When deliberation becomes inefficient.

Dual-process theories often assume that reflective, effortful thinking yields superior outcomes relative to intuitive processing. However, many decision contexts, such as chance-based or low-stakes choices, are ones in which additional deliberation cannot improve outcomes. Across two experiments (N = 918), we examined how cognitive styles and cognitive reflection relate to cognitive effort allocation in such contexts, focusing on when continued engagement becomes inefficient. Participants completed validated measures of rational, experiential, and reflective thinking and performed lottery-style decision tasks designed to eliminate informational benefits of further deliberation. Across both studies, rationality and cognitive reflection were positively correlated but did not reliably predict behavioral efficiency. Instead, inefficiency emerged asymmetrically: experiential thinking was associated with prolonged engagement, unnecessary revision, and increased sensitivity to irrelevant cues, particularly when tasks afforded unproductive dwelling. These patterns remained after controlling for demographic factors and overlap among cognitive measures, and were robust across alternative analytic specifications. Together, the findings challenge a simple equation of reflective thinking with increased effort or slower responding. Rather than indicating that reflection produces efficiency, the results suggest that inefficiency is more diagnostic than efficiency itself, arising primarily from experiential tendencies under specific task affordances. This work refines dual-process accounts by emphasizing the regulation of cognitive effort and engagement, and by highlighting the importance of aligning effort with task demands in basic cognitive processing.