About a quarter of Japanese high schoolers say they are dependent on the internet.

A new study by Tokyo University surveyed about 15,000 Tokyo high school students.

Students average about two hours and forty minutes surfing the net on their smartphones each day.

Girls tend to spend about an hour longer than boys.

Almost ten percent admitted to being late or missing classes because they were on the web.

Computers accounted for only about 40 minutes a day of net usage and tablets just 14 minutes.

The author of the study says while Japanese girls spend longer on the net than boys, they tend to be more aware of possible bad effects.