、Table 2. Demographic characteristics of the piano, reading, and control groups Demographiccharacteristics Piano, n = 30 Reading, n = 28 Control, n = 16 Groupdifference, P Mean age, mo (SD) 54.7 (3.3) 54.6 (3.3) 56.6 (4.6) 0.174 Male/female 17/13 19/9 9/7 0.625 IQ (SD) 122.8 (10.9) 120.5 (12.4) 118.8 (9.9) 0.478 Digit span (SD) 12.1 (3.5) 11.3 (3.8) 12.0 (2.7) 0.664 Flanker (SD) 77.9 (18.7) 78.4 (19.9) 82.2 (19.8) 0.756Digit span scores are raw scores of the correct responses. The performance on the Flanker test is the percent correct responses. The P value for group difference in gender (male/female) was obtained using χ tests; the P values for other variables were obtained using one-way ANOVA. Flanker task) (44). The IQ test was based on five subtests, including vocab- ulary, similarities, animal house, picture completion, and block design. The piano group comprised 30 children (mean age = 4.6 y, SD = 0.28; one left- handed), the reading group comprised 28 children (mean age = 4.6 y, SD = 0.28; two left-handed), and the control group comprised 16 children (mean age = 4.7 y, SD = 0.38; one left-handed). The demographic characteristics of the groups are shown in Table 2.