It's actually the mainstream position in archaeology that humans had some kind of cognitive development happen to us about 40,000 years ago.

That is absolutely not the mainstream position unless you have been asleep for the last decade or two.

This idea of "behavioral modernity" has been pretty thoroughly demolished. In the past 20 years, an increasing number of papers have appeared which show that the stuff people point to as appearing at 40,000 years actually appeared tens of thousands of years earlier. Blade and microlith technology, bone tools, specialized hunting, long distance trade, art and decoration. All of these things go back 100,000 years in the archaeological record, and probably a lot more as we push back the dates with new discoveries.

McBrearty and Brooks wrote the definitive paper that demolishes "behavioral modernity" in their 100+ page methodical and painstaking review of all of these lines of evidence, taking them apart.

See:

• McBrearty, S., & Brooks, A. S. (2000). The revolution that wasn’t: a new interpretation of the origin of modern human behavior. Journal of Human Evolution, 39(5), 453–563.

If you want something shorter, try this:

• Shea, J. J. (2011). Homo sapiens Is as Homo sapiens Was. Current Anthropology, 52(1), 1–35.

They don't mince words:

Paleolithic archaeologists conceptualize the uniqueness of Homo sapiens in terms of “behavioral modernity,” a quality often conflated with behavioral variability. The former is qualitative, essentialist, and a historical artifact of the European origins of Paleolithic research. The latter is a quantitative, statistically variable property of all human behavior, not just that of Ice Age Europeans. As an analytical construct, behavioral modernity is deeply flawed at all epistemological levels. This paper outlines the shortcomings of behavioral modernity and instead proposes a research agenda focused on the strategic sources of human behavioral variability. Using data from later Middle Pleistocene archaeological sites in East Africa, this paper tests and falsifies the core assumption of the behavioral- modernity concept—the belief that there were significant differences in behavioral variability between the oldest H. sapiens and populations younger than 50 kya. It concludes that behavioral modernity and allied concepts have no further value to human origins research.