Was looking for this response as it's the key point. If you're going to make a hypothesis that A leads to B then you should at other countries that also have A

Was looking for this response as it's the key point. If you're going to make a hypothesis that A leads to B then you should at other countries that also have A (in this case, lots of smart phones and internet) and see if they also have B (in this case loneliness). That doesn't seem to be the case, certainly not anywhere near the rate in the US. This basic practice refutes a really large percent of unfounded views, and so is really a good habit to get into when looking to explain things.