نص أصلي - انجليزي - The study, led by Dr. E. Glenn Schellenberg,...

The study, led by Dr. E. Glenn Schellenberg, examined the effect of extra-curricular activities on the intellectual and social development of six-year-old children. A group of 144 children were recruited through an ad in a local newspaper and assigned randomly to one of four activities: keyboard lessons, voice lessons, drama lessons, or no lessons. Two types of music lessons were offered in order to activities were provided for one year.