“Five Little Monkeys”

Jaden Lender, 3, sings along softly with the “Five Little Monkeys” app on the family iPad, and waggles his index finger along with the monkey doctor at the warning, “No more monkeys jumping on the bed!” He likes crushing the ants in “Ant Smasher,” and improving his swing in the golf app. But he is no app addict: when the one featuring Grover from Sesame Street does not work right, Jaden says, “Come on, iPad!’” — then wanders happily off to play with his train set. The study, by Common Sense Media, a San Francisco nonprofit group, is the first of its kind since apps became widespread, and the first to look at screen time from birth. It found that almost half the families with incomes above $75,000 had downloaded apps specifically for their young children, compared with one in eight of the families earning less than $30,000.

Now a more mature 14 months, Alex’s attention span for apps has grown. “If we’re stuck on the subway, he’ll play with them for three, maybe five, minutes,” Mr. Wingard said.

He and his wife still don’t use them much, he said: “We’re scared he’ll break the phone.”

AA