PROJECT SUMMARY
Early experiences lay the groundwork for later learning and have long-lasting impacts on cognitive development. Yet,
contextual memories acquired before the age of four – despite being clearly encoded and retained over shorter durations –
are notoriously absent in older children and adults. If we assume that all early memories are encoded equally well, this is
clearly a paradox, but the encoding context likely influences memory formation/retention. In fact, given that caregivers are
a highly salient stimulus and modulate young children's arousal, they may provide a context that enhances memory. To
assess the functions of early memory systems and their modulation by the caregiver, we investigate item-context memory
in toddlerhood using behavior, pupillometry via eye-tracking, and fMRI. My background in conducting awake infant/toddler
fMRI, including during memory tasks, makes me well-suited to successfully complete this task with the guidance and
mentorship of the sponsor and co-sponsor. The sponsor is a leading expert in developmental affective neuroscience and the
role of early caregiving experiences in development, and the co-sponsor is a leading expert in neurobehavioral research on
attention, learning, and memory in early life (including via pupillometry). They will support my training goals of: (1)
acquiring discipline-specific background and applied methods to investigate early caregiving as a developmental context,
(1) applying principles grounded in developmental science to strengthen methodological skills for behavioral assessment of
children, (3) learning pupillometry methods with toddlers, and (4) professional development. For the proposed project, the
first aim is to examine how a novel context associated with the caregiver modulates toddlers' arousal. We hypothesize that
arousal (operationalized as increased pupil size) will be greater for contexts associated with the caregiver vs. a familiar other
(teacher). The second aim is to evaluate and examine how a context associated with the caregiver modulates memory
behavior. Prior work has shown that learning and memory systems (e.g., hippocampus, amygdala, and medial prefrontal
cortex) are sensitive to social contexts, particularly when the social context is that of the caregiver. Thus, we predict that
toddlers' item-context memory will be enhanced when encoding occurs in the caregiver-associated (vs. teacher-associated)
context. Furthermore, we predict this effect may be mediated by toddlers' arousal during encoding. Finally, as an exploratory
aim, we will examine how the caregiver-as-context influences neural mechanisms of item-context memory in awake
toddlers. Prior work in rodents has shown that the hippocampus can encode item-context memories early in life, but this has
not been tested in humans given the difficulty of conducting awake fMRI with young children. We hypothesize that the
hippocampus will be more engaged during the encoding of item-context pairs that toddlers later indicate they remember,
and that this will be especially true in the caregiver context. Altogether, this research will advance our understanding of the
functions of memory systems in early life, with implications for why memories from infancy/toddlerhood are so sparse, and
yet early experiences (particularly those related to the caregiver) tend to have outsized impacts on development.