Although I'm not sure I go along with the Multi-regional Theory of human evolution, I do think that Clive Finleyson's book "The Human's Who Went Extinct" touches on some very cogent points that often get overlooked or glossed over by those with their eyes on the Out of Africa Hypothesis. I certainly found them enlightening and have tried to incorporate them into my own way of thinking about the human species.
More than anything, while authors often give lip service to the fact that people are animals too, they often neglect what that actually entails especially for early humans. Many of the patterns of behavior among early people, regardless of their genus and species, were dictated by necessity and what was possible--even by sheer luck. These writers also seem to ignore the fact that most genera have more than one species in it and that those few that don't are usually under some degree of distress. I think this is something we should pay more attention to than we do when we look at our Neanderthal cousins as "failures," since it has ramifications for our own kind. In this context the author points out that this means that, far from one species "succeeding" another and winning the sweepstakes, there may have been many types of humans alive at any one time, each occupying their own little niche, much as other species in other genera do. That our co-genera species are no longer with us may have something important to tell us about our own contract with Mother Nature. One does not usually blame most extinct species for being "too dumb to live," as we are prone to do with our own ancient ancestors and their peers. All species are suited to the environment in which they evolved; it's only when nature changes the game plan that they may find themselves in trouble. The author makes this evident in his work on human species as well. I found that refreshing.
From the point of view of the archeologist, dealing with material remains from such a long time ago, the author notes that there isn't much by way of fossil evidence. He notes that many grand theories that massage the hubris of modern man's notion of himself have been built on next to no evidence. What there is of cultural material is biased toward what lasts in the record, stone and pottery--what there is of it. As he points out, this gives a much skewed perspective of what happened and who brought it about. His most interesting contribution is a discussion of just what technology is useful in what environment. Here he notes that it is probably the habitat in which any given human found himself that dictated the materials employed, what shapes were created and how the resulting tools were used; and not the intellect or the species of the individual user. He makes a number of references to modern, non-human animals who perform many of the feats of hunting and even trans-marine travel without nearly the mental ability of our distant ancestors and their contemporaries. I think this is very important. It is perhaps uncomfortable for us to believe that Neanderthal or Heidelberg men could become extinct, at least without our help, unless they were somehow mentally or physically defective. (This attitude brings to mind the old biases regarding races other than "our own.") To do otherwise puts us in the awkward position of having to admit that our success has as much to do with dumb luck as it does with our much vaunted "brain." It also makes it more evident that our luck could just "run out" one of these days just as it did for other species of human in the past. Here the author refers often to Jarod Diamond's Guns, Germs, and Steel: The Fates of Human Societies which makes similar points about the European contact with the inhabitants of the Americas.
I found the author's reference to the ranges of some modern animals, particularly the collared dove, very interesting and grounding. One tends to forget that the "great migrations" of our distant ancestors took place as they did and do with other animals and not as some grand manifest destiny. As population density increases, part of the group moves over a bit to have space and resources with which to raise their own "kids." Over generations, the range of the species expands until it hits some obstacle it can't go over or around. If major change occurs pockets of species may remain in refugia waiting for better times. If better times fail to come along, these populations may become extinct. With humans one tends to get the impression of a great "mission" or "destiny" with the expansion of ancient human populations that just isn't there anymore than it is for other animals. Even in more recent times, most people left their homes to find new ones so that they could promote their own interests. While a Genghis Khan might bring about a major migration for the purpose of conquest in the post agricultural world, in the pre-agricultural world this is most unlikely to have been a motivator. For one thing, "conquest" or "exploration," even "migration" would have to have been concepts that could even have arisen, and I'm not sure they could or did at the time. It's very unlikely that the ancestors of the Native Americans suddenly decided to mass migrate from Siberia to North America one day.
One of the issues that the author brings up with respect to which individuals survive hard times to populate the environment was particularly interesting and relevant. As he notes, it was those who lived marginal existences around a settled and conservative population that managed to navigate through whatever bottleneck occurred. This seems to have been the case with most plants and animals. He also suggests that the modern individual is essentially as "domesticated" as are the plants and animals upon which and with which he or she lives. The "wild form" of our own species is rapidly being crowded out of existence. While no human is less "modern" than another, some live closer to the "wild" existence than most of us do. In the event that a catastrophe occurs that brings about the collapse of society as we know it, it would be this "wild" population that would probably repeople the world--that is if we've allowed them to continue to exist--because they have the greatest experience with "making do" with almost nothing. I know I couldn't; I'm not sure I'd even want to. We might remember that destroying the dissenters of the world--like those living in the mountains of Afghanistan, the forests of South America and other marginal areas--may well put paid to the human experiment if and when Mother Nature decides she's had about enough.