They said the same about the internet but most kids just play games or go on Facebook :-)
I read a recent study by teachers using iPads in the classroom - they said that they didn't help learning as the children just played games or messed around with them instead.
Exactly. During traditional class, as I recall, your options are roughly these: 1) mess around with something, 2) study or make it look like that.
In terms of temporal motivation theory, the utility of messing around is much higher than the utility of boring study. Two ways to fix this—either lower the utility of messing around, or raise the utility of actual learning.
A punishment by teacher (with high enough expectancy) for messing around with classmates or cellphone does the first. Obviously, a book is too boring—but replace it with an iPad and children can now play games while no one notices[0], which makes the utility of messing around go up again.
Another, arguably better way would be raising the utility of actual learning relative to messing around with stuff. In other words, make so that children would like to do it themselves—through some psychological reward (valuable and close enough temporarily), or by making it an enjoyable process (i.e., immediate reward). It means fixing the system though.
[0] Like many of us, in regular day job environments, can (and do) procrastinate with the help of our fancy devices.
I read a recent study by teachers using iPads in the classroom - they said that they didn't help learning as the children just played games or messed around with them instead.