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256 Socially Intelligent AgentsFigure 31.1.Distance between 2 agents in bilateral negotiationagents preferred to negotiate with one another and each was able to offer tochange one or more of its least important positions in exchange for the otheragent agreeing one of its more important positions.Once any pair or larger group of agents fully agrees on all positions, theyform a coalition to negotiate with agents not in the coalition or with othercoalitions. The process ends when all agents are members of a single coalitionor super-coalition (i.e. coalition of coalitions of coalitions ...). In practice, theonly simulated negotiation processes that reached a conclusion were all of thetwo-agent processes.3. Simulation ResultsThe progress of bilateral negotiation was represented by changes in the differencesof negotiating positions of two agents. These differences were measuredas the Euclidian distance between the two position strings interpreted as coordinatevectors in a 30-dimensional hyperspace. An example of the progressrepresented by this measure is given in Figure 31.2. This progress is typical ofall runs with two negotiating agents. The range of the number of cycles elapsedbefore agreement was reached was from 8 to 12 with the bulk of the distanceeliminated in the last half or less of the cycles. There was no learning for theagents to do since they had no choice of negotiating partners.Although simple negotiating strategies work well for the modelled bilateralnegotiation, they do not work at all in simulations of multilateral negotiation