Is that a pibu or a pibo? Children with reading and language deficits show difficulties in learning and overnight consolidation of phonologically similar pseudowords

Abstract

Word learning is critical for the development of reading and language comprehension skills. Although previous studies have indicated that word learning is compromised in children with reading disability (RD) or developmental language disorder (DLD), it is less clear how word learning difficulties manifest in children with comorbid RD and DLD. Furthermore, it is unclear whether word learning deficits in RD or DLD include difficulties with offline consolidation of newly learned words. In the current study, we employed an artificial lexicon learning paradigm with an overnight design to investigate how typically developing (TD) children (N = 25), children with only RD (N = 93), and children with both RD and DLD (N = 34) learned and remembered a set of phonologically similar pseudowords. Results showed that compared to TD children, children with RD exhibited: (i) slower growth in discrimination accuracy for cohort item pairs sharing an onset (e.g. pibu-pibo), but not for rhyming item pairs (e.g. pibu-dibu); and (ii) lower discrimination accuracy for both cohort and rhyme item pairs on Day 2, even when accounting for differences in Day 1 learning. Moreover, children with comorbid RD and DLD showed learning and retention deficits that extended to unrelated item pairs that were phonologically dissimilar (e.g. pibu-tupa), suggestive of broader impairments compared to children with only RD. These findings provide insights into the specific learning deficits underlying RD and DLD and motivate future research concerning how children use phonological similarity to guide the organization of new word knowledge.

Keywords: artificial lexicon; consolidation; developmental language disorder; phonological competition; reading disability; word learning.

Figure 1

A sample trial from the artificial lexicon learning experiment

Figure 2

Accuracy across blocks for the artificial lexicon learning experiment. The first six blocks constitute the first day of learning, whereas the last two blocks (i.e. to the right of the dashed line) constitute the second day. Points and standard error bars represent raw data, whereas solid lines represent model fits

Figure 3

Accuracy across blocks for the artificial lexicon learning experiment for the RD + DLD group alongside the subgroup of 34 children from the RD‐only group who were reading skill and age‐matched to the RD + DLD group. The first six blocks constitute the first day of learning, whereas the last two blocks (i.e. to the right of the dashed line) constitute the second day. Points and standard error bars represent raw data, whereas solid lines represent model fits

Figure 4

Adjusted Day 2 Block 1 accuracy (residualized on Day 1 learning estimates as well as the amount of time elapsed between Day 1 and Day 2 testing sessions) for the three learner groups and three stimulus types. Note that because accuracy values are residualized, they can be negative. Individual data points are jittered within the violin plots. The white triangles indicate group means for each stimulus type

Figure 5

Adjusted Day 2 Block 1 accuracy (residualized on Day 1 learning estimates as well as the amount of time elapsed between Day 1 and Day 2 testing sessions) for the RD + DLD group alongside the subgroup of 34 children from the RD‐only group who were reading skill and age‐matched to the RD + DLD group. Note that because accuracy values are residualized, they can be negative. Individual data points are jittered within the violin plots. The white triangles indicate group means for each stimulus type