Nonsymbolic probability judgment and the role of inhibitory control: numerical distance matters

The phenomenon of “the more targets, the higher probability” often occurs when people perform nonsymbolic probability judgment tasks. However, it remains unclear whether inhibitory control is needed to overcome this intuitive bias and whether the distance between the two probabilities moderates this process. We designed a probability judgment task with large and small distances and conducted two experiments. In Experiment 1 (n = 31), participants judged which box was more likely to get the target ball in the congruent task (more targets, higher probability) or the incongruent task (fewer targets, higher probability). Participants demonstrated an intuitive bias that was affected by numerical distance. In Experiment 2 (n = 33), we adopted the negative priming paradigm and found that participants required inhibitory control to overcome intuitive bias only in small-distance tasks. These results show that inhibitory control plays an essential role in overcoming intuitive bias in nonsymbolic probability judgment and that numerical distance has a moderating effect.