December 26, 2005

The Agatha Christie Code: Stylometry, serotonin and the oscillation overthruster

Agatha Christie, who died in 1976, has been in the news a lot lately. Atai Winkler's "research" for on the statistics of book titles, discussed on Language Log a couple of weeks ago, gave rise to some of the headlines, for example "Computer Model Names Agatha Christie's 'Sleeping Murder' as 'The Perfect Title' for a Best-Seller". But others reference a different piece of techno-literary sleuthing. Richard Brooks of the Sunday Times tells us, in "Agatha Christie's grey cells mystery", that "leading universities" have discovered that Christie's appeal is due to "the chemical messengers in the brain that induce pleasure and satisfaction":

The mystery behind Agatha Christie’s enduring popularity may have been solved by three leading universities collaborating on a study of more than 80 of her crime novels.

Despite her worldwide sales of two billion, critics such as the crime writer P D James pan her writing style and “cardboard cut-out” characters. But the study by neuro-linguists at the universities of London, Birmingham and Warwick shows that she peppered her prose with phrases that act as a trigger to raise levels of serotonin and endorphins, the chemical messengers in the brain that induce pleasure and satisfaction.

Some might think that this is a complicated way of saying that people like the way she writes, but I'll reserve judgment until I see how the researchers themselves put it.

Meanwhile, Russell Jackson in The Scotsman takes a different tack in "Experts solve mystery of Agatha Christie's success". Apparently "linguistics experts" have discovered that the secret is a mathematical formula:

The study was carried out by linguistics experts at Warwick, Birmingham and London universities and the results are to be revealed in an ITV1 documentary on 27 December.

Dr Roland Kapferer, the project's leader, said: "It is extraordinary just how timeless and popular Agatha Christie's books remain. These initial findings indicate that there is a mathematical formula that accounts for her success."

Again, this seems to be a complicated way of saying that Christie's success is due to identifiable properties of her writing, rather than a special intervention of divine providence in the marketplace. I haven't read the rest of the news reports, but no doubt other journalists have explained that Ms. Christie's enduring success has been shown to be an emergent property of the arrangements of atoms and molecules in the printed copies of her works.

This 12/19/2005 news release from the University of Birmingham explains more about the formulae involved: this part is apparently work by Pernilla Danielsson, a computational linguist in the Department of English:

Agatha Christie used a limited vocabulary, repetition, short sentences and a large amount of dialogue in her text according to research carried out by the University of Birmingham for ITV 1’s special Christmas programme about the author.

Dr Pernilla Danielsson from the University’s Department of English has analysed the type of words that Christie used in her detective novels to develop a better understanding of her writing style and to find out why she is the world’s best selling author. To do this she has also compared Christie’s writing to that of Arthur Conan Doyle, author of Hound of the Baskervilles.

This sounds like a plausible project in stylometry, but there's nothing about it yet in any of Dr. Danielsson's works that Google or Google Scholar can find. And the Birmingham press release doesn't mention anything about serotonin or endorphins.

I couldn't find anything about this project on the University of Warwick's web site, or various of the University of London's sites. A search for "Agatha Project" on Google Scholar and other indices of scientific and technical publications turned up only some references to a completely different "Agatha Project", an old HP expert system for diagnosing PA-RISC processor board failures.

And I couldn't find anything anywhere about Dr. Roland Kapferer, "the project's leader", unless he's the Roland Kapferer referenced here as a "film and television producer and freelance writer based in London and Sydney", with "a PhD in Philosophy from the University of Macquarie", who may also be the same as the Roland Kapferer who is the lead singer for Professor Groove and the Booty Affair. If so, then he's a sort of real-world Buckaroo Banzai: could the rest of the Hong Kong Cavaliers be somewhere in the background, measuring those serotonin levels?

The ITV1 program " The Agatha Christie Code" is being "revealed" tomorrow at 16:00, so perhaps some British readers will be able to provide additional information about this research. Who, for example, is responsible for the "neuro" aspect? How did they measure serotonin and endorphins, or is that all journalistic free association? Is there going to be a publication at some point, or was this research done exclusively for the ITV Special? And has anyone seen Penny Priddy?

So far, the "Agatha Project" shares a crucial negative feature with the Lulu Titlescorer and last fall's "infomania study": there's no publication or documentation. No equations, no published data, no fitted models, no source code. Just press releases and (in the case of Agatha) a TV program. Until what they did is documented in enough detail for others to evaluate, the press reports are the same category as Professor Hikita's Oscillation Overthruster: evocative fiction. Looking on the bright side, I guess it's nice to see some popular evocative fiction with a linguistic theme.

[Update: the BBC, vying with The Sunday Timies in earnest credulity, provides some juicy details apparently supplied by Dr. Kapferer -- a few of the specific "language patterns" which "stimulated higher than usual activity in the brain" and "triggered a pleasure response".

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.

If it weren't so obviously unethical -- and also so obviously ineffective -- I'd suggest a small experiment at your local watering hole:

You: Can you keep an eye on this while I visit the restroom?
Attractive potential new friend:     Um, OK.
You: You seem trustworthy, more or less.
A.P.N.F.: [uneasily] Uh huh...
You: I won't be gone more than a day or two.
A.P.N.F.: Visiting the restroom.
You: Something like that.

Intoxicated by potent neurological opiates, your new friend will be thenceforth be addicted to your company. Really, the BBC says so. ]

[Update: more on this here.] Posted by Mark Liberman at December 26, 2005 08:24 AM