WHY IS IT, THAT 90%+ OF THE TIME, IT LEADS THE REST OF THE INDICES AROUND BY THE NOSE OR THE TAIL?

I'VE WATCHED IT FOR YEARS & HAVEN'T GOT IT FIGURED OUT ~ YET! LOL

(WHEN IT HITS A NEW LOW FOR THE DAY... THE REST WILL BACK-OFF & ATTEMPT THEIR OWN NEW LOW.  SAME WAY ON NEW HGHS FOR THE DAY.)  IT'S USUALLY IN THE ORDER OF: RUSSEL ~ DOW ~ S&P ~ NASDAQ