Seven-year-olds recall non-adjacent dependencies after overnight retention.

Becoming a successful speaker depends on acquiring and learning grammatical dependencies between neighboring and non-neighboring linguistic elements (non-adjacent dependencies; NADs). Previous studies have demonstrated children's and adults' ability to distinguish NADs from NAD violations right after familiarization. However, demonstrating NAD recall after retention is crucial to demonstrate a lasting effect of NAD learning. We tested 7-year-olds' NAD learning in a natural, non-native language on one day and NAD recall on the next day by means of event-related potentials (ERPs). Our results revealed ERPs with a more positive amplitude to NAD violations than correct NADs after familiarization on day one, but ERPs with a more negative amplitude to NAD violations on day two. This change from more positive to more negative ERPs to NAD violations possibly indicates that children's representations of NADs changed during an overnight retention period, potentially associated with children's NAD learning. Indeed, our descriptive analyses showed that both ERP patterns (i.e., day one: positive, day two: negative) were related to stronger behavioral improvement (i.e., more correct answers on day two compared to day one) in a grammaticality judgment task from day one to day two. We suggest these findings to indicate that children successfully built associative representations of NADs on day one and then strengthened these associations during overnight retention, revealing NAD recall on day two. The present results suggest that 7-year-olds readily track NADs in a natural, non-native language and are able to recall NADs after a retention period involving sleep, providing evidence of a lasting effect of NAD learning.