It is well established that emotional information influences perceived duration. On the basis of this together with the proposition of common magnitude estimation system, we hypothesized that the presentation of emotional faces can modulate the estimation of numerical quantity as well. The present study examined this hypothesis by investigating the effects of unconsciously presented emotional faces on numerosity estimation using number bisection task. We rendered the facial images invisible by continuous flash suppression methodology in order to measure the genuine effect of emotional information by reducing the influences of a conscious effort of emotional regulation. The results have shown that the unconscious presentation of fearful faces leads to underestimation of numerosity compared to happy and neutral faces. Further experiment has shown that the participants could not detect the presence of facial expressions directly. Together, these results indicate that perceived emotion influences numerosity judgments automatically without conscious awareness, which provides novel evidence linking emotion and quantity perception.
Keywords: Emotion; Facial expression; Number; Unconscious.