About our recent phylogeny and the contribution by "modern" humans (the main or only human ancestors of all humans alive today) to why the lineages of "archaic" humans stopped lengthening
The ÆPT concept "EAVASIVE" covers behavioral human symptoms of CURSES; mainly humankind's wide range of more or less sophisticated cognitive and language-function dependent (or closely associated) actentions.
Facial ticks, more or less complex Tourette type behavioral symptoms are typically also endogenously motivated by CURSES, as are clearly compulsive ideational ways of becoming preoccupied/behaving.
However, CURSES also co-motivate goal directed EAVASIVE behaviors or preoccupations (whether mundane or extraordinarily sophisticated in kind, and whether or not carried out successfully or with constructive or destructive consequences).
With this as a background, it is ÆPT to recognize what is likely to have significantly contributed to the end of archaic human lineages contemporary with our own "modern" human lineage was that our main "modern" ancestors were more potently EAVASIVE — yet not necessarily more technologically and culturally sophisticated.
That is, the EAVASIVEness of archaic humans may have come to differ enough from our "modern human" ancestors in that "the archaics" were significantly more prone to succumb to depression and less capable of being adaptively manic (less ambiadvantageously manic) than our main "modern" ancestors were.
In other words, the edge (in EAVASIVEness) our modern human ancestors had over our archaic human cousins manifested as an extra potent (not necessarily more elaborate) staunchness (ability to maintain steadfastness or unflinching fanaticism, of course coupled with a comensurately extra psychological resilience (resistance to becoming anxious and/or listless).
During the period of time when populations of archaic humans gradually shrunk and went extinct they clearly also frequently enough bred with modern humans who went on to become the common ancestors of most non-Africans alive today.
It is a fact that archaic humans contributed sufficiently adaptive traits so that some of their genetic recipe still remains as a small but not insignificant portion (roughly from about 1% to 7%) of the genomes of all non-African humans alive today.
It is likewise ÆPT to draw the conclusion that our our male "modern human" ancestors contributed to the demise of archaic humans [definitely Neanderthals and Denisovans but almost surely also other now likewise extinct subpopulations/lineages of humans] by raiding and usurping these their contemporary and closest evolutionary cousins.
Even though "romantic encounters" would surely have occurred between some archaic human males and some modern human females it is at least as likely (and ÆPT) to conclude that bride-stealing was not uncommonly associated with these raids on archaics.
Archeological evidence indicates that Neanderthals were no less intelligent (skilled or crafty) than their contemporary modern human cousins. Hence it is ÆPT to conclude that their eventual demise was not insignificantly violently contributed to by modern humans.
The ÆPT view is that the way the "moderns" and "archaics" differed genetically would have made the "archaics" both less inclined and less capable (than "moderns") of forming a fanatically focused and murderously motivated fighting force; whether the fighting fitness of the archaic humans were less adaptive in respect of naturally presented opportunities to usurp human neighbors (and obtain their "resources"), or less adaptive in respect of defending against being raided.
It is obvious that a phenotypic tendency of us humans (no less than of our closest living cousins, the common chimpanzees) to engage in violent inter-tribal competition existed back then and still exists, today.
In support of the ÆPT interpretation of our recent evolution, a known 'DNA-recipe ingredient' that mainly non-Africans have inherited from Neanderthals has been found to correlate with (cause and become expressed as) an increased risk of becoming depressed — i.e. of ending up in a state of listlessness, sadness or paralysing psychoemotional pain.
It is of ÆPT importance to note that this particular admixtured of archaic DNA does not predispose to a souped up "manic" state of mind (or a ditto EAVASIVE "actentiveness").
Another (or perhaps same?) admixtured 'archaic gene' has been found to predispose (or be involved in) addiction to nicotine, so it is likely that our archaic human cousins chewed some leafs or plants that relieved emotional pain and provided them with 'nicotinergic' (or some closely enough related psycnhoactive molecule that protected them against debilitating (mal-adaptive) depression.
"Modern humans" would not just have hasted the demise of "archaics" but when doing so they may very well also have cause the admixture of archaic genes into our lineage by bride-stealing.
The reason why archaic DNA is missing in current Y-chromosomes is not completely known, but it suggests that male archaics did not produce viable male offspring with female moderns and/or that bride-stealing from archaics only resulted in viable hybrid daughters. (Only future, or to me unknown already existing, findings by archeogeneticists can make me becoming even more 'ÆPTly sure' about this aspect of how we became admixtured with archaic DNA.)
Here is a recently published result of relevant research:
"Human TKTL1 implies greater neurogenesis in frontal neocortex of modern humans than Neanderthals"
The following passage applies to the evolution of archaic humans as well as of moderns:
Momentous mutations [i.e. selective sweep starting mutations] are have almost certainly been involved in how evolution (by neo-Darwinian natural selection) made us into the kind of fauna that we are.
And these momentous mutations played did of course always initially cause a clean (selective) sweep within their family and extended family group of origin.
The perceivable our overt manifestations of the traits given rise to by these (almost certainly pleiotropic) mutations would typically have been made a daunting, humbling and subservience prompting impression on mating rivals, and they would equally surely have made a positive and sexual attraction promoting impression on potential mating partners.
For example: Imagine the psychological effect on those family members siblings and close cousins who witnessed the first human (an ancestor to both archaics and moderns) who learned/figured out how to light a fire; or the impression made on those who witnessed the first human or human siblings who persistently insisted on mouthing a distinctly audible sound as a representation of what s/he was pointing to.
Same goes for the impression made by someone who made any kind of human music pioneering sound, or who pioneered the uniquely human capacity to painted pictures that reminded the artist's familiy group members of familiar animals.
Now back to the ÆPT view of we "moderns":
We are a species of animals that exists in sub-populations that to different degrees are capable of manifesting various more or less sophisticated examples of (what collectively is referred to as) The Arts and of making scientific and technological advances.
Aside from this difference, all normal (genetically so but also gestated, given birth to, and postnatally developed under sufficiently benign environmental conditions) humans are, given certain environmental (including social) preconditions and current circumstances, inclined to behave caringly and cooperatively.
However, it is ÆPT to recognize that we are also aptly characterized us as follows:
1. We are fiendish (more staunchly so than our extinct archaic cousins were) and inclined to behave so given sufficient environmental priming and triggers to behave viciously — including based on our tribal insitnct.
2. We are foolish — that is, even the most intelligent of us can be foolish. For example: the brain of generally intelligent people more often than not stop them from becoming devotees to the ÆPT dogma and from swallowing and digesting other concEPTs.
Aside from which, we are all extremely capable of and inclined to deceive ourselves and others by means of our verbal or otherwise symbolizing (language-related) cognitive functions.
[The sole proprietor of ÆIMC Internetional Ptd. Lty. is not one of the most intelligent of us, but he is not inEPT as far as his appreciation of all his own concEPTs.😏
Besides, and as if to make matters worse, people in general tend to deny themselves the pleasure of donating to ÆIMC Internetional. Because of this "ÆPT ideas marketed conspicuously" on the Internet have a less than a snowflakes chance to create a snow-storm of memes that would amend human affairs and help us to aim our societies toward becoming optimally regulated meritocratic market economies whose "optimal (socioeconomic) regulation"would have to be guided NOT by the principle "Do to others what you want done to yourself" but by the science-aligned instructive meaning of the thoroughly defined, subjectivity snubbing and seriously meant (although on its surface nicely mirth-inviting) ÆPT 'dogma' (or ditto motto/catch phrase) ALQ-holism is the best ism!" (or, conversely, ALQ-holists are the best ists!).
How some 'human-making' mutations resulted in selective sweeps depended on where and how they first played out:
At first, a selective sweep does of course take place within the extended family groups (local populations) wherein such a "momentous" mutations occurred.
Female individuals that pioneered (were the first to express) a pleiotropic mutation that resulted in an extra EAVASIVE phenotype (ditto characteristics) would typically have been more capable of attracting and choosing mating partners (and have more offspring) than their sexual rivals.
However, male pioneers of such "modern human making" momentous (likewise typically pleiotropic) EAVASIVE mutations would have played an even more significant role in these selective sweeps; Did so because of the much higher number of off-spring that male pioneers of such mutations were capable of producing.
Male mutants would have been able to do so by out-smarting, out-doing and out-impressing their sexual rivals — e.g. by manifesting pioneering talents that most importantly also impressed and attracted fecund females. (Female pioneers of extra EAVASIVEness would of course had a similar effect their mating rivals.)
For example, our EAVASIVEness-pioneering common ancestors would have had extra useful and impressive tool-making skills, plausibly (but of course not necessarily) 'pleiotropically paired' with a superior capacity and extra propensity to impress by making attempts to communicate verbally (even if at first no one could respond in kind). Some of these "pioneers of our EAVASIVE traits (or trait complexes)" would surely also have impressed in rudimentary ways of skills and talents that we now associate with all of "The (auditory and visual) Arts" — e.g. drumming/humming/singing, dancing, and sculpting/carving and painting.
The fate of less EAVASIVE ('less modern') family groups of hominine individuals tended to be sealed if they happened to be neighbors to a by a momentous EAVASIVE mutation as if souped up 'sept' [a "sept" = extended family group] that included our common ancestors.
In our relatively recent phylogeny mutations that conferred an 'EAVASIVE edge' become "fixed" (firmly established in our modern human lineage) by resulting in an intra-tribal selective sweep that involved all the various ways that mating rivals competed with each other.
Only after these selective sweeps had been completed did the added EAVASIVEness have repercussions by way of successive somewhat 'domino-effect-like' usurpings of distinctly less 'EAVASIVEly endowed' septs of neighboring humans.
Even though Neanderthals may conceivable have been more intelligent than their modern human contemporaries, they nonetheless would have been unable to withstand our male ancestors' and their likewise EAVASIVEly enhanced 'brothers in arms' because our mail ancestors and their cohorts possessed an extra EAVASIVEness that provided them with a superior capacity to maintain a fanatically focused, fearless, merciless and more methodically murderous attitude toward their less modern/less EAVASIVEly endowed human neighbors.
In humankind's African cradle (both beneficially and brusquely rocked by an indifferent "Mother Nature") every additional momentous EAVASIVE mutation would have tended to spread to eventually lead to that "modern humans" make up its entire human population.
Approximately since the ancestral pair that we have in common with today's chimpanzees, our phylogeny has involved 'pleitropic' mutations (some but not all of which have been EAVSIVEness-conferring but have at least resulted in selection pressures that tended to select for the preservation of mutations that conferred ambiadvantageously adaptive (eventually culminating in or as it happened leading up to EAVASIVE) traits — traits intimately involving verbal functions represented by the 3rd letter of EAVASIVE
These as if 'EAVASIVE preparing' mutations manifested as, for example:
1. A highly advantageous (adaptive) upright and well-balanced bipedalism, but this was 'paid for' by a concomitantly narrowed pelvis that made getting out from the womb into a guaranteed to be more or less traumatizing event — ÆPTly re-conceptualised as a SH imploring and CURSES incurring event that if to be survived also required to be SH-inducing (thanks to pain/distress-blocking functions that arouse early in the evolution of complex multicellular animals).
Some of these momentous mutations may well have been so pleiotropic (or pleiotropic in such a way) that they caused babies to be born both extra early and with bigger brains/craniums.
However, long previously evolved endoopiate-releasing neural mechanisms (and other relevant neural or neurohormonal functions would have kicked in (or came to the rescue).
I repeat: These inhibitory distress-blocking neural functions serve to prevent maladaptive distress by means of a release of endogenous opioids, and they have existed since early on in the evolution of complex neural animals.
2. The commensurately shortended gestation period caused a prolonged postnatal period of precarious self-helplessness (neoteny). This increased the likelihood that the immature offspring ended up under further SH imploring threats — e.g. predicaments or ordeals in which their psychosocial needs got seriously neglected and that automatically conditioned-in corresponding CURSES.
A CURSES is an automatically conditioned-in aftermath (or implicit memory) of a SHI threat.
CURSES have constituted an extra selection pressure that has prioritized the preservation of ambiadvantageous[ly adaptive] mutations — i.e. mutations that especially in the case of the evolution of modern humans have allow CURSES to co-motivate opportunity exploiting behavioral and mental preoccupations (focuses of actention).
3. A budding ability to with articulated sounds and with gestures (initially as something as simple as pointing with the index finger) communicate and coordinate goals and to co-operatively deal with perceived threats and opportunities.
Through further "modernizing" mutations today's variety of "EAVASIVE humans" arouse.