Contrary to the popular belief that collaboration brings better problem solutions, empirical studies have revealed that interacting groups often performed worse than noninteracting "nominal" groups. Past studies mainly examined how overhearing others' ideas impacts group performance. This study investigated the impact of another essential but overlooked group communicative process-verbalizing ideas to others-on group performance. Participants (N = 156) solved 20 verbal puzzles either alone quietly, alone thinking-aloud, or in verbalizing pairs. Participants in the same working-alone condition were randomly paired to form nominal pairs and their pooled performance was treated as nominal group performance. Relative to the quiet nominal group, the performance of the thinking-aloud nominal and interacting groups were impaired to similar extents. These two groups also demonstrated a similar limited capacity to expand the search scope. The equivalency of the interacting and thinking-aloud nominal group results suggest that verbalization is a key factor in groups' inferior performance. (PsycINFO Database Record
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