Aliens from planet Stirwet have landed on earth! Being hyper-intelligent and possessing superior technology, they immediately took over.
After having a quick look around, they found humans and apes (which they could not tell apart) to be the most interesting species.
(I don't mean they found us interesting to talk to, they just like looking at us and collecting us, as a fetish almost)
Before they began to collect the creatures they fancied and put them in jars of formalin for preservation, they used their superior technology to detect and classify all the human and ape creatures on the planet.
The classifier is an incredibly advanced piece of technology, which creates signals that can pass through the earth and this way find all the creatures on it, and classify them according to their Stirwet type.
Only the classifier kept glitching.
You see, the classifier should always return to the individual's base level. It can change for a short amount of time, because some property of the individual changes, but because the individual has a base level it should always return to that.
Here, an individual could be consistently classified as, for example, 2, but after an hour gets classified as 0, with equal stability. (Am I making this clear enough? I know it's hard to imagine a classifier not working properly).
So anyway, each individual was classified, almost always with 0 or 2, with small (as expected) quick glitches of 1, 3 and 4. Again, to clarify, no rules are broken if the classifier gives you a different score for a short amount of time, as long as you go back to your base classification. But is it 0 or 2? Why can't these creatures make up their minds?
To help the aliens take over and bring us to their world as decorations and toys, we need to figure out how we're messing with the classifier, and then stop doing it. But first we need to ask:
What does the classifier do?
Hints
The numbers are not arbitrary