In the WM measures, results showed a main effect of age for both
Rspan and Matrices: 10-year-old children performed less well than the
other two age groups (10- vs 11-year-olds, p b 0.01 and p b 0.05, respectively;
10- vs 12-year-olds, p b 0.001 and p b 0.01, respectively), while
the 11- and 12-year-olds did not differ significantly from one another.