The Gradual Development of Lateral Inhibition During Word Recognition in School-Age Children

Word recognition is supported by a competition process in which words that partially match the input are activated and vie for recognition. Recent work has shown that adolescents with Developmental Language Disorder (DLD) do not fully resolve this competition, likely due to a deficiency in inhibition among words (lateral inhibition). It is not yet clear how this develops. Three experiments investigated the development of lateral inhibition using a variant of the Visual World Paradigm. Experiment 1 compared adults (N=35), older children (11-12) (N=43), and younger children (7-9) (N=45). In line with previous works, adults demonstrated robust inhibition, with marginal evidence in older children and no evidence in the youngest children. Experiment 2 tested 222 younger children to achieve greater statistical sensitivity and found a small but significant effect. Experiment 3 asked if these weaker effects were due to the younger listeners’ failure to activate competitors, or if competitors were active but simply not inhibiting the target. It found robust competitor activation even in younger children, suggesting the weaker effects may derive from true inhibition differences. Implications for DLD are discussed.