I’ve just had en exam where we were presented with two variables. In a dictator game where a dictator is given 100 USD, and can choose how much to send or keep for himself, there was a positive correlation between age and how much money the participants decided to keep.
My thinking is that you can’t infer causality from this because you can’t infer causation from correlation. My classmate thinks that you can because if you, for example, split the participants up into three separate groups, you can see how they differ in how much they keep and how much they share, and therefore conclude that age causes them to keep more. Who is correct and why?
In general you should not assume that correlation implies causality – even in cases where it seems that is the only possible reason.
Consider that there are other things that correlate with age – generational aspects of culture for example. Perhaps these three groups will remain the same even as they all age, but the next generation will buck the trend?
All that being said, you are probably right that younger people are more likely to keep a larger amount, but just be aware there are other possibilities.