The Relative Strengths of Relationships Between Fine Motor Skills, Working Memory, Processing Speed and Fluid Intelligence in Early Elementary School Children

The goal in the present paper was to examine the combined and relative impact of fine motor ability, auditory working memory, and processing speed on fluid intelligence in a sample of early elementary school students. Our participant sample was 145 children (Mage = 9.1 years, SD = 1.1; 80 boys, 65 girls). We used the Raven's Colored Progressive Matrices Test as a measure of fluid intelligence and five other measures to represent the three predictor variables: the Grooved Pegboard Test as a measure of fine motor skills, Digit Span Forwards and Digit Span Backwards tests as measures of working memory, and Rapid Automatized Naming and Letter-Digit Substitution tasks as measures of processing speed. Regression analyses indicated that only two of these measures had a statistically significant association with the fluid intelligence test scores, namely, scores on the Grooved Pegboard (fine motor skills) and Digit Span Backwards (working memory) tests, with these two measures explaining 35% of the variance in the fluid intelligence test scores. Thus, fine motor skills and working memory were correlated with fluid intelligence in early elementary-grade students. Until the directions of these relationships are better understood, we might assume that interventions aiming to increase young children's fluid intelligence, or at least their intelligence scores, might partly target working memory and fine motor skills.