Key points are not available for this paper at this time.
Even adults with no formal music lessons have implicit musical knowledge acquired through exposure to the music of their culture. Two of these abilities are knowledge of key membership (which notes belong in a key) and harmony (chord progressions). Studies to date suggest that perception of harmony emerges around 5-6 years of age. Using simple tasks, we found that formal music training influences key and harmony perception in 3- to 6-year-olds, and that even nonmusicians as young as 3 years have some knowledge of key membership and harmony.
Corrigall et al. (Wed,) studied this question.