I think it is complicated because a lot of our long term fitness depends on the society. So, in the short term, you have some pressure for high promiscuity/low

I think it is complicated because a lot of our long term fitness depends on the society. So, in the short term, you have some pressure for high promiscuity/low intelligence, but over time you'd have a very fragile society, and the slower reproducing more intelligent society would be more successful in the long run either because it obliterated the less intelligent ones in war, or just because it was able to overcome things like natural disaster, child mortality, hunger, cold, heat and disease