Intellectual disability (ID) is characterized by significant limitations in intellectual functioning (IQ below approximately 70) and adaptive behavior (conceptual, social, and practical skills) originating before age 18. Cognitive psychology contributes to understanding ID by analyzing the specific information-processing deficits that underlie intellectual limitations and by developing interventions that target these deficits.
Cognitive Characteristics
Individuals with ID show limitations in processing speed, working memory capacity, and executive function. Metamemory and strategic processing are particularly affected — people with ID are less likely to spontaneously use organizational and rehearsal strategies but can often benefit from strategy instruction. Attention and learning are slower but follow similar principles to typical development, supporting the view that ID represents a slower rate of cognitive development rather than a qualitatively different kind of cognition.
Different genetic causes of ID produce different cognitive profiles. Down syndrome is associated with relatively stronger visual-spatial processing and weaker verbal working memory. Williams syndrome shows the opposite: relatively preserved language and face processing with severe spatial deficits. Fragile X syndrome is associated with executive function deficits and anxiety. These specific profiles demonstrate that ID is not a monolithic condition but reflects diverse underlying cognitive architectures.