Increasing conflict between intuitions triggers deliberation

Despite decades of research on human reasoning, a deceptively simple question remains empirically underexplored: what makes us reason? Classical Dual Process Theories (DPTs) struggle with this question because they posit an intuitive System 1 whose outputs are monitored and sometimes overridden by a deliberative System 2. This creates a theoretical paradox: System 2 would need to both detect the need for additional processing and perform that processing, behaving like a system that triggers itself. In contrast, "hybrid" DPTs resolve the paradoxical tension by proposing that conflict between competing (System 1 generated) intuitions serves as the cue that triggers analytic engagement. Although this view has become dominant, little empirical work has attempted to manipulate the strength differential of competing intuitions to test the core prediction that, by doing so, deliberation should be triggered. We test this prediction by modifying the classic base-rate neglect paradigm in a within-participant experiment with six counterbalanced conditions (N = 263). Our design extends the classic base-rate-versus-stereotype conflict by introducing a novel source of conflict: within-stereotype conflict. We systematically vary whether the stereotypical descriptions by themselves evoke one or two competing intuitions-and manipulate whether the base-rate supports one or another stereotype-derived intuition. Increasing conflict between intuitions in this manner led to probability judgments that "neglect" the base-rate less, are less confident, and (suggesting increased deliberation) take more time to be generated. Thus, our results provide empirical support for hybrid DPTs.