In their perspective field ?

Hi~ I have no idea about the meanig of "perspective" in this context.

What could be the best interpretation of that?

Thanks for your help~!

He conducted a 5-year study of geniuses in six fields: concert pianists, sculptors, tennis stars, Olympic swimmers, research mathematicians, and research neurologists. He made a direct link between their advanced achievements and the hours spent on gaining automation of key related knowledge (Bloom, 1985). The study noted that all the
geniuses practiced an average of 25 to 50 hours a week for 12 to 16 years to obtain the pinnacle in their perspective fields. The conclusion reached was that only at a level of automaticity can the brain make
profound connections.