This research tests the hypothesis that trust is a prerequisite for the exchange of information about needs and priorities in negotiation. Bargainers who do not trust one another will fail to exchange information because they fear exploitation. Aspiration level and trust were manipulated in a simulated bargaining task. Bargainers induced to trust each other exchanged high levels of information about their profit schedules, but only when instructed to achieve high profits. Low trust led to high levels of competitive behavior under the same high aspiration conditions. A general conclusion of the study is that in mixed-motive situations, people tend to match each other's levels of cooperation to the extent that they feel mutually dependent, and to mismatch levels of cooperation to the extent that they feel independent. (Author/NG)