Mechanisms of Word Learning in 2- And 3- Year Olds

Abstract

Children begin to master word learning in infancy (Bergelson & Swingley, 2012). Two memory tasks, termed explicit encoding (EE) and fast mapping (FM), are typically used to investigate word learning with children. In adults, explicit encoding, which refers to the clear and direct naming of a novel object, allows memories to be stabilized rapidly and is supported by the hippocampus. Fast mapping, which refers to the inference of a novel object by exclusion of a familiar object, recruits the much slower cortex. Interestingly, the hippocampus is late developing, meaning that younger children tend to not rely on word-learning and memory processes that are supported by the hippocampus. Both the EE and FM word-learning methods were tested with novel object-label pairs among 2-, 2.5- and 3-year olds. Because we presented younger children with more exposures to these novel pairs in both EE and FM, we predicted performance to be above chance and relatively similar across age groups and across tasks. Paired t-tests were run in order to compare children's scores (demonstrated as the percent correct choice in a two-alternative forced-choice test between two novel objects) in both EE and FM to chance. Although performance on EE exceeded chance guessing, performance on FM was more variable across age. Additionally, individual ANOVAs were run comparing EE and FM scores as a function of age. No significant differences were found in the performance in both tasks across age groups.