Scientists believe Torquay born novelist Agatha Christie used words that invoked a chemical response in readers that made her books "literally unputdownable".
A neurolinguistic study of more than 80 of her novels concluded that her phrases trigger a pleasure response which cause people to seek them out again and again.
According to the study Christie used literary techniques mirroring those employed by hypnotherapists and psychologists, which have a mesmeric effect on readers.
|Agatha Christie rehearsing Yellow Iris, 1937|
"Christie's language patterns stimulate higher than usual activity in the brain," Dr Roland Kapferer said.
Her grandson Mathew Prichard told The Times: "It's not really a mystery. She was simply a writer of great plots."
The Agatha Project study was carried out by scientists from universities in London, Birmingham and Warwick for an ITV1 documentary.
It involved loading Christie's novels onto a computer and analysing her words, sentences and phrases.
It might finally explain the enduring popularity of the late author, who created detectives Miss Marple and Hercule Poirot and wrote novels such as Murder on the Orient Express.
|Joan Hickson as Miss Marple|
The team found that common phrases used by Christie acted as a trigger to raise levels of serotonin and endorphins, the chemical messengers in the brain that induce pleasure and satisfaction.
These phrases included "can you keep an eye on this", "more or less", "a day or two" and "something like that".
"The release of these neurological opiates makes Christie's writing literally unputdownable," Dr Kapferer said.
Christie was also found to have used a very limited vocabulary.
"It means that readers aren't distracted and so they concentrate more on the clues and the plots," said Dr Pernilla Danielsson of Birmingham University.
They also found that Christie frequently used dashes to create "a faster-paced, unreflective narrative".
Christie is listed in the Guinness Book of Records as the best-selling author of all time and attributed with selling two billion books worldwide.
Dr Kapferer said: "Our next step is to seek to replicate these experiments with other leading authors to discover whether their writings cause similar neurological activity among readers."