Dimensional Change Card Sorting of American Children: Marginalization-Related Diminished Returns of Age.

Background: While age is associated with an increase in cognitive flexibility and executive functioning as a result of normal development during childhood, less is known about the effect of racial variation in children's age-related cognitive development. The Marginalization-related Diminished Returns (MDRs) phenomenon suggests that, under racism, social stratification, segregation, and discrimination, individual-level economic and non-economic resources and assets show weaker effects on children's development for marginalized, racialized, and minoritized families.

Aim: We conducted this study to compare racial groups of children for age-related changes in their card sorting abilities.

Methods: This cross-sectional study included 10,414 9-10-year-old American children. Data came from the Adolescent Brain Cognitive Development (ABCD) study. The independent variable was age, a continuous variable measured in months. The dependent variable was dimensional change card sort (DCCS) score, which reflected cognitive flexibility, and was measured by the NIH Dimensional Change Card Sort. Ethnicity, sex, parental education, and marital status were the covariates.

Results: Older age was associated with higher DCCS score, reflecting a higher card-sorting ability and cognitive flexibility. However, age showed a weaker association with DCCS for Black than for White children. This was documented by a significantly negative interaction between race and age on children's DCCS scores.

Conclusion: Age shows a weaker correlation with the cognitive flexibility of Black than of White children. A similar pattern can be seen when comparing low-income with high-income children. Conceptualizing race as a social factor that alters normal childhood development is a finding that is in line with MDRs. Marginalization due to social stratification and racism interfere with the normal age-related cognitive development of American children.