With or without Feedback?-How the Presence of Feedback Affects Processing in Children with Developmental Language Disorder

Abstract

Language acquisition depends on the ability to process and learn probabilistic information, often through the integration of performance feedback. Children with developmental language disorder (DLD) have demonstrated weaknesses in both probabilistic learning and feedback processing, but the individual effects of each skill are poorly understood in this population. This study examined school-aged children with DLD (n = 29) and age- and gender-matched children with typical development (TD; n = 44) on a visual probabilistic classification learning task presented with and without feedback. In the feedback-based version of the task, children received performance feedback on a trial-by-trial basis during the training phase of the task. In the feedback-free version, children responded after seeing the correct choice marked with a green border and were not presented with feedback. Children with TD achieved higher accuracy than children with DLD following feedback-based training, while the two groups achieved similar levels of accuracy following feedback-free training. Analyses of event-related potentials (ERPs) provided insight into stimulus encoding processes. The feedback-free task was dominated by a frontal slow wave (FSW) and a late parietal component (LPC) which were not different between the two groups. The feedback-based task was dominated by a parietal slow wave (PSW) and an LPC, both of which were found to be larger in the TD than in the DLD group. In combination, results suggest that engagement with feedback boosts learning in children with TD, but not in children with DLD. When the need to process feedback is eliminated, children with DLD demonstrate behavioral and neurophysiological responses similar to their peers with TD.

Keywords: developmental language disorder; encoding; event-related potential; feedback processing; probabilistic classification learning.

Figure 1

(a) Illustration of the trial structure in the feedback-based training task; (b) Illustration of the trial structure in the feedback-free training task.

Figure 2

Overall test accuracy by task and group (* indicates p < 0.001).

Figure 3

Prototype learning by group and task. An examination of prototype learning between the two conditions (with and without feedback) for each group (TD, DLD) separately, revealed a significant difference between conditions in the DLD group (p = 0.025, indicated with a *) but not the TD group (p = 0.715).

Figure 4

(a) Grand-average frontal slow wave (FSW) recorded at FCz for feedback-free and feedback-based tasks in children in TD (shown in black) and DLD (shown in red). (b) Grand-average parietal slow wave (PSW) and late parietal component (LPC) recorded at Pz for feedback-free and feedback-based tasks in children in TD and DLD. (c) Topographic maps are generated for both tasks, covering the time window of 450–600 ms.

Figure 5

(a) Comparison of factor scores for frontal slow wave (FSW) at FCz between children with TD and DLD during the feedback-free task (shown in blue) and the feedback-based task (shown in green). (b) Comparison of factor scores for the parietal slow wave (PSW) at Pz between groups and tasks. (c) Comparison of factor scores for the late parietal component (LPC) at Pz between groups and tasks.