Motor memory is a factor in infant perseverative errors

Why do infants make perseverative errors when reaching for two identical targets? From a dynamic systems perspective, perseverative errors emerge from repetitive perceptual-motor activity in novel and/or difficult contexts. To evaluate this account, we studied 9-month-old infants performing two tasks in which they repetitively reached toward either a single target or two identical targets. Results showed that, in the context of the two identical targets, perseverative responses were preceded by the creation of strong memories of previous reach directions and trajectories. In contrast, we found little evidence for convergence on habitual reach trajectories when the infants performed the less taxing single-target task, suggesting that the demands of reaching for two identical targets strongly constrained the reaching behavior. In total, results indicated that memories of prior movements make a critical contribution to performance in the A-not-B task and its variants.