Quote from chaolin;807343:
Babies experience sensory overload and began to perceive what is true and what is not at a young age in order to to make sense of the world. Indirectly, I GUESS this suggests arithmetic is possible, but in my eyes it's much better proof of a fledgling sense of rational.
The reasoning goes like this:
By comparing the amount of time the baby spends looking at normal events to abnormal events, you get a ratio. You would expect the ratio to be 1, if they look at both equally (that is, for no reason). Any ratios significantly larger than 1, the subject has to understand something about what they're being shown, otherwise they wouldn't look for so long.
Now, why would the subject look for longer? (That is to ask, what is it that's wrong with the event that makes it abnormal?) Why, it's incorrect addition and subtraction, of course.
But there's a key word there, "incorrect". Naturally, there is one and only one way for a subject to be able to identify an incorrect addition event (something we have already established they can do) and that is for them to thoroughly understand a normal event to the point that they should be able to predict the outcome. Only when the outcome is different from their expectation do they respond, giving a ratio higher than one.
So, even though it's not a very exciting experiment, it's far more than indirect.