To mass or space? Young children do not possess adults' incorrect biases about spaced learning.

The spacing effect is the robust finding that learners have stronger long-term memory for information presented on a spaced schedule, in which learning events are distributed across time, rather than a massed schedule, in which learning events are presented in immediate succession. Despite the fact that the spacing effect is highly replicable across tasks and timescales, most adults do not believe that spaced learning promotes memory. Instead, there is a persistent "massed bias"; adults believe that massed learning promotes memory to a greater degree than spaced learning. The developmental origins of the massed bias have yet to be studied; thus, the goals of the current research were to (a) identify a developmental period in which we do not observe a massed bias and (b) determine whether metamemory is related to the onset of the massed bias. The results revealed that children (aged 2-10 years; N = 109) do not have a persistent massed bias, and the number of massed endorsements increased across the early elementary school years. Children's age predicted a massed bias, but individual differences in children's metamemory abilities were not related to bias development when controlling for age. Taken together, this work suggests that researchers will need to reconceptualize dual-process theoretical accounts of metamemory and spaced learning to explain why and how children develop a massed bias.