When “we” began is a topic that’s the subject of a lot of research but (considering the mutual hostility toward biological science by all parts of the political spectrum) not much publicized. The first physically modern humans probably weren’t like us at all, except in outward appearance.
“Behaviorally modern humans” began about 80K year ago — this marks the first time that humanity is able to circumvent the blockade imposed on us by Neanderthals and Homo Erecti (Peking Men). Before circa 80K, the boundary of our species was determined by climate so, for example, Palestine was settled by Neanderthals, taken by physically modern men, and then retaken by Neanderthals — all basically a function of the temperature. 80K years ago, more or less, humans build boat, go along the coast of Asia (but apparently not entering — Peking Men probably ate us) and got to Australia.
“Culturally modern humans” seem to have started roughly 10K years ago, when inhabitants of the fertile crescent — who had not yet discovered farming — started living in cities. Consider that: for the first time, our species was living in high-density because we wanted to — because it was better to be with our fellows than be out in packs, even though we were still hunting animals and gathering plants. This doesn’t mean that behaviorally modern humans would not be capable or willing to live in cities, but the for the first time a metastable equilibrium toward city life existed.
In A Farewell to Alms, Greg Clark argues that what might be called economically modern man finally emerged 200 years ago, in England, after an extremely long period of intense malthusian selection. Clark’s politically smart enough to be coy about the mechanism, but it’s pretty clear he’s talking about genetic natural selection. (Malthusian selection really only operated in situations where starvation was a major cause of death. Among the Plains Indians, high rates of violence guaranteed there generally was enough food for everybody. So the Sioux were taller than some of the European settlers, because their more violent society was healthier for those who lived.)
Domestication is a continual process that produces dumber, weaker, and friendlier creatures. Our species is undergoing domestication — at different rates in different places and in different times.
This is why shrinking the Gap is more important than global warming: climate change is easier to deal with the later you put it off, because economic and technological growth compounds, making the solution easier every year. Shrinking the Gap probably gets harder every generation, as populations continue to diverge. Further, as populations are much larger nowadays (increasing the rate of natural selection), every generation of divergent evolution now is worse than a generation, say, ten-thousand years ago.