Robotics Reference
In-Depth Information
what kinds of knowledge are needed by a computer program in order to
generate stories.
TALE-SPIN generated stories about the lives of simple woodland
creatures, in which a character was given a goal and then the program
developed a plan to enable the character to achieve that goal. Thus the
program simulated a small world of characters whose motivations were
generated by the real-life problems they had to solve. Meehan employed
known techniques for automatic problem solving
10
and combined these
techniques with information about how social relationships and personal
characteristics affect the way that people (and hence the characters in
TALE-SPIN's stories) persuade each other to do things.
Meehan also had to develop a text generation module suitable for
story writing, which entailed keeping track of what had happened in the
story thus far. If, for example, one of its characters was a bear that had left
his cave earlier in the story, the program would write “Joe Bear returned
to his cave” rather than simply “Joe Bear went to his cave”. Whenever an
event occurred, all of its consequences were computed, and when a goal
was stated, for example, “John wanted to visit Mary”, a corresponding
problem-solving module was called—in this case it would solve the task
of how John travels to visit Mary, possibly by creating sub-goals such as
John getting to the railway station and John catching a train to the town
where Mary lives.
Here is part of one of TALE-SPIN's best stories from the mid-1970s,
entitled “Hunger”.
Once upon a time John Bear lived in a cave. John knew that John
was in his cave. There was a beehive in a maple tree. Tom Bee knew
that the beehive was in the maple tree. Tom was in his beehive.
Tom knew that Tom was in his beehive. There was some honey
in Tom's beehive. Tom knew that the honey was in Tom's beehive.
Tom had the honey. Tom knew that Tom had the honey. There
wasanestinacherrytree.... [6]
Not exactly the stuff of which Pulitzer prizes are made, but Meehan's
work did contribute to the concept of
story grammars
. The idea behind a
story grammar is that, just as every grammatically correct sentence in our
language has a structure based on the syntactic rules of the language, so
a formal structure can be developed for story writing. This formal struc-
ture usually starts with a setting (such as John being at home), followed
10
See the section “Problem Solving” in Chapter 6.
