According to the age differentiation hypothesis, cognitive abilities become more differentiated with increasing age during childhood. Using data from the German standardization of the SON-R 2½–7 intelligence test, we examined age-related differentiation of cognitive abilities from age 2½ to age 7. The SON-R 2½–7 is a nonverbal intelligence test for children and consists of six subtests. SON-R 2½–7 supposedly has a two-factorial structure, with a reasoning and a performance factor. We used age-weighted measurement models to describe the age gradients of model parameter estimates. In line with the differentiation hypothesis, we observed a decrease in the correlation between both factors with increasing age. We tested the significance of this observed decrease using a permutation test. Participants were allocated age randomly in 1,000 datasets. Age-weighted measurement models were estimated to observe the age gradients of the correlation between the two factors in these datasets. The results of the permutation test show that the decrease in the correlation observed in the real dataset is significant but of small magnitude. The findings provide some support for intelligence differentiation with increasing childhood age.