Information Technology Reference
In-Depth Information
In some ways, human-computer interaction is quite similar to the art of
improvisational theatre. Improvisational actors have freedom to introduce
anything they like, but they are judged on the grace and cleverness of their
choices, not simply on their novelty. People can theoretically introduce
anything they like into the potential of a given human-computer activity.
Introducing new potential, especially “late in the game,” has the capacity
to explode the structure of the action. How can people be constrained to
work only with potential that is inherent in (or amenable to) that which is
already in the representational world? The problem of
constraints
is treated
later in this topic, but a key element in its solution is the deployment of
dramatic probability and causality to infl uence (indirectly constrain) what
people
think
of doing.
Causality is the connective tissue of plot.
4
In this context, causality re-
fers to the cause-and-effect relationships within the action that is being
represented. The causal relationship of an incident to the whole action
is a requirement for inclusion. Causality also determines, in part, where
an incident will be placed in the plot; causes are sometimes represented
after effects, for instance, for the purpose of orchestrating audience re-
sponse through such means as suspense and surprise. Incidents are said
to be “gratuitous” if they have no causal relationship to the whole action;
gratuitous incidents shed no light on why things have happened or why
they happened as they did. They may also be the effects of causes that
are not represented.
Gratuitous incidents have no direct bearing on the plot; for example,
there is no reason to include a scene in which Hamlet brushes his teeth.
Most of us have been annoyed by gratuitous incidents in fi lms and TV
shows, and many of us have been annoyed by the same kinds of incidents in
human-computer interactions. A convention in the world of computer-aided
4. The notion of causality contains some cultural bias; that is, the notion of cause and effect is
not so universal as Aristotle believed. Some cultures substitute temporal relations for causal
ones, for instance. Likewise, many avant-garde playwrights of the twentieth century, especially
the absurdists and surrealists, attempted to eliminate causality from dramatic structure. In the
main, however, the notion of causality is pervasive and robust enough to justify our use of it
as the basis of our theory. Of course, other theories have been formulated from the alternative
views of other cultures and philosophies.
