Project Summary/Abstract: Chronic exposure to background noise during childhood negatively impacts
language, literacy, and cognitive development, with repercussions for children’s academic achievement and
future employment potential. A putative mechanism linking noise to decrements in language and cognitive
development is that noise disrupts young children’s ability to build a vocabulary. A robust literature
demonstrates that noise disrupts the perception of spoken words primarily through energetic masking, in
which noise limits high fidelity encoding of target speech, and informational masking, in which noise taxes
cognitive processes such as attentional control and working memory. Background noise likely disrupts word
learning through similar mechanisms. Although there have been studies testing the effects of noise on word
learning, these studies are few in number and variable in methodology. The noises in children’s naturalistic
environments vary in type (e.g., environmental noise [air conditioners] and background speech), intensity
level (i.e., how loud it is), semantic content (i.e., whether the child understands the background speech), and
spatial location: factors that exert different amounts of energetic and informational masking. Additionally,
differences in cognitive and language abilities among preschool-age children likely affect their susceptibility
to the negative effects of noise. Thus, we lack knowledge about how cognitive factors interact with variations
in noise to affect word learning in young children. This is a critical gap because spoken input is the sole source
of word learning in prereaders and an important source of word learning over the lifespan. The present study
will test the time course of novel word learning in the presence of background noise that varies in type, spatial
location, semantic content, and intensity level, which are factors that influence young children’s perception of
target speech. Specifically, the noise will vary by whether it contains speech content or not (Aim 1), whether
it is co-located or spatially separated from the target speech (Aim 2), whether it contains familiar semantic
and phonetic content versus only familiar phonetic content (Aim 3), and its intensity level (Aims 1, 3). To
accomplish these aims, a large cohort of children between 4 and 6 years of age will be trained on novel word-
referent pairs across three subsequent days. This age range is targeted because children’s speech perception
is highly susceptible to the effects of noise during this time in development, and it is an important age to build
foundational vocabulary skills. Each child will be tested in one noise condition, and the noise will be
systematically changed across conditions. Through this approach, we will determine how various noise
conditions affect both the number of words learned and the phonological precision of children’s representation
of the words throughout the learning process. This work aligns with the research priorities of the Child
Development and Behavior Branch of the NICHD as we will identify how aspects of children’s environments
affect word learning, a critical process for long-term language, cognitive, and academic outcomes.