Explicit versus implicit processing of directional arrows divergently modulates estimation performance

The present study investigated how the explicit and implicit processing of arrow direction influences estimation performance across two experiments. Participants first performed either an arrow direction judgment task (Experiment 1; explicit processing) or a color discrimination task (Experiment 2; implicit processing). They then completed a two-digit multiplication estimation (TME) task, employing either a round-down (RD; e.g., approximating 32 × 64 as 30 × 60 = 1800) or round-up (RU; e.g., approximating 36 × 67 as 40 × 70 = 2800) strategy. The key findings were threefold. Firstly, across both experiments, compared with trials in which the answer positions were congruent between the direction/color processing task and the TME task (congruent condition), participants were more likely to use the matched estimation strategy when the positions were incongruent (incongruent condition). Second, also across experiments, compared with congruent condition, participants achieved higher accuracy (ACC) and shorter reaction time (RT) on the TME task under incongruent condition. Furthermore, the RU strategy was associated with longer RT than the RD strategy. Estimation ACC was higher under implicit processing condition (Experiment 2) than under explicit processing condition (Experiment 1). Third, a critical three-way interaction was observed in Experiment 1: for the RD strategy, RTs were shorter when arrows pointed right under incongruent (vs. congruent) conditions; conversely, for the RU strategy, RTs were shorter when arrows pointed left under incongruent (vs. congruent) conditions. This interaction was absent in Experiment 2. These results demonstrated that incongruent condition can enhance estimation performance by promoting adaptive strategy selection, supporting the conflict monitoring theory. The theoretical and practical implications of these findings are discussed.