Developmental differences in memory reactivation relate to encoding and inference in the human brain

Despite the fact that children can draw on their memories to make novel inferences, it is unknown whether they do so through the same neural mechanisms as adults. We measured memory reinstatement as participants aged 7–30 years learned new, related information. While adults brought memories to mind throughout learning, adolescents did so only transiently, and children not at all. Analysis of trial-wise variability in reactivation showed that discrepant neural mechanisms—and in particular, what we interpret as suppression of interfering memories during learning in early adolescence—are nevertheless beneficial for later inference at each developmental stage. These results suggest that while adults build integrated memories well-suited to informing inference directly, children and adolescents instead must rely on separate memories to be individually referenced at the time of inference decisions. Schlichting et al. investigate how the developing brain forms memories that support later decisions. Using fMRI decoding, they show that children and teens do not anchor new memories into existing, related ones, but rather store them separately.