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

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5. Concluding Remarks
Anais do IHC’2001 - IV Workshop sobre Fatores Humanos em Sistemas Computacionais
In the environments under investigation, we have observed great variations on the length of
conversations (reflected on the access structures), amount of information in each
conversational exchange, and range of topics that can be explored (amount of services
offered). For instance, our phone-banking system provided only a small subset of the
functionalities and a small subset of the information items present in the ATM and webbanking
system. We have found that, moving from the phone-banking system, to the ATM,
and then to the web-banking system, discourse goes from terse to verbose. These
differences lead to a need for diverse dialog structures to support each environment's
characteristics.
The amount of information presented at each exchange in both the phone-system
and the ATM was equivalent. As a result, the phone system could have provided as much
functionality as the ATM, except maybe due to security restrictions. Figure 4 illustrates the
amount of information provided in each environment, considering the actual and potential
amount (where potential refers not to the physically possible, but to what we find
pragmatically adequate to each environment).
amount of
information
large
average
small
P
A
A
phone ATM web
P
A
P
environment
Figure 4: Amount of information potentially (P) and actually (A) provided in each
environment.
The amount of information provided on the phone “at each exchange” is distributed in a
short period time, due to the linearity of the channel. In contrast, on the ATM and on the
web, various chunks of information may indeed be presented at once. Due to display space
limitations on the ATM, sometimes one or two navigation steps are required. On the web,
the space is virtually unconstrained. In this case, human cognitive limitations provide the
constraints, for it may be strenuous for us to be presented with every single available
alternative at once, and have to look for the desired operation or content in a large, dense
page.
Due to the high rate of speech production and linearity of the phone system, the
user had to maintain the topic of conversation in mind, making use of his/her recent
memory. This suggests that the length of conversation must be short, at risk of having the
user forget what he/she is talking about. In the ATM, it is the limited display space that
does not allow much contextual information, and users also have to make use of their
recent memory for contextualizing some of the operations. In lengthy exchanges, the topic
must be presented at strategic points in the conversation, in order to facilitate its recall in
intermediate exchanges or interaction steps. In contrast, in web banking, the system is