NEW YORK (AP) — When Stephen Dennis was raising his two sons in the 1980s, he never heard the phrase "screen time," nor did he worry much about the hours his kids spent with technology. When he bought an Apple II Plus computer, he considered it an investment in their future and encouraged them to use it as much as possible.Boy, have things changed with his grandkids and their phones and their Snapchat, Instagram and Twitter."It almost seems like an addiction," said Dennis, a retired homebuilder who lives in Bellevue, Washington. "In the old days you had a computer and you had a TV and you had a phone but none of them were linked to the outside world but the phone.