Anais do IHC'2001 - Departamento de Informática e Estatística - UFSC

Anais do IHC’2001 - IV Workshop sobre Fatores Humanos em Sistemas Computacionais 45
always able to provide contextual information about the current topic of discourse. The
persistence of information requires no effort of recall on the part of users.
We have noticed that conversation on the web is less focused. It is up to the user to
select and restrict the focus of conversation from a wide range of possibilities. On the
phone, however, the sequential nature of the channel has to been taken into account, and a
more focused discourse took place.
Moreover, the web makes it possible to carry out multiple conversations in parallel,
which is not possible on the other systems. Natural discourse itself has a sequential nature
and does not allow for such parallelism. Instead, it provides means for switching back and
forth between conversation themes and topics. On the web, however, this is not necessarily
so. The user may open several different windows and carry out a number of independent
conversations almost simultaneously, which may cause confusion and frustration to users.
We may then consider that the phone system is linear, whereas the ATM is bi-dimensional,
and the web system is n-dimensional (Figure 5). In order to avoid the undesirable side
effects of the n-dimensionality of web technology, developers may explicitly constrain the
application.
dimension
n-dimensional
bi-dimensional
linear
X
phone ATM web
X
X
environment
Figure 5: Conversation dimensions in different environments.
When it comes to references, users of a phone-banking system have not only to keep in
mind the theme and topic of conversation, but also explicitly state that they want to “go
back” to a previous topic.
In natural conversation, the whole range of recently referenced topics can be accessed
at any time. In computational systems, however, users need access mechanisms for this. Due
to the sequential nature of conversation in phone-banking systems, users may only traverse
these access structures one step in each direction: 1) choose a topic of conversation or further
constrain a topic; or 2) go back to a higher level in the structure, to a previous topic. Moreover,
sometimes it takes quite a few exchanges in order to complete the selection of the topic, i.e.,
the sentence generation follows a compositional approach. In this case, the access structure
may be too deep, and users may be caught in intermediary steps, with a yet-undefined topic,
and no present indication of what he/she has accomplished up to that point. The ATM follows
this access structure closely, but the options available at one time are usually all displayed
simultaneously on a “page”. (Sometimes users must navigate through a couple of “pages” due
to a large number of options). Depending on the amount of display space, the number of
options presented at a time can be significantly large, and thus we may avoid too deep access
structures. On the web, on the other hand, display space does not pose a considerable