The issue of music specificity of the observed associations deserves careful consideration. We made an effort to control a number of external variables that might have influenced the observed correlations. The socioeconomic factors of parents’ education and income, which are known to be associated with brain development (Hackmann & Farah, 2009), were statistically controlled for, as well as the age and gender of the children, and thus cannot explain the observed correlations. Furthermore, only a few children had hobbies or guided activities in addition to the playschool. Therefore,

it is highly unlikely that the associations found in the current study were related to the overall number of hobbies of the children. With regard to music-related external variables, it is important to note that as the children attended selleck screening library the same playschool and none of them had any additional formal musical activities they were matched DNA Damage inhibitor with respect to the musical activities outside the home. Also, all correlations remained significant when the duration of the playschool attendance and the number of hours spent listening to recorded music were controlled for. Importantly, neither of these factors correlated with the musical activities index or the response amplitudes. Finally, we found no evidence that the

responses of children whose parents were active musicians differed from the responses of children with non-musician parents. In sum, musical activities outside the home, the amount of exposure to recorded music, or the musical background of the parents cannot explain the associations between the musical activities at home and the P3a and LDN/RON amplitudes found in the current study. Participating in guided musical activities outside the home is quite typical for Finnish children and such activities

are offered widely in Finnish kindergartens. Therefore, our subjects do not dramatically differ from the Finnish norm in this regard. It could be nevertheless argued that the results might not be fully generalizable to children who have no musical activities outside the home. Children taking formal music lessons do indeed differ from children without musical training with regard to their perceptual abilities and various cognitive skills (Schellenberg, 2011), which might arguably influence how informal musical activities impact the why brain. Still, it should be noted that the musical activities in the playschool were of low intensity and concentrated on enjoyment of musical group activities rather than on specific music-educational goals and cannot be equated with individualized formal training on a musical instrument. Furthermore, the finding that the duration of the playschool attendance was not associated with any of the neurophysiological or questionnaire measures speaks against the suggestion that the associations between the response amplitudes and musical behaviours were modulated by the playschool activities.