Investigating Memory in Toddlers: Insight from Neuroimaging and Eye Movements

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Project Summary/Abstract. As infants transition into toddlerhood, their ability to remember specific details about their past improves considerably. At the same time, explicit demands to their memories become more frequent, illustrated by requests to search for lost toys or reminiscing of shared experiences. To respond with the appropriate decision (e.g., to search for a toy at the correct location), toddlers ought to integrate memory signals with their current goals. Over the past several decades, we have learned a vast amount from behavioral studies about the factors affecting memory strength and persistence in infancy and early childhood. However, relatively little is known about the neural substrates and decision processes that underlie early memory functioning. The proposed application will begin to address this gap in the literature while providing an opportunity for training in functional Magnetic Resonance Imaging (fMRI) techniques, eye tracking methods, experimental design, and repeated measures approaches utilized in developmental cognitive neuroscience research. In pursuing Aim 1, I will investigate the hippocampal contributions to early memory abilities, utilizing novelty preferences as the implicit behavioral measure of memory ability. Hypotheses predicting more hippocampal activation association with greater novelty preferences for associations learned in lab will be tested. Toddlers will learn associations between cartoon characters and a song. Memory for these associations will be assessed using a novelty preference procedure. Hippocampal activation for the songs will be measured utilizing fMRI data collected during natural nocturnal sleep. In pursuing Aim 2, I will investigate the factors affecting toddlers’ ability to make accurate memory decisions, which will provide additional training in clinical trials design per NIH designation. Specifically, three behavioral experiments will examine how manipulating toddlers’ attention to different aspects of a retrieval array affects their ability to select accurate responses. Hypotheses include predictions that toddlers’ attention will be attracted to the novel portion of the array, interfering with the ability to integrate memory signals into their decisions resulting in lower accuracy. Conversely, it is hypothesized that overt accuracy will be increased through manipulations that divert attention away from novel stimuli. Results from the studies from Aim 1 and for Aim 2 will both provide substantial contributions to theories of early memory functioning in typically and atypically developing children, and will have the potential to provide insight into future intervention efforts in educational domains.