your brain turns the right side off. the side which is used to think analiticly, and the left side fully activates to produce the alph waves
Actually, that would be the left hemisphere.
You're right about going into a trance-like state, though. While watching television, you are very suseptible to advertising. You burn more calories sleeping!
It's possible some of these people are defficient in certain vitamins and/or minerals.
if they arent bothering to revise why would the exams bother them?
Mabye the guilt of not studying and worrying about their marks is bothering them.