Information Technology Reference
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W1 I would go to the Thai palace.
Wilma starts the persuasion dialogue by making a
recommendation.
B1 Burger World is right here and it looks cheap.
Bert indicates two criteria that he
values and that he believes are satisfied by Burger World
W2 The Thai Palace is also cheap, but it is a walk away.
Wilma supplies information
about the criterion satisfied by the Thai Palace. Bert increases the current and
minimum utilities of the Thai Palace to 3.
B2 Is Burger World good?
Bert seeks information about another valued criterion.
W3 No. But the Thai Palace is.
Wilma indicates a point in favour of the Thai Palace.
Bert must now adjust his utilities: while the current utility of Burger World remains
3, the maximum falls to 5. But the minimum utility of the Thai Palace is now 6, and
so cannot be bettered by Burger World.
B3 OK.
Bert now has sufficient information about both restaurants for the criteria he
values: he does not ask about licensing because that can no longer change the
order for him.
At the end of the dialogue: Bert has
UT
1
=
∅
,UF
1
=
{
licenced
}
,VF
1
=
{
goodQuality
}
,VT
1
=
{
cheap, close
}
for Burger World and
UT
2
=
∅
,UF
2
=
{
for the Thai Palace. The
utility calculations for Bert and Burger World at the end of the dialogue are shown in
Figure 1.
licenced
}
,VF
2
=
{
close
}
,
VT
2
=
{
cheap, goodQuality
}
Calculation of Utilities for Bert for Burger World at the start of the dialogue
:
Current Utility =
U
1
(
UT
1
∪ VT
1
))
=
U
1
(
{cheap, close}
)
=
w
B
(
a
2
)+
w
B
(
a
3
)
=
2+1
=
3
.
Minimum Utility =
U
1
(
VT
1
))
=
0
Maximum Utility =
U
1
(
UT
1
∪
VT
1
∪
UF
1
))
=
U
1
(
{
goodQuality, cheap, close,
licenced
}
)
=
6+2+1+2
=
11
.
Calculation of Utilities for Bert for Burger World at the end of the dialogue
:
Current Utility =
U
1
(
UT
1
∪
VT
1
))
=
U
1
(
{
cheap, close
}
)
=
w
B
(
a
2
)+
w
B
(
a
3
)
=
2+1
=
3
.
Minimum Utility =
U
1
(
VT
1
))
=
3
Maximum Utility =
U
1
(
UT
1
∪
VT
1
∪
UF
1
))
=
U
1
(
{
cheap,close,licenced
}
)
=
2+
1+2
=
5
.
Fig. 1.
Utility Calculations for Bert
This is a fairly efficient dialogue: restaurants have many attributes and so Wilma
could have told Bert many things he did not know, whereas the dialogue is able to con-
clude after Bert has received just six items of information. How is this possible? It is
because Wilma is able to infer things about Bert's criteria and current knowledge be-
yond what Bert explicitly states and asks, and so can recognise what will be relevant to
Bert's opinion. This is Grice's notion of
conversational implicature
. In [4], Grice ad-
vanced four maxims (Quality, Quantity, Relevance and Manner) intended to capture the
