[SauronOfMordor]

Without getting into esoterica, I think there is a substantial amount of evidence that our brains are capable of not insignificant intelligence enhancement without chemicals (e.g. through environmental stimulation), but are largely limited by plasticity and generation of the computing substrate. At the same time, it would be difficult to coax too much additional capability out of our existing hardware; you can only drive so many synapses off a neuron, and location matters.

It's long been determined that lack of stimulation and neglect in infancy/childhood can produce a mentally-deficient individual. I think there may be things we can yet do in developing children that can more closely approach the genetic limits of their potential intelligence. There is a lot still to do in the area of discovering games and activities that may improve the intellectual development of children

[tortoise]

It's long been determined that lack of stimulation and neglect in infancy/childhood can produce a mentally-deficient individual. I think there may be things we can yet do in developing children that can more closely approach the genetic limits of their potential intelligence.

This is a good point. There is no reason we couldn't maximize the intelligence of people who aren't operating at their full potential, and there probably is some therapy that could help with this. It isn't like there is an over-abundance of super-intelligent people in the world. :-)