I don't say they were stupid, but I think they were inevitably naïve in certain respects. Late-modern folks are likewise naïve--about the effects of consumerism on the planet, for example, or about whether theistic religion is compatible with science. I'm sure prehistoric people were capable of mapping patterns in the stars and seasons. They had to do so to survive. That doesn't mean they knew what stars or seasons are.
The question for me is whether prehistoric people would have faced alienation due to a recognition of life's absurdity, owing to knowledge of nature's inhumanity. The naivety in question is tied to animism, which in turn was a childlike cognitive strategy that preceded the accumulation of knowledge.
As I try to explain with respect to science, in other articles, mapping isn't the same as understanding (links below).
