Multimodal Output Management - Man-Machine Dialogue: Design and Challenges - page 152

linked to an underlying intention. We can give this value the importance of a
force, that is the level of intensity to which the value must be transmitted. The
way it is presented, for example a warning, depends on the illocutionary
value: if the sole goal is to give information, due to a “saying that”, the
information can be presented in a neutral manner, which will be very different
from the manner chosen for a “telling to”, which is the same as giving the
user an order to take the warning's significance into consideration, according
to an operational mode matching an “inciting to act”. The dialogue system
can require a confirmation of the message's reception. Thus, we can
distinguish an act that consists of information without any specific indication
on the rest of the interaction, an act that consists of informing by asking for
acknowledgment, which dialog boxes sometimes do by including the “OK”
and “cancel” buttons, which the user has to click on if he/she wants the task to
progress. For these two examples, the notion of act is useful, and thus shows
that automatic generation can carry out similar strategies to automatic
interpretation. The alert example can thus take on the form of a composite act
with a “saying that” clarifying the nature of the issue and a “telling to”
ordering the user to react. As the acknowledgement example, it combines a
“saying that” covering the information presented with an “asking” covering
the acknowledgement: “OK” is a positive answer to this question while
“cancel” is a negative answer.
9.2.2. Perlocutionary forces and values
These examples that incite or force the user to react in a certain way are
close to the notion of perlocutionary act that aims to have certain effects on
the user's mental states (section 7.1.1). What illocutionary values cannot
explicitly do through concrete acts, perlocutionary values can help the
system, for example the ECA, to manifest a behavior that helps to generate a
certain effect on the user. Managing a perlocutionary value is complex,
especially when it is accompanied by a certain force. In any case, it is up to
the multimedia presenter to find a form of expression for the message, which
renders the perlocutionary aim correctly. It can be a specific prosody, or an
expression or attitude on the ECA's part that expresses expectation, indicating
that it is expecting a reaction from the user. In our example, the system can
answer “I do not have any seats left on the train for Paris” to the user's
request, which is a simple “saying that” with no other perlocutionary goal
than to inform. However, the system can also answer “an hour before it