Studies by Bruce Barry and Raymond Friedman of Vanderbilt University's Owen Graduate School of Management suggest personality is less of a factor than you might think. Researchers gave subjects a personality inventory and had them participate in one of two negotiations.

In one study, buyers and sellers negotiated only the price of a commodity. Subjects with more trusting and cooperative personalities fared worse than competitive, assertive counterparts only if cooperative bargainers set low goals for themselves in advance. The bottom line: Goal levels determined relative gain more than any personality trait!!

In the other study, they negotiated multiple issues. Again personality had no effect on how well negotiators performed. Cognitive ability had a much larger effect on outcomes.

The study concluded we believe toughness matters because of the "predictable and repeated errors we make when sizing up situations and processing information." So we create a self-fulfilling prophecy that we're in a win-lose and purely competitive game rather than looking for trade-offs.

Here is a game plan to avoid these errors in thinking in your negotiations:

     1. Set high aspirations and avoid letting your own or someone's reputation or behavior influence you especially if you are more cooperative than competitive.

     2. Search for differences in preferences and use these differences to create joint gain. For example, price is only one element of the deal. Think in terms of options that may be valued differently: total contract value, monthly payments, delivery, competitive pricing.

     3. Avoid personality issues and gather information about the issues to improve your opportunities to find elements that will improve your deal.*

*Adapted from "When Tough Talk Is Beside the Point," by Hal Movius (instructor, The Program on Technology Negotiation, Program on Negotiation, Harvard Law School), first published in the Negotiation newsletter, July 26, 2010.