# Can Social Agents Efficiently Perform in Automated Negotiation?
## 1 Introduction  
Automated negotiation is an iterative and distributed search process between multiple intelligent agents exchanging offers, with the goal of finding a mutual agreement that allows for cooperation between the different parties [1; 2; 3; 4; 5]. The applications of automated negotiation range from electronic commerce [6; 7], coordination in robotics [8], energy markets [9], computer networks [10], video games [11], and even traffic control [12]. Despite the large and growing body of literature about automated negotiation, there are still challenges and issues to be solved. Open multi-agent systems are systems where heterogeneous agents may enter and leave the system [13; 14]. Consequently, one may face a variety of agent behaviors when interacting with other agents in the system. This heterogeneity precludes agents from assuming a fully cooperative behavior by other agents, and it forces agents to do their best effort to try to achieve a good performance and to guarantee high utility. Therefore, in negotiation scenarios, agent designers have focused on developing the best performing agent among all competitors, that is, the agent that obtained the best utility for itself [15], with less focus on the utility achieved by its opponent. While achieving a high utility for itself is an interesting property for an automated agent, it may not be the best strategy in an agent society [16], where agents may need to collaborate on multiple occasions. For instance, an agent may act selfishly, may obtain the maximum utility for itself, andmay exploit the opponent, ending up in an agreement that may portray a low utility for its opponent. In that case, what would be the incentive for the opponent to collaborate with us? One should take into consideration that, in an agent society, agents may share opinions about their counterparts. This may make it difficult for selfish agents to collaborate with other agents in the future. As a result, this may harm the agent's long-term interests. Although an agent may need to achieve the best utility for itself, it cannot ignore the utility achieved by its opponent. Therefore, one may be tempted to think that the solution to this problem is for all agents to take a fully cooperative approach to negotiation. In the past, there have been proposals of negotiation models and strategies that assume cooperative behaviors during the negotiation. In many of these proposals, the authors assume either that both parties play the same cooperative strategy or that the other party also employs a cooperative strategy [17; 18; 19; 20]. While this is a feasible assumption in some domains, it is not appropriate for open environments where agents may display a plethora of behaviors and strategies. Previous works have shown how social or cooperative agents may be exploited by competitive agents [15; 21; 22]. Ideally, a good balance should be struck between both taking a social attitude and preserving one's own utility. In open environments, one may negotiate with a wide range of strategies, and a social agent should be prepared to attain mutually attractive utilities independently of the other agents' attitudes. The hypothesis that we aim to answer in this article is whether we can design a social agent that performs well against a wide range of opponents in an open and dynamic society. Several difficulties hinder the design of such an agent, as we discuss in the following paragraphs. First, agents should reach a consensus before their deadline, and that typically entails some type of reciprocal concessions. Constant and timely concessions regardless of the opponent's moves mostly end up in situations where the agent can be exploited, such as the case of ANAC2011 [23; 24], where the Hardheaded agent [25] won the competition by just waiting for its opponents' concessions. When the opponent concedes, a social agent should reciprocate to some extent to build a good long-term relationship and to encourage further cooperation.