Decision Dynamics in Early Numerical Estimation: Evidence from the Dual-NLET and Drift Diffusion Modeling

The present study examined the cognitive mechanisms underlying decision-making in number-line estimation in 26 preschoolers through the lens of the evidence-accumulation paradigm. Children completed a traditional Number Line Estimation Task (NLET) and the Numeracy Screener test, which assessed symbolic and nonsymbolic abilities. They also completed a novel two-alternative forced-choice version of the Number Line Estimation Task (dual-NLET), which is introduced in this study as a tool for investigating decision-making processes in number-line estimation by enabling two-choice diffusion modeling. Results showed that accuracy in the traditional NLET correlated with both accuracy and decision efficiency in the dual task. Moreover, symbolic and nonsymbolic numerical abilities were differentially associated with distinct decision-making aspects: symbolic skills correlated with decision efficiency, while nonsymbolic skills correlated with decision threshold. These findings provide new insights into the roles of symbolic and nonsymbolic numerical systems in number-line decision-making and support the utility of the evidence-accumulation approach in developmental numerical cognition research.