Socio-economic deprivation at age 3 affects language and Theory of Mind development

Children from disadvantaged socio-economic backgrounds have lower average vocabulary and problem solving abilities at age 3. This study investigates whether children from disadvantaged socio-economic backgrounds also show lower metacognitive and metalinguistic skills. Language and Theory of Mind are strongly related and family background has been shown to contribute to False Belief understanding. Participants were 77 children (mean age 43 months) from quintile 1-4 of the SIMD (Scottish Index of Multiple Deprivation). Children were tested on general language abilities, problem solving, executive functioning, Theory of Mind, and metalinguistic tasks assessing word learning and flexibility in using familiar words. Ranking on the SIMD correlated to general language abilities and Theory of Mind, even when controlling for age. Children from the most deprived background had significantly lower expressive vocabulary and problem solving scores than in the least deprived group of this sample. The ability to use familiar words interchangeably (dog – animal) was also significantly lower. No differences were found for executive functioning or word learning
tasks. A subsample matched on verbal ability and chronological age (n 1,2 = 20) differed significantly only on ability to predict False Belief, but not on any other cognitive or linguistic task. We suggest a specific delay in Theory of Mind development in children from deprived areas, which cannot be explained by maturity or verbal IQ. Ongoing effects of these delays on word learning are currently being investigated longitudinally.