The Neurocognitive Bases of Trust in Intellectual Disability

This project studies the neurocognitive basis of trust adjustment in intellectual disability (ID), a source of significant vulnerability for these patients, focusing on two target populations chosen for their specific social characteristics: people with Down syndrome, who are often described as being hypersocial, and people with Fragile X syndrome, who are often characterized by a completely opposite social behaviour profile, with a withdrawn attitude and significant social anxiety. The three different types of mechanisms that contribute to the adjustment of interpersonal trust: affective evaluation, trait attribution, and epistemic evaluation of informants, will be studied. Affective evaluation processes recruit subcortical structures such as the amygdala and assess potential social threats in the environment. The second mechanism for selecting whom to trust consists of forming a representation of a person's dispositions, such as benevolence and competence (also known as traits), and using it to predict that person's future behaviour. Trait attribution processes recruit a cortico-cerebellar network comprising the mPFC, CRUS I and posterior lobule VI. The third mechanism, called epistemic vigilance, allows to adjust our trust in what others communicate to us. This mechanism involves linking the assessment of the reliability of individuals who communicate (based on their benevolence and competence) with the reliability of the communicated information. Epistemic assessment involves frontal areas and areas associated with the representation of mental states in order to enable the evaluation of the truthfulness of the communicated information. All of these mechanisms become functional very early on, before a child's sixth birthday. There are reasons to expect that several of these central mechanisms supporting selective trust will behave atypically in intellectual disability.

NCT Number	NCT07434037
Lead Sponsor	Hospices Civils de Lyon
Conditions	Down Syndrome (Trisomy 21), Fragile X Syndrome (FXS)
Enrollment	112 participants
Start Date	2026-07-17
Primary Completion	2030-01 (estimated)
Study Completion	2030-01 (estimated)
Updated on ClinicalTrials.gov	2026-08-05