While previous research on inhibition in people with Down syndrome (DS) reported
contradictory results, with no explicit theoretical model, on the other hand, a more homogeneous
impaired profile on the delay of gratification skills emerged. The main goal of the present
study was to investigate response inhibition, interference suppression, and delay of gratification in
51 individuals with DS matched for a measure of mental age (MA) with 71 typically developing
(TD) children. Moreover, we cross-sectionally explored the strengths and weaknesses of these components
in children and adolescents vs. adults with DS with the same MA. A battery of laboratory
tasks tapping on inhibitory sub-components and delay of gratification was administrated. Results
indicated that individuals with DS showed an overall worse performance compared to TD children
on response inhibition and delay of gratification, while no differences emerged between the two
samples on the interference suppression. Additionally, our results suggested that older individuals
with DS outperformed the younger ones both in response inhibition and in the delay of gratification,
whereas the interference suppression still remains impaired in adulthood. This study highlights the
importance of evaluating inhibitory sub-components considering both MA and chronological age in
order to promote more effective and evidence-based training for this population.
