MUSIC AND IQ: CONTROVERSY AND EVIDENCE WEAK JUSTIFICATION FOR COMBINING GROUPS A Reply to Schellenberg (2005)

Schellenberg (2004) assigned 144 6-year-old children to one of four treatments in a pretest-posttest design. Subjects experienced either keyboard, Kodaly voice, drama, or no lessons over an academic year. Schellenberg reported a significant difference of 2.7 IQ points if the keyboard and voice results were combined and contrasted against the combined drama and no-lessons results. Steele (2005) and Black (2005) questioned the justification for this combination and reported that the general pattern was weak and nonsignificant differences in the absence of this particular combination. Schellenberg (2005) attempted to justify this combination by appeals to the expense of the project and pubhe interest in the research question. The result is explained as being due to the school-like nature of the activities. This explanation raises the question of why drama lessons are not school-like and instead were combined with the no-lessons group.