Drift diffusion model reveals differences between adults and children in inferential decision-making

The Drift Diffusion Model (DDM) is a theoretical approach aimed to uncover hidden variables underlying decision-making and offers deeper understanding of individual strategies. DDM conceptualizes decision processes as a ramping-to-threshold run while evidence favoring a decision is accumulated. Evidence in favour of each option accumulates over time until it hits a decision boundary, at which point the choice is made. Faster decisions could depend both on the increased speed of the ramping process or a lower threshold level. The value of both these parameters could depend on the task difficulty and individual strategy. Here we tested if DDM can capture differences in adults and children in approaching decision making driven by inferential reasoning. 83 adults (Mean age = 25±2.5) and 65 children (Mean age = 10±1) completed a six-item transitive inference (TI) task. Participants first learned the ordinal sequence of abstract images (A>B>C>D>E>F), then judged the order of all possible item pairs. Task difficulty varied with item rank distance - closer pairs (e.g., B vs. C) were harder than distant ones (e.g., B vs. E), reflecting the Symbolic Distance effect. The DDM was applied to model this effect in both groups. The DDM accurately captured participants’ strategies used to reach a decision. In adults, task difficulty mainly affected evidence accumulation speed, while in children it also involved a collapsing decision threshold over time. Despite similar decision-making mechanisms, children showed greater urgency and reduced caution, consistent with immature cognitive control linked to prefrontal cortex development.