Four experiments examined whether verbalization can interfere with insight problem solving. In Exp 1, Ss were interrupted during problem solving and asked either to verbalize their strategies (retrospective verbalization) or engage in an unrelated activity (control). Ss in the retrospective verbalization condition were significantly less successful than control Ss at solving the problems. Exp 2 replicated the finding of Exp 1 and demonstrated that the control Ss' advantage was not due to any beneficial effect of the interruption. In Exp 3, concurrent, nondirective verbalization impaired the solving of insight problems but had no effect on noninsight problems. In Exp 4, the effect of concurrent verbalization on insight was maintained even when Ss were encouraged to consider alternative approaches. Together, these findings are consistent with the hypothesis that verbalization can result in the disruption of nonreportable processes that are critical to achieving insight solutions.(PsycINFO Database Record (c) 2016 APA, all rights reserved)