The A-not-B Error: Object Permanence and Infant Working Memory (2D Field Model)

Between roughly 8 and 12 months, infants pass through one of the most famous demonstrations in developmental psychology: shown a toy hidden repeatedly at location A, then watched it hidden at a new location B, they often still reach back to A. This 2D canvas simulator models that classic Piagetian "A-not-B error" as a pair of competing dynamic-neural-field nodes — one per hiding location — numerically integrated every frame following the working-memory-plus-habit account developed by Adele Diamond and formalised as an activation field by Esther Thelen, Gregor Schöner and colleagues. Adjust the simulated infant's age, the delay before it is allowed to search, and how many times it previously found the toy at A, then run trials and watch the two live activation traces and their memory-trace inputs race to decide — correctly at B, or perseveratively at A — exactly as real infants do in the lab.