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Reasoning about Interest-Based Preferences
Wietske Visser, Koen V. Hindriks, and Catholijn M. Jonker
Man-Machine Interaction Group, Delft University of Technology
Delft, The Netherlands
{
wietske.visser,k.v.hindriks,c.m.jonker
}
@tudelft.nl
Abstract.
In decision making, negotiation, and other kinds of practical reason-
ing, it is necessary to model preferences over possible outcomes. Such prefer-
ences usually depend on multiple criteria. We argue that the criteria by which
outcomes are evaluated should be the satisfaction of a person's underlying inter-
ests: the more an outcome satisfies his interests, the more preferred it is. Underly-
ing interests can explain and eliminate conditional preferences. Also, modelling
interests will create a better model of human preferences, and can lead to better,
more creative deals in negotiation. We present an argumentation framework for
reasoning about interest-based preferences. We take a qualitative approach and
provide the means to derive both ceteris paribus and lexicographic preferences.
1
Introduction
We present an approach to qualitative, multi-criteria preferences that takes underlying
interests explicitly into account. Reasoning about interest-based preferences is rele-
vant in decision making, negotiation, and other types of practical reasoning. Since our
long-term goal is the development of a negotiation support system, the motivations and
examples in this paper are mainly taken from the context of negotiation, but the main
ideas apply equally well in other contexts.
The goal of a negotiation support system is to help a human negotiator reach a better
deal in negotiation. The quality of a deal is determined for a large part by the user's
personal preferences. A deal generally consists of multiple issues. For example, when
applying for a new job, some issues are the position, the salary, and the possibility
to work part-time. For a complete deal, negotiators have to agree on the value for
every issue. The satisfaction of a negotiator with a possible outcome depends on his
preferences.
Since the number of possible outcomes is typically very large (exponential in the
number of issues), it is not feasible to have the user express his preferences over all
possible outcomes directly. It is common to compute or derive preferences over pos-
sible outcomes from preferences over the possible values of issues and a weighing or
importance ordering of the issues. One of the best-known approaches is multi-criteria
utility theory [1], a quantitative approach where preferences are expressed by numeric
utilities. Since such quantities are hard for humans to provide, qualitative approaches
have been proposed too, e.g. [2]. Our approach is also of a qualitative nature.
In this paper we argue that issues alone are not enough to derive outcome preferences.
Instead, we will focus on modelling underlying interests and their relation to issues.
