Isn't this really "Facebook is concerned that Instagram is toxic for teen girls" -- I don't think we can point to this conclusively and make any statement about

Isn't this really "Facebook is concerned that Instagram is toxic for teen girls" -- I don't think we can point to this conclusively and make any statement about "toxicity" because that's a subjective concept. But that Facebook is aware of it and is investigating further I think is all that is noteworthy here; it's not like they are accused of using this data and attempting to make Instagram more toxic for teen girls, which would be a much more shocking allegation. The idea that we (humans) can engineer engagement somehow is a misguided one; we stumble upon things and try to optimize things, but we don't have a theory of human behavior that will naturally give us concepts like this -- it's not even clear that such a thing could exist in any generality anyway, and if we had it, then it would naturally become ineffective because everyone would use it.