It’s really not experimental though.

Assuming their math and design are good, this is pretty strong, as these things go. But there were a lot of other things that were different between the groups that could reasonably be affecting results.

The article itself is careful to deny drawing any prescriptive conclusions from this research — a tacit acknowledgement that the causal connection isn’t entirely clear.

This is interesting and fairly strong, and potentially important, but definitely needs more work before we start acting on it.