What pupil size can and cannot tell about math anxiety

Math Anxiety (MA) consists of excessive fear and worry about math-related situations. It represents a major barrier to numerical competence and the pursuit of STEM careers. Yet it is still poorly evaluated, mostly through self-reports. Here we sought to probe Pupil Size (PS) as a viable biomarker of MA by administering arithmetic problems to young adults (N= 70) with various levels of MA. We found that arithmetic competence and performance are indeed negatively associated with MA, and this is accurately tracked by PS. When performance is accounted for, MA does not further modulate PS (before, during, or after calculation). However, the latency of PS peak dilation could add a significant contribution to predicting MA scores, indicating that high MA may be accompanied by more prolonged cognitive effort. Results show that MA and mathematical competence may be too crystalized in young adults to be discernible, calling for early educational interventions. ### Competing Interest Statement The authors have declared no competing interest.