Humans have been evolving for greater intelligence for a very long time now, any free easy gains already been made.
I don't know. It may or may not be true, but it doesn't look obvious to me.
The issue is that "evolving for greater intelligence" competes with other things like "evolving for greater strength" or "evolving for greater alpha-ness" or maybe even simply "evolving to survive famines".
Because of TANSTAAFL greater intelligence comes at a cost (as a trivial example, the human brain consumes a LOT of energy) and the trade-offs the evolution makes are appropriate for the then-current environment. And our current environment is markedly different (there's your drastic change) from the one in which modern humans actually evolved.
It is quite possible that some trade-offs which held down the growth of intelligence are no longer operational and humans can/will continue to evolve towards even higher IQ.
Practically, of course, the point is moot as evolution is very very slow and humans will self-modify much more rapidly than evolution could provide any noticeable gains.
It is quite possible that some trade-offs which held down the growth of intelligence are no longer operational and humans can/will continue to evolve towards even higher IQ.
Maybe, but as you say, it would come at potential cost. E.g. gain of a few points but you won't survive famine, that doesn't sound very good.
Or much more insidiously, gains on an IQ test, at the expense of ability to form/organize/use complex background knowledge (IQ tests are designed to be minimally affected by extra background knowledge).
...Practically, of course, the point is moot
A long blog post explains why the author, a feminist, is not comfortable with the rationalist community despite thinking it is "super cool and interesting". It's directed specifically at Yvain, but it's probably general enough to be of some interest here.
http://apophemi.wordpress.com/2014/01/04/why-im-not-on-the-rationalist-masterlist/
I'm not sure if I can summarize this fairly but the main thrust seems to be that we are overly willing to entertain offensive/taboo/hurtful ideas and this drives off many types of people. Here's a quote:
The author perceives a link between LW type open discourse and danger to minority groups. I'm not sure whether that's true or not. Take race. Many LWers are willing to entertain ideas about the existence and possible importance of average group differences in psychological traits. So, maybe LWers are racists. But they're racists who continually obsess over optimizing their philanthropic contributions to African charities. So, maybe not racists in a dangerous way?
An overly rosy view, perhaps, and I don't want to deny the reality of the blogger's experience. Clearly, the person is intelligent and attracted to some aspects of LW discourse while turned off by other aspects.