Working memory, inhibitory control, and reading disability

This study investigates the relationship between working memory, inhibitory control, and reading disability across the lifespan. Specifically, it seeks to determine whether deficits in working memory—a core component of reading and learning—are caused by limited cognitive capacity or by failures in inhibitory control mechanisms (access, deletion, and restraint).

The researchers analyzed data from 966 individuals aged 6 to 49, comparing skilled readers with those having reading disabilities. Participants completed a listening span task in two formats: a standard blocked format (which is susceptible to proactive interference) and a mixed format (designed to minimize such interference). The researchers examined error patterns—specifically intrusion errors—to assess how effectively participants could prevent irrelevant information from entering or remaining in their working memory.

• Reading Disability: Individuals with reading disabilities consistently demonstrated lower working memory spans than skilled readers across all age groups. This deficit is linked to difficulties in the access and restraint functions of inhibition, meaning these readers struggle to filter out irrelevant information.
• Aging: While working memory performance in the standard blocked format declined after age 20, this decline disappeared when using the mixed format. This suggests that age-related "declines" in working memory are not due to a loss of raw capacity, but rather to increased susceptibility to proactive interference caused by less efficient inhibitory control.
• Inhibitory Functions: The study provides evidence that the access function of inhibition improves through adolescence but becomes less efficient in adulthood, contributing to the performance patterns observed in older participants.

These findings challenge the traditional view that cognitive decline with age is solely a result of reduced mental capacity. By demonstrating that procedural changes can mitigate age-related performance drops, the study highlights the critical role of inhibitory control in cognitive processing. Furthermore, it clarifies that reading disabilities involve a persistent, lifelong struggle with managing irrelevant information, which distinguishes these individuals from those experiencing typical age-related cognitive changes.