I&#x27;ve been interested in brain training and nootropics for a very long time. The conclusion I&#x27;ve come to is intelligence is pretty much fixed, current psychopharmaceuticals are of very, very, very limited usefulness, and most of the differences in intelligence we see between people are caused by genetic factors not education or rearing. This was immensely disappointing for me - I&#x27;d literally give everything I own to be moved up a few standard deviations, but it does seem to be the case. I&#x27;ll be the first in line for any effective enhancement, but we do not have them now. The most likely approaches for increasing the intelligence of humans are things like embryo selection and genetic engineering of embryos - biotechnology can only do so much after your brain is done growing.<p>Iterated embryo selection looks like it will lead to humans smarter than any human who has ever lived - perhaps they will be clever enough to figure out how to upgrade an old fogey like me. As an aside, I&#x27;m not sure people understand how ridiculously cheap iterated embryo selection will be provided some very conservative advances in biotech, ethical mores will be unlikely to suppress it - even if international treaties are put in place.