Computer's Tale Makes All The Write Moves

The Sunday Age

Sunday February 18, 2007

STEPHEN CAUCHI with DISCOVERY NEWS

MOST authors need a computer to write a book. Meet a computer that doesn't need an author.

Dr Rafael Perez y Perez, a computer scientist at the Autonomous Metropolitan University in Mexico City, has developed a program called MEXICA that writes its own stories.

Although there were programs in the early 1980s that wrote stories, such as Tale-Spin, MEXICA's stories are, apparently, interesting and readable.

"The program keeps a record of the emotional links between characters while developing a story, and employs its knowledge about emotions to retrieve from memory possible logical actions to continue the story," Dr Perez y Perez told Discovery News.

In an internet survey that pitted MEXICA's stories against other computerised writing programs such as Brutus and Minstrel, as well as stories written solely by a human, readers ranked MEXICA's stories highest for flow and coherence, structure, content, suspense and overall quality.

Here's a sample of MEXICA's writing skills:

Princess thoroughly observed Jaguar Knight. Then, Princess took a dagger, jumped towards Jaguar Knight and attacked Jaguar Knight. Jaguar Knight was shocked by Princess's actions and for some seconds Jaguar Knight did not know what to do. Suddenly, Princess and Jaguar Knight were involved in a violent fight. In a fast movement, Jaguar Knight wounded Princess.

While MEXICA's prose may not be to everyone's taste, it's better than Tale-Spin's efforts:

John Bear is hungry, John Bear gets some berries, John Bear eats the berries, John Bear is not hungry any more, the end.

So how does MEXICA work? The program reads characters as variables and assigns a numerical value, between -3 and +3, to emotional connections that are defined as either amorous or non-amorous. The numerical value is equivalent to the degree of emotion, with -3 being intense hate and +3 being intense love.

The program also understands story tension, such as linking the word "wounded" with tension. This too is assigned a numerical value.

Once these clusters of emotional links and tensions are established, the program begins an "engagement-reflection cycle". This involves searching a database of story actions and other happenings, called "atoms", and determining the best match for the characters' contexts for that moment. The process repeats itself again and again until the system can no longer make any matches.

At this point, the computer analyses the story for coherence and "interestingness". The program views a story as interesting when tension levels increase and fall throughout the piece.

If the program finds that the story is boring or incoherent in places, it will replace or insert atoms until a version is deemed satisfactory.

Dr Perez y Perez said programs such as MEXICA were tools and not replacements for human writers. Such programs, he said, would lead to better quality stories and books.

"Programs like MEXICA are computer models that help us to conceive, and therefore to understand, how we write stories," he said. "Thus, we can improve our capacities. In my opinion, that is the goal." -- With DISCOVERY NEWS

Get with the program

A tale from BRUTUS

DAVE STRIVER wanted desperately to be a doctor. But he needed the signatures of three people on the first page of his dissertation, the priceless inscription which, together, would certify that he had passed his defense. One of the signatures had to come from Professor Hart. Well before the defense, Striver gave Hart a penultimate copy of his thesis. Hart read it and told Striver that it was absolutely first-rate, and that he would gladly sign . . .

© 2007 The Sunday Age

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