Controlling narrative time in interactive storytelling

Narrative time has an important role to play in Interac-
tive Storytelling (IS). The prevailing approach to control-
ling narrative time has been to use implicit models that
allow only limited temporal reasoning about virtual agent
behaviour. In contrast, this paper proposes the use of an
explicit model of narrative time which provides a control
mechanism that enhances narrative generation, orchestra-
tion of virtual agents and number of possibilities for the
staging of agent actions. This approach can help address a
number of problems experienced in IS systems both at the
level of execution staging and at the level of narrative gen-
eration. Consequently it has a number of advantages: it is
more flexible with respect to the staging of virtual agent ac-
tions; it reduces the possibility of timing problems in the co-
ordination of virtual agents; and it enables more expressive
representation of narrative worlds and narrative generative
power. Overall it provides a uniform, consistent, principled
and rigorous approach to the problem of time in agent-based
storytelling. In the paper we demonstrate how this approach
to controlling narrative time can be implemented within an
IS system and illustrate this using our fully implemented IS
system that features virtual agents inspired by Shakespeare’s
The Merchant of Venice
. The paper presents results of an
experimental evaluation with the system that demonstrates
the use of this approach to co-ordinate the actions of virtual
agents and to increase narrative generative power.