NEW YORK CITY — You may be familiar with the term "screenagers," which is a reference to teens who spend a lot of time on their phones. New research shows the roles may be reversing, however, as senior citizens spend more time on their phones. Adult children are now telling their parents to put the phones down. The number of older adults using smartphones soared from 55% in 2016 to 90% now, according to the AARP. That makes senior citizens one of the fastest-growing groups using digital devices.