sum of money for me," she says.

After paying for her round trip ticket to Beijing she had $100 when she arrived and it was more than enough to travel extensively for four months, taking in Xi'an, Hunan and The Three Gorges Dam.

Thornton embarked on an academic career and had spells at both the Chinese Academy of Social Sciences in Beijing and at Academia Sinica, Taipei. She progressed to become associate professor at Portland State University before moving to Oxford in 2008.

With her academic work she has examined more recently the legacy of "the cultural revolution" in China today but her main focus has been State-society relations since the birth of New China in 1949.

Thornton says people often make the presumption about China that what exists now is not the finished article and major adjustments have to be made.

"I wouldn't necessarily presume that any country has to do anything. I would say that China is no more or less stable than any other system and that all systems we are looking at are very much in a state of flux," she says.

"China is rapidly developing, moving so quickly along so many different registers, it is very often hard to keep up with what happened last month, last year, you know."

She says that even in the United Kingdom, the recent death of former prime minister Margaret Thatcher highlighted cracks in the edifice of what is seen as a long established political system.

"The recent death of Margaret Thatcher was really very interesting to me as an American because I began to see that her legacy had created certain deep fissures here in British politics.

"You do have exceptional transition periods, exceptional leaders who once they rise at a certain historical moment can shift the course of history, such as Mao Zedong and Deng Xiaoping in China."

Thornton admits there is a tendency among some China watchers to interpret what is going on in the country by just monitoring Chinese microbloggers on Weibo.