I was thinking the same thing. Our last common ancestor might have been something like [0] (the sister clade to Nephrozoa which is the latest common clade betwe

I was thinking the same thing. Our last common ancestor might have been something like [0] (the sister clade to Nephrozoa which is the latest common clade between us and octopuses). They just have sortof a nerve-net spread out over their body, nothing like a brain. The nerotransmitters affected existed before the split, but anything complex like social behavior affected by them seems like it must have been the result of convergent evolution. [0] https://en.wikipedia.org/wiki/Xenacoelomorpha https://en.wikipedia.org/wiki/Xenacoelomorpha