People between the ages of 10 and 25 tend to be more aware of their surroundings than, for example, the average teacher or parent. Therefore, failure to respond to certain stimuli is often an early indication of zombification.

1          Failure to respond if their name is called (by a friend, not by a teacher making a roll call).
2          Failure to complain of acute and life threatening hunger at least two hours before official lunchtime.
3          Failure to look at someone of the opposite sex (or preferred alternative) and then, a) giggle with their friends, b) trip over, c) exaggeratedly ignore them, or d) walk into something/one by accident.
4          Failure to look at anyone at all.
5          Failure to check their telephone for mail, messages, or Facebook alerts at least every ten minutes.
6          Failure to a) laugh at, or b) be disgusted by, loud farts.
7          Failure to notice loud farts.
8          Failure to enthusiastically raise their hand when the teacher asks a question. Ha ha, just checking to see if you were paying attention. If someone whips their hand up when the teacher speaks they are probably not a zombie, because zombies are more likely to lurch, arms reaching out in front of them and making disgusting gurgling and groaning noises. Also more bitey.

All and any of these ‘failures’ (except 8) can be an indication of zombidom. However, it should also be remembered that a great many people of this age (extended teenage) routinely show signs of idiopathic dementia at least up until lunchtime, and may therefore fail to react normally to some or even all of the above mentioned stimuli (or indeed, any stimuli at all, up to and including the advent of a zombie apocalypse). This is a side effect of the shutting down of normal brain functions as a result of;

a) not enough sleep,
b) too much sleep,
c) extended periods of online gaming (see ‘a’),
d) depression,
e) elation,
f) low blood sugar levels,
g) low blood caffeine levels,
h) still being asleep,
i) high blood alcohol levels,
j) low blood alcohol levels,
k) misuse of various illegal and/or recreational psychoactive substances or frogs, and
l) being a teenager.

Because of this tendency to idiopathic dementia, you should avoid all life altering or threatening decisions, including decisions about zombidom based on the stimuli-reaction test outlined above, at least until lunchtime, or until your own morning dementia wears off and is replaced by the normal levels of hyper-reactivity and silliness.