Problem: The study sought to determine the common set of conditions and processes necessary to improve the performance of problem-solving teams beyond the abilities of individuals. Research Hypotheses: (H1) Controlling for differences in ability, the team scores of heterogeneous teams are significantly lower than team scores of homogeneous teams. (H2) The proportion of heterogeneous teams achieving the assembly effect is significantly greater than that of the homogeneous teams. Research Method: The criterion-group design was used to contrast teams composed by information-processing preferences, as measured by the Myers-Briggs Type Indicator. Data Collection Procedures and Analysis: Four-person teams completed the Winter Survival Exercise first as individuals and subsequently in teams. Findings: Heterogeneous teams performed significantly better (p less than 0.05) than homogeneous teams on the problem-solving task. However, team composition did not significantly influence the probability of achieving the assembly effect. Conclusions/Recommendations: The role that information-processing team composition plays in improving team problem-solving quality on complex, ambiguous tasks appears uncertain. (Contains 3 tables.)