Nearly 100 percent of high school students, 50 percent of junior high, and a third of those in grammar school now own cell phones. Even the word "cell phone" already sounds out of date, replaced even among foreign residents by "keitai," the shortened form of the Japanese word for portable phone.

According to a recent government poll, high school girls (again, nearly 100 percent of them) spend an average of two hours a day on their keitai, with high school boys clocking in at 90 minutes. An industry report last year showed that 127 million Japanese now own 100 million keitai.

That's a lot of button-pressing nationwide every single day. These changes may not signal any major shift in humanity, but for young people they do suggest disturbing trends. Two hours spent "chatting" by thumb is two hours not spent reading, playing sports or socializing face to face, activities that remain crucial to the mental, physical and emotional development of children. A full-fledged, full-time keitai generation has emerged in Japan, the implications of which are not yet entirely clear.