In this chapter we reviewed early and contemporary research on the effects of individual differences—personality traits and abilities—on negotiation. Early research found clear and simple effects to be elusive. In many cases, the research methods were inadequate to allow personality differences to emerge; in other cases, personality differences were obscured by major structural differences in the bargaining situation (the nature of the bargaining problem, relative power of negotiators, constituency pressures, etc.), or personality and structure interacted to produce complex effects.

More recent studies have overcome some of these liabilities. We discussed several aspects of personality that have some promise for characterizing differences among negotiators, including conflict management style, social value orientation, interpersonal trust, self-efficacy, locus of control, self-monitoring, Machiavellianism, face threat sensitivity, and the Five-Factor Model. We then examined the role of abilities in negotiation, including cognitive ability, emotional intelligence, and perspective-taking ability. There is some evidence that smarter negotiators (higher cognitive ability) are better able to find and exploit integrative potential. Although empirical evidence on the role of emotional intelligence in negotiation is still emerging, there is reason to believe that emotionally intelligent negotiators may have some strategic advantages. Research links perspective-taking ability to the development of integrative outcomes, although the underlying process through which this occurs has not been clearly illuminated.

We also explored a behavioral approach to studying individual differences was also examined. Rather than searching for underlying personality dimensions, this approach concentrates on describing how expert or accomplished negotiators behave and compares it with the actions of less experienced or less effective negotiators. Research using this approach has the potential to provide unique information about how people can learn to negotiate more effectively.

Although the study of individual differences continues to pose significant challenges, we see a future for research in this area. Researchers must be careful, however, to measure differences rigorously and to analyze behavior across diverse negotiation situations. Positive trends in research on individual differences include a focus on how personality effects vary depending on situational factors (also called the interactionist approach; see, e.g., Cantrell and Butler, 1997; Ohbuchi and Fukushima, 1997) and movement beyond the study of simple distributive negotiation tasks to consider more complex integrative situations (e.g., Barry and Friedman, 1998; Kray, Thompson, and Galinsky, 2001).

We noted at the outset of Chapter 14 (on gender and negotiation), and again in this chapter, that some researchers are skeptical about the importance of individual differences. Although the concerns are legitimate, we believe that some may have closed the book prematurely on the effects of individual differences on negotiation and that individual differences can have an important effect on the process and outcome of negotiation. It is true that negotiators cannot "change" their personalities or other stable individual differences, but they can learn to compensate for the limitations these characteristics might bring and to capitalize on behavioral tendencies that may follow from the characteristics of other parties. Moreover, constituencies and organizations frequently make choices about who will negotiate on their behalf; in these circumstances, individual differences can play an important role in negotiator selection.