Control group
To know whether video games affect children’s behaviour, you need a baseline set of behaviours to compare to. The way to do this is to take some of the children from the sample (selected the same way as above) and exclude them from the experiment while keeping all other factors as equal as possible. This means you will expose them to the same environment during the experiment, and the same questioning or other behavioral tests afterwards; you will simply not give them the video games to play. In this way the control group and test group have been treated identically in all respects.
Why does a control group matter? Picture this extreme example. 10 kids play Modern Warfare 2 for 10 minutes then they all go out and shoot someone. So video games corrupted them right? What if you put 10 kids in a silent room for 10 minutes and they all go out and shoot someone too? That changes the picture completely – now it looks like video games didn’t have any impact on the children’s behaviour at all. A control group is therefore essential to be able to tell what is really going on, and without one, any test is worthless.
Sample size
This in my opinion is the single largest stumbling block of all the tests of video games corrupting children performed so far.
Some people seem to think that you can take a dozen kids and draw a meaningful conclusion from their behaviour. This is not true – in any subject matter – and although it seems fairly intuitive common sense anyway, I’m going to explain the scientific basis for why you need a much, much larger number of children to participate.
Let us take the example of a normal coin, and a weighted coin that will usually land on heads. We don’t know which coin is which, and we’d like to do an experiment to determine scientifically – which means beyond a reasonable doubt – which of the coins is biased.
You toss a normal (fair) coin ten times. On average, you expect it to land heads 5 times and tails 5 times. You then toss the weighted coin ten times. It lands heads 10 times. However, in this case, it so happens by random chance that the fair coin also lands heads 10 times. Which coin is which? You still don’t know. Why? Because you haven’t tossed them enough times to be sure.
We all know intuitively that it is perfectly possible to toss a fair coin 10 times and for it to land the same way up every time. It’s not very likely, but it does happen. This is because even though there is always a roughly 50/50 chance of it landing either way up, the heads and tails do not occur evenly. Over the course of many tosses, it will even out and we will see an approximately equal number of heads and tails. If we toss it many millions of times we may even discover that the result is 50.1% vs 49.9% because of imperfections in the coin or the way it has been tossed (and I will address both those issues later as they are important too). But the only way we can observe this is by repeating the coin toss over and over to minimise any influence by random streaks.
Analogizing this to children, 1 million coin tosses can be considered the same as tossing 1 million identical coins once each. One coin represents one child. Heads represents no change in behaviour after playing video games, and tails represents a significant, scientifically measured change. The difference between these two experiments is that it is unlikely the result will be 50-50, and we don’t yet know what the result really is, but otherwise the concept is essentially the same.
Why don’t we know what the result is? Simple: no test has ever been conducted on a large enough sample of children.