Word Learning and Brain Maturation Contribute to Vocabulary Variability Amongst low SES Children

• In Event: 1-208 - The Neural Basis of Word Learning

Integrative Statement

Background. In the US, over 41% of children are from low socioeconomic status (SES) households. On average, these children have significantly worse vocabularies than their higher SES peers, which is often attributed to differences in the quantity and quality of language in the home (Hoff, 2013; Hirsh-Pasek et al., 2015). Importantly, within this population there is substantial variability, with a portion of low SES children performing as well or better than their higher SES peers on vocabulary tasks (Hackman & Farah, 2009). Here we focus on the process of word learning from context as a potential key to understanding why some children from low SES homes have stronger vocabularies than others. We address two questions: 1. Does the ability to learn new words from context predict differences in vocabulary size for children from low SES homes? and 2. are there differences in resting state EEG (a measure of brain maturation) between children from low SES homes who are strong versus poor word learners?

Methods. Thirty low SES (based on maternal education) children (ages 8-15 years) completed measures of vocabulary (PPVT), working memory (digit span), reading comprehension (GORT), and a word learning from context task in which they had to identify the meaning of unknown words using only the surrounding linguistic context (Maguire et al., 2018). Children’s EEG was also recorded while alternating between having their eyes open and closed (resting state) for one minute each, for a total of 8 minutes.

Behavioral. To identify which factors predict variability in vocabulary size amongst low SES children we conducted a multiple regression analysis with vocabulary as the outcome variable and word learning, reading, working memory, gender, age, maternal education and language history as predictor variables. This analysis revealed a significant relationship between word learning and vocabulary (=.6, p<.02).

EEG. Our second goal was to identify if brain maturation, a factor previously identified as differing between children from low and high SES homes (Hackman & Farah, 2009), differs between strong and poor word learners within a low SES population. We conducted a median split on word learning accuracy to identify two groups: 15 poor learners and 15 good learners (group information in Table 1). Using time frequency analysis of the EEG, we investigated changes in the neural signal during resting state within the theta (3-7 Hz) and alpha (8-12 Hz) bands. We identified significant differences (ps<.05) between good and poor learners in both bands (Figure 1).

Discussion. These findings indicate word learning predicts vocabulary variability in children from low SES homes, even when accounting for other potential influences. Interestingly, while the good and poor word learners did not differ in their reading comprehension or working memory skills, they did exhibit significant differences in resting state EEG. Specifically, poor word learners showed neural patterns commonly only reported in children raised in extreme deprivation (Harmoney et al., 1990). Environmental factors, such as differences in stress or sleep, may impact brain maturation ultimately influencing word learning and vocabulary. Potential explanations for this variability will be discussed.

Authors

• Julie M. Schneider, University of Delaware
  Presenting Author

• Mandy J Maguire, University of Texas at Dallas
  Non-Presenting Author