The Out-of-Eurasia Theory
The reader should be convinced that OoA is just plain wrong. An alternative theory, Out-of-Eurasia (OoE) is proposed; Figure IV-1 gives the OoE tree. 1 Dotted lines indicate that the genetic contribution was minor; “Hn” is the Neanderthals, “He“ is Homo erectus, and “Aus” is Australopithecus. Lines are not proportional to time and dates are approximate. 2
If it were possible to draw a tree that showed man’s actual evolution proportional to the time that had passed, and the names of all known living and fossil primates were pasted onto that tree, almost all of the names of extinct species would be at the tips of small branches (i.e., dead ends), and the trunk and major branches of the tree would be bare (i.e., fossils that lie in the lineage of later species have not been found). Also, at any given time there would be several branches in existence, so that several species and races would co-exist, but usually not in the same location. Thus, the species named in Figure IV-1 are probably on branches that are not in our lineage, and are just examples of what the species in our lineage may have been like.
The OoE tree is very different from the OoA tree (Figure III-1). In the OoA tree, beginning with a primitive primate, which probably lived in Africa, there was an early expansion of erectus out of Africa, then man evolved from erectus into modern man entirely within Africa until 65,000 ya, when modern Africans left Africa, replaced non-modern Eurasian Homo species, and evolved into today’s Asians, who then evolved into today’s Europeans.
The OoE tree also begins with a primitive primate, 3 but in Asia, not Africa, and the African, Neanderthal, Caucasian, and Asian lineages split over 2 mya. 4 In OoA, the Africans evolved without any contact or help from any Eurasian hominoid, but in OoE Africans evolved very little on their own, and advanced primarily by receiving multiple infusions of Eurasian alleles as a result of interbreeding with more evolved Eurasian hominoids who migrated multiple times in to Africa. Thus, in OoE, there were (at least) four races of Australopithecus before man, Homo, evolved, and those races evolved into the races we see today. 5 Although OoA holds that Europeans evolved from Asian migrants into Europe about 46,000 ya, OoE holds that Europeans and Asians evolved separately all the way back to Australopithecus 6 over 2 mya, though with significant interbreeding. Also, in OoE there has been some interbreeding between Europeans and Neanderthals but, at least until recently, OoA held that there was no interbreeding.
Although OoA takes the egalitarian view that all the people alive today are modern (Hss), 7 under OoE, some s-S Africans and South Pacific aborigines are Hss-erectus hybrids, archaic Hs, or even late erectus.
Man is distinguished from all other animals by his disproportionately large brain and high intelligence. Any theory of human origins must explain which environmental factors selected for greater intelligence, from a primitive primate to modern man, at every major advance towards becoming a modern human. A theory of human origins must explain why greater intelligence was selected for at each step of the way, so that more intelligent individuals had greater reproductive success; one cannot simply assume that greater intelligence is always adaptive; it is not (Chapter 14, Intelligence as a Liability).
Every population asymptotically approaches a mixture of traits in which there is a balance of the amount of each trait so that every trait, including intelligence, is at its optimal amount in that mixture for that population, in that environment. If intelligence in man’s lineage constantly increased, as it did until recently, then the optimal amount 8 of intelligence must have constantly increased, which means that the payoff in reproductive success for having greater intelligence must have constantly increased, which means that the environment must have constantly become more mentally challenging.
As shown in Figure IV-2, the ancestors of man were subjected to a series of environmental changes, each of which resulted in a more mentally challenging environment that required more complex behavior; as a result, the optimal intelligence increased. Those individuals who were more intelligent were better able to engage in that complex behavior and obtain the resources needed for greater reproductive success, passing their alleles for greater intelligence on to the next generation. (Chapter 4, Rule 12). As the population neared equilibrium, where each trait was close to its optimum, selection pressure became less severe and the population stabilized until the environment changed again, either in the same location or because the population migrated to a new location. In that way, the optimal amount of intelligence kept increasing and selection pressures raised the intelligence of the population. And, once we had started down the path of increased intelligence, rather than some other path, no other animal, not even those who had just previously branched off from our lineage, could ever again surpass us in intelligence; that is why, when it comes to intelligence, we have no peers in the animal world.
What follows is an explanation of how our ancestors repeatedly found themselves in environments where those individuals who were more intelligent had greater reproductive success. The process occurred in two stages, the first in the sub-tropics, which took man to a bipedal ape, and the second farther north, which took man from a bipedal ape to Hss.
When the first mammals evolved from reptiles, the dinosaurs dominated the earth and most mammals were prey. Some hid in the day and foraged at night, a new environment that selected for better eyesight. More brain power was needed to process the additional visual information and those who had it, had more reproductive success. Some of these nocturnal mammals found safety underground, but others took to the trees. Of the tree climbers, some clawed the tree and other grasped branches. Of the graspers, those who had hands that better facilitated grasping had greater reproductive success as they could climb on thinner branches and reach and grasp food and carry it without using their mouth. By enabling the brain to more easily manipulate their environment, grasping hands raised the optimal amount of intelligence, and facile graspers had more reproductive success.
After the dinosaurs went extinct 65 mya, the ground became safer and some of our larger ancestors, who were less adept at moving through the trees, began spending more of their time on the ground. There they were more vulnerable to ground-dwelling predators, especially big cats. Those who had brains capable of communicating and cooperating were eaten less and had more reproductive success.
Next came habitual bipedalism and facile walking on the ground; it freed the hands, 9 which created another intelligence-enhancing feedback loop. One possible scenario (in accordance with behavior changing first, Chap. 4, Rule 12) is that the graspers carried things in one hand, struggling on two feet and the other hand, then more and more on just two feet. Those most adept at carrying had the advantage in reproductive success. Bipedalism meant that tools, weapons, and food did not have to be discarded when moving, but could be taken along. As a consequence, tools and weapons did not have to be made then discarded at each new location, so they could be made better, and making them better required a better brain and raised the optimal amount of intelligence. The feedback loop that bipedalism made possible, of larger brain → better technology → more food → larger brain again, continued until bipedalism became facile and the optimal amount of intelligence had been reached for warm, mostly non-seasonal, climates. When those territories had filled to carrying capacity, populations that lived in the northern fringes continued the same intelligence-enhancing feedback loop, but with the “technology” including heat conservation, e.g., control of fire, shelters, and body insulation, e.g., animal skins. 10
Now, still another intelligence-enhancing feedback cycle began. The optimal brain size and intelligence was not the same in every environment occupied by the bipedal apes. The major difference in optimums was between tropical climates that had a more-or-less single season, and sub-tropical climates that had four distinct seasons. Survival through the winter required hunting and hunting required more intelligence than gathering. 11 The greater the difference between summer and winter, the more mentally challenging the environment was, and the higher was the optimal amount of intelligence. 12 That is why IQ scores increase with distance from the equator and why the correlation between IQ and mean high winter temperature is -0.76. 13
Bipedal ape populations, like all populations, expanded to fill up all available territories to their carrying capacities. 14 The easily-exploitable southern territories were less mentally challenging and the optimal brain size (and intelligence) was therefore lower than in the more difficult and mentally challenging northern territories. Higher intelligence was selected for in the north because it enabled more of the individuals who had it to survive in the winter, giving them more reproductive success. As northern intelligence increased and body coverings were made, it kicked in the “larger brain → better technology → more food → larger brain” feedback cycle, where the additional food was the meat available in the winter. As they migrated farther north and the environment became increasingly more mentally challenging, the optimal intelligence needed to survive the cold and acquire food in the winter continued to increase. 15 Winter hunting also required better communicating, organizing, and cooperating, which also increased the payoff for more intelligence, raising its optimum.
If the reader will refer to Figure 14-2, he will see that the first large jump in brain size occurred 2 mya during the transition from Australopithecus to early Homo (Homo habilis and Homo erectus), when man became a facile biped and a proficient tool-maker during the “larger brain → better technology → more meat → larger brain” feedback cycle. (Holloway, 1981, pp. 291-292). The second large jump in brain size occurred at about 500,000 ya, when man increased his northern range by using fire (Table 17-2) and animal skins (>70,000 ya) to keep warm.
Eventually, the migrating populations reached the latitude where seasonal differences were at a maximum and, as they moved still farther north past that peak in seasonal differences, seasonal differences decreased again and, as they did, so did the mental challege of living there and the optimal intelligence, 16 though the optimum in the Arctic was still higher than the optimum in the tropics.
Northern populations, now superior to their southern ancestors in technology and cooperation, expanded back into the south, 17 conquering, displacing, and being absorbed into their southern ancestors. 18 The northerners who invaded the south had, of course, a higher than optimal intelligence for that less mentally challenging environment and, because the brain is costly and there was no longer a payoff in reproductive success for the additional intelligence, their intelligence began falling, though not necessarily all the way to the lower southern optimum. 19 Eventually, after all the populations had reached the approximate optimums for their environments, with the north higher than the south, the north-south differences in intelligence between contiguous territories 20 were no longer great enough to permit further conquest of the southerners by the northerners, and the process wound down. 21
Intelligence-enhancing processes ceased and even reversed somewhat when hunting-gathering gave way to agriculture in the Middle East about 12,000 ya. Although agriculture greatly increased the carrying capacity of the land, increasing numbers, it lowered populations’ optimal amount of intelligence, temporarily pitting smaller numbers of more intelligent hunter-gatherers against greater numbers of less intelligent farmers. When the dust settled, almost everyone was a smaller-brained and less intelligent farmer. 22
An intelligence-enhancing process began again on a smaller scale prior to the Industrial Revolution in Europe when the more intelligent and entrepreneurial individuals in the north were able to have and support more children. 23 That, and the Industrial Revolution that followed, brought the last great north-to-south migrations, to India, Africa, and the Americas. Today the northerners, thoroughly demoralized, no longer invade and conquer the south, but seek absolution for their sins by permitting and subsidizing the migration of southerners into northern territories. And average intelligence continues to fall. 24
It is difficult to make OoA consistent with these intelligence-enhancing processes because the processes would require much more time than 65,000 yrs. With today’s Africans having an average IQ of 67, and the Africans who migrated out of Africa 65,000 ya presumably having an even lower IQ, it is not reasonable to believe that supposedly modern Africans left Africa 65,000 ya and increased their IQ by more than 2 SDs in that short span, especially when selection for higher intelligence was not the strongest selector for most of those Africans most of the time. Moreover, by claiming Africa instead of Eurasia as man’s origin, OoA requires man’s defining attribute, high intelligence, to have a greater optimum in Africa than in Eurasia, which clearly contradicts today’s world-wide distribution of intelligence (as well as Rule 10 in Chap. 4). Thus, the evolution of modern man could not have occurred in Africa. 25
Bipedalism was needed for the south-to-north intelligence-enhancing process to begin, however, because it was not until bipedalism, when tools and weapons, the products of intelligence, could be preserved by carrying them, that a larger brain could pay for its high cost. On land, only bipedal apes have the anatomy, i.e., free hands with opposable thumbs, needed make use of high intelligence and reap its benefits. Thus, from bipedalism onward, man became more human in the north and the flow of his humanizing genes was from the north into the tropics not, as OoA supposes, the reverse.
Table of Contents
1. In 2000, Ronald A. Fonda made the case for the evolution of modern man in Eurasia on his web site. Also see (Fonda, 2001). Back
2. Dates during which a species lived are often inconsistent in the literature and, for some species, there is only a single fossil so the duration of the species can not be estimated. Back
3. e.g., Bahinia pondaungensis (Jaeger, 1999) in Asia. The LCA date may be about 57 mya. Back
4. “Instead, anatomically distinct races capable of interbreeding have evolved over at least the past 2 million years …” Alan G. Thorne of Australian National University in Canberra, reported by (Bower, B., “Pruning the Family Tree,” Science News, Vol. 148, No. 10, p. 154, Sept. 2, 1995). “We estimate the divergence time of H. sapiens from 16 genetic distances to be around 1.7 Ma [mya].” (Curnoe, 2003). Back
5. Carleton Coon (1962), also concludes that species came before race, i.e., that a pre-Homo sapiens species differentiated into races, and then those races evolved into races of Homo sapiens. Dates from genetic studies are more recent as they do not take interbreeding into account. Chromosome 22 gives an African-Eurasian LCA date of 634,000 ya (Zhao, 2000), while chromosome 1 results show an ancestral link at 757,000 to 805,000 ya. (Yu, 2001). The Neanderthal-Hss LCA is “estimated to be 465,000 years, with confidence limits of 317,000 and 741,000 years.” (Krings, 1999). The Asian-Caucasian LCA estimate is about 46,000 ya. (Mellars, 2006). When a new species forms it is unlikely to be a clean break with its parent species. Instead, the two species will interbreed on and off until they can no longer do so, either because of physical separation or genetic changes. Even after that, the parent species is likely to linger on for perhaps tens or hundreds of thousands of years before it is completely extinct. Back
6. See (Martinón-Torres, 2007) for dental evidence. Back
7. “Homo sapiens sapiens. All living humans are members of this subspecies.” (“The Long Foreground: Human Prehistory,” Washington State University, GenEd 110). Back
8. The optimal intelligence for a population is a bell-shaped curve having a mean, standard deviation, and possible a skew, all of which may change as the population’s environment changes. Back
9. In the next chapter, it is suggested that from prosimians on there were no quadrupeds in man’s lineage. Back
10. The first evidence of woven clothing is from about 27,000 ya in Europe (Soffer, 2000), though animal skins were no doubt used long before that. The human body louse evolved from the head louse about 72,000 ya ±42,000 yrs, when temperatures were low, suggesting that by that date humans not only lacked heavy body hair but, at least in cooler climates, had started wearing animal skins. (Kittler, 2003; Coon, 1962, p. 117). Back
11. "In warm-temperature, sub-tropical, and tropical latitudes, zero to thirty-nine degrees from the equator, gathering is by far the dominant mode of subsistence ..." More northern societies relied primarily on hunting and, more recently, fishing. (Lee, 1968, pp. 42-43). Back
12. “…seasonal variation in climate may also have been an important selective force behind the evolution of human cranial capacity." (Ash, 2007). In computer simulations, a varying environment speeds up evolution. (Kashtan, 2007). Back
13. IQ correlates 0.67 with distance from the equator, even within the continental U.S. (“Intelligence and Latitude in the US," The Audacious Epigone, Apr. 13, 2007). The argument could be made that the multiple droughts suffered by the Africans also made Africa a mentally challenging environment. The difference, however is that the seasons are highly predictable but the African droughts are not. Africans could store water, but it could be years before the next drought came and the energy put into maintaining the storage, and then successfully defending that resource during the drought, would probably be wasted. Back
14. (Templar, 2006). Man populated all the earth, but changing seasons gave him birth. Back
15. By analogy to one of “Murphy’s Laws” (stuff accumulates to fill the space available) all populations expand their numbers to fill the territory available to them. But territory is not available if it is already occupied by an equally fit population. Back
16. This south-to-north intelligence-enhancing cycle can also work in other directions, of course, provided the migration is into a more mentally challenging territory. For the Neanderthals, this happened when they moved west to east. Western Europe was warmed and moistened by the Atlantic Ocean, but Eastern Europe, far from a large body of water, was cold and dry and more mentally challenging. (Hoffecker, 2002-, pp. 3, 36, 249). Back
17. Note in Table 14-1 that although the Asian IQ averages 105, the Inuit (Eskimo) IQ average drops to only 91; however, the Eskimo visual memory is better than that of Caucasians. (Kleinfeld, 1971). Back
18. This process of going north, increasing in size and intelligence, returning south and interbreeding with the less advanced southerners, followed by selection of the hybrids, occurred repeatedly. (One can see an example of this with the success of the Chinese in Malaysia.) However, these migrations by northerners into the south were smaller and more localized than migrations into the south due to the two ice ages, and were probably more violent because they occurred over a shorter period. Back
19. Figure 21-1 suggests some of this north-to-south conquest. "Throughout history, most of the instances of people from one region attacking and conquering substantial portions of another region have involved 'northerners' invading more southerly lands." (Hart, 2007). “It is noteworthy that the expansion process was dominated by males, as is shown by a greater contribution to the Y-chromosome than the mtDNA from northern Hans [Chinese] to southern Hans.” (Wen, 2004). “… the male line of descent (as seen in the Y-chromosome) tends to derive from north of the homeland of the female line of descent (as seen in the mitochondrial DNA).” (Sailer, 2007b). The general pattern, repeated over and over again (Kemp, 2006), is that a more advanced population (MAP), usually from the north, conquers and dominates a less advanced population (LAP). Interbreeding occurs, weakening the more MAP and strengthening the LAP, which also picks up the culture, tools, weapons, etc. of the MAP. The LAP has numerical superiority and gradually absorbs the MAP, with or without violence and, many years later, the process starts all over again. Back
20. As discussed in Chapter 26, there are some reasons for believing that the intelligence of northerners who migrated into Africa declined. Interbreeding with previous migrants, who had a lower intelligence, would produce a hybrid population having an average intelligence in between that of the previous migrants and the new migrants. The optimal intelligence in the tropics was likely to increase after a northern invasion, however, because optimal intelligence depends upon culture, e.g., skills, as well as traits, e.g., grasping hands and good eyesight, and the optimum for the culture of the new migrants was likely to be higher. The optimal intelligence for chimps corresponds to their average cranial capacity 390 cc., but the optimal intelligence for Australopithecus, of about the same size and living in the same territory as chimps, corresponded to a cranial capacity 375 to 550 cc. Once Australopithecus had acquired the anatomy for facile walking, its behavior changed and its optimum, and actual, intelligence increased. (Chapter 4, Rule 10). Similarly, today in the tropics, with modern medicine, tools, and weapons, the optimal intelligence for man will be higher than it was only a few hundred years ago, though other African traits (e.g., impulsiveness) may limit its benefits. Back
21. Of course, if the northern and southern territories were not contiguous but were reachable by boat, the difference in optimums could be high enough to make conquest feasible. Back
22. The defenders of home territories have a large advantage, not only in knowledge of that territory, but in the will to defend it and, unless the attackers are significantly superior, the defenders usually win. “…the challenger is almost invariably defeated …” (Ardrey, 1966, p. 3). Back
23. “Although still rugged by modern standards, Mesolithic heads from Portugal and Brittany were diminished in size from those of their Paleolithic ancestors somewhat …” “… in this part of the Near East, skulls seem to have diminished a further stage in size and ruggedness from the Mesolithic peoples of Europe, essentially if not completely down to a sort of standard Mediterranean form of more recent times.” (Howells, 1959, p. 276-279). Back
24. The prosperous, i.e., the more intelligent, had many more surviving children than the poor in medieval and early modern England. (Clark, 2007). Back
25. Another intelligence-enhancing process occurred with the Jews. In Biblical times they were often the losers in tribal battles for territory, forcing them to migrate constantly, which selected for verbal skills. Later prohibitions against farming, but not commerce and finance, continued the selection for verbal and mathematical intelligence, as did other factors. See (“Jewish Genius,” by Charles Murray, Commentary, Apr., 2007). The Jews are not unique, however, and any population will increase its intelligence if selection for it is strong, though it may require thousands of years. Back
26. Note Figure 2-3 of Homo ergaster, who lived for a million years in Africa without improving his tools. Back