Long-Term Memory in Infancy. Electrophysiological and Behavioral Measures of Declarative Memory in 14-Month-Olds.

Abstract: This paper presents a pilot study investigating the development of declarative memory in infancy, by creating a stimulus material appropriate for recording Event-Related Potentials (ERPs) during memory encoding. The material was designed to establish associations between pictures, and a negative component with a fronto-central distribution (Nc) was studied as a reflection of learning. In addition an established test of declarative memory, deferred imitation (DI), was performed in order to serve as a behavioral correlate. Information concerning general development was also collected, including an assessment of productive vocabulary as measured by the Swedish version of the MacArthur Communicative Developmental Inventories. The participants were 23 typically developing 14-month-old infants. DI data from all participants was analyzed and correlated with other developmental measures. A strong positive correlation was found between productive vocabulary and DI performance. Five participants generated data for ERP analysis, which revealed the expected Nc component but failed to show the predicted patterns. This may be explained by the current presentation of the stimulus material not making the associations clear to the infants. Suggestions for improvements of the ERP design are discussed.