Mathematical ability and musical ability may not seem on the suce to be connected, but people who have researched the subject—and studied the brain—say that riley are. Three quarters of the bright but speech-delayed children in the group I studied had a close relative who was an-engineer, mathematician or scientist and four fifths had a close relative who played a musical instrument. The children themselves usually took readily to math and other ytical subjects and to music. Black, white and Asian children in this group show the same patterns. However, it is clear that blacks have been greatly overrepresented in the development of American popular music and greatly underrepresented in such fields as mathematics, science and engineering. If the abilities required in ytical fields and in music are so closely related, how can there be this great discrepancy? One reason is that the development of mathematical and other such abilities requires years of formal schooling, while certain musical talents can be developed with little or no formal training, as has happened with a number of well-known black musicians. It is precisely in those kinds of music where one can acquire great skill without formal training that blacks have excelled popular music rather than classical music, piano rather than violin, blues rather than opera. This is readily understandable, given that most blacks, for most of American history, have not had either the money or the leisure for long years of formal study in music. Blacks have not merely held their own in American popular music. They have played a disproportionately large role in the development of jazz, both traditional and modern. A long string of names comes to mind—Louis Armstrong, Charlie Parker... and so on. None of this presupposes any special innate (先天的) ability of blacks in music. On the contrary, it is perfectly consisted with blacks having no more such inborn ability than anyone else, but being limited to being able to express such ability in narrower channels than others who have had the money, the time and the formal education to spread out over a wider ranger of music, as well as into mathematics, science and engineering. What is the main idea of the first paragraph?