Empirical Studies in Computer-Mediated Interest-Based Negotiations Sohan Dsouza MSc IT, 2009 British University in Dubai

Study Focus Bilateral repeated negotiation under incomplete information Strategic role of goal information Effect of goal revelation on human negotiation strategy

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Contributions Design of interest-based protocol for incomplete goal information, goal inquiry and goal revelation First study to investigate outcomes and human use of goal revelation in task settings Comparison of human negotiation strategies between position- and interest-based negotiation

Significance For Multi-Agent Systems For Decision Support Systems For Cognitive Science For Psychology

Topics in Negotiation Issues and Outcomes Task Dependency Distributive vs. Integrative Position-based vs. Interest-based Multi-Agent System vs. Human

Related Work Interest-based negotiation specific to domains (Loewenstein et al., 1989) Pre-negotiation goal framing (Loewenstein and Brett, 2007) Position-based agent vs. human negotiations (Lin et al. 2008; Bosse and Jonker, 2005) Human caution with information privacy (Heiskanen et al., 2001)

Colored Trails - Platform Multiplayer client-server platform Board of colored tiles Traversal by expending colored chips Icons representing players and goals GUI and decision support tool for human players

Colored Trails – Relevance Tiles analogous to different tasks Chips as different resources or abilities used to complete tasks Traversal route represents candidate task sequence towards goal Multiple paths to goal possible Information on opponents can be hidden or revealed

Protocol Design - PBN Proposer A Responder B Responder A Proposer B MAKE PROPOSAL REJECT ACCEPT REJECT ACCEPT Position-based Negotiation (PBN) Protocol Turn-based play Rejections switch roles

Protocol Design - IBN Proposer A MAKE PROPOSAL REJECT ACCEPT REJECT ASK FOR GOAL MAKE PROPOSAL ASK FOR GOAL Responder B Responder A Proposer B ACCEPT REVEAL GOAL Interest-based Negotiation (IBN) Protocol Can ask for goal only in response to offer Can reveal goal only when asked

Game Setup 5x5 tile layout, 7 chips assigned At most one player can independently reach their goal Chip assignment allows for at least one player to get to goal by trading Only one shortest path possible Scoring function favors resource conservation and gives partial credit

Experimental Setup Masks and GUI changes to control information visibility and actions Single game settings pool shared across both negotiation protocols 4 communication minutes per game, else default to existing assignment Each player anonymously plays each other player once, in both initial roles

Results - Performance Average benefit for players in IBN/PBN conditions for different number of goal revelations (significant difference in bold) Average benefit for players in IBN/PBN conditions for different player dependencies (significant difference in bold)

Results - Agreement Pair-wise agreement ratio Agreement frequencies by task dependency

Results – Goal Revelation IndependentDependentBoth Goal Revelations16 (27%)43 (73%)59 (100%) Revelation/Solicitation16/26 (62%)43/50 (86%)59/76 (78%) Goal revelation distribution and frequency

Discussion Adapted platform robust and flexible Humans show unexpected trust in volunteering goals when asked Self-sacrifice observed on the part of independent players Possible cautionary generosity on the part of dependent players

Future Work Comparing to games with initially complete information Allowing players to reveal goals without being asked Allowing more than one shortest path Removing anonymity and having repeated games between players Building classifiers using the data

Conclusions Asked, humans generally reveal goals Both altruistic and satisficing outcomes observed in IBN Agreement likelihood and social benefit higher in IBN Strategic benefit of goal information varies with task dependency Precedent for future work on goal revelation in mediated IBN scenarios