Not really. Paleolithic HGs (like most hunter gatherers on earth) where as strong as the strength and intelligence of all the group. The HG group takes care of all the members and care of all their kids, like one big family. They hunted and gathered together sharing spoils equally regardless who was smarter, or a better hunter or not, and regardless who had more kids or none. In this situation there is no strong evolutionary forcing to reward intelligence of individual. These condition resemble our modern western society, more than farmers, kingdoms and feudalism did.
I think the final kick of intelligence, which started civilizations (including Greek and Rome) came from farmer's societies. Farmers are more individualistic and possessive. They have their own land, they work only for their immediate family, and never share everything with the whole village in equal sense of HGs societies. Accumulation of wealth by individual farmer is highly beneficial to his offspring. The more intelligent and more hard working the farmer is the better chance of survival of his children and propagation of farmer genetic traits. Conversely the poorest and not that smart in the farming village always died early and without offsprings. This creates a strong evolutionary trend towards intelligence.
This was a cruel and unjust world they lived in, and I'm not really fun of it, but it is possible that it strongly influenced our intelligence and hard repetitive working.
Mind you that there is no civilization started by hunter gatherers, but their are few started by farmers, and independently on all continents.