Some salient details of how our EAVASIVEness evolved
Momentous pleiotropic mutations [i.e. selective sweep starting mutations] that added to or tweaked at the time already existing cortical cognition-underpinning functures of our ancestral geno/phenotype have almost certainly been involved in how evolution (by neo-Darwinian natural selection) made us into the kind of fauna that we folk now are.
All these momentous mutations played out their role by at first becoming fixed in context of their extended family group of origin. [In more ÆPTly chosen words: These important mutations were strongly selected for in their sept of origin.]
We are a species of animals that exist in sub-populations that vary greatly in respect of their output of visual and auditory Arts and products of Science (including technological advances).
Aside from these stark differences all humans are, if given certain environmental (including social) preconditions and current circumstances, on the whole inclined to behave caringly and cooperatively as well as 'far less nicely'.
I is ÆPT to recognize that it is apt to not just characterize us self-flatteringly but also as follows:
1. We are fiendish — e.g. we are clearly inclined to become triggered to behave viciously based on our tribal insitnct;
2. We are foolish — i.e. even the most intelligent of us can be foolish (e.g the brain of generally intelligent people more often than not stop them from becoming devotees to the ÆPT dogma and from swallowing and digesting also 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.
How EAVASIVE-making mutations proved themselves adaptive:
At first, such a momentous (selective sweep causing) mutation does of course play out within the extended family group (local population) wherein it occurred.
Female individuals that pioneered (were the first to express) such a pleiotropic mutation (that resulted in an extra EAVASIVE phenotype or 'ditto characteristics') would typically have been more capable of attracting and choosing mating partners (and have more offspring) than their sexual rivals.
Male pioneers of such momentous (and likewise typically pleiotropic) EAVASIVE mutations would have played an even more significant role in these selective sweeps simply because of the much higher number of off-spring they were able to produce by procreating with more than one of the females in their extended family group.
Male such mutants would have been able to do so by outsmarting, 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 have done the same in relation to their mating rivals.
Our 'EAVASIVEness pioneering' common ancestors would typically have some extra useful and impressive skill or skills.
That is, a momentous "ambiadvantageous" ('EAVASIVE') mutation, one that a common ancestor of ours were the first to carry and express, would typically have been 'pleiotropic' in character, and so, it could plausibly (but of course not necessarily) have resulted in not just an unprecedented talent for (e.g.) tool-making but it may also have resulted in one or more other talents and adaptive skills.
Accordingly, it is conceivable (ÆPTly so) that an ambiadvantageous mutation also conferred (i.e. did amongst else) a new and superior capacity (as well as an extra propensity) to impress both potential mating partner and mating rivals by audibly manifesting a brand new ability to communicate verbally — doing so even though no other family group member at this ability (hence could respond in kind).
The ÆPTly conceived or recognized character of EAVASIVEness-adding ambiadvantageous mutations do not merely hold that such momentous mutations in a our relatively recent phylogeny conferred an unprecedented adaptive ability to be practically and mentally preoccupied in some new ways which exploited one or more environmentally present opportunity. [In other words, such mutations resulted not just in traits that were opportunity exploiting — as dialectically opposed to "threat managing".]
A recognition of what they also resulted contributes to an near enough complete general definition of an ÆPT evolutionary principle that explains ourselves in an AFAIK unprecedented way. This principle can also be though of as a sub-heuristic to Darwin's "Natural Selection".
This other aspect of what such mutations conferred was a not so much of a reinforcement of a preexisting capacity (in existence since far back in the phylogeny of all animals) to remain adaptively inactentive in face of insignificant situational sources of stimulation but much more (and more specifically) a reinforcement of a no less early in our phylogeny emerged capacity to remain adaptively inactentive in face of neural messages that represent threats that in most lifetime circumstances would "be paid maladaptive actention" unless synaptically blocked and thus prevented from being synaptically relayed (i.e. relayed as if by default) to motivate a distress-type actention.
The only two points that need to be added about this ÆPT heuristic is the threats involved are circumstantial threats of SHI-type and survived such threats that became conditioned-in (hence left behind inside brains as a primarily insidious or 'threat-type' aftermath) as CURSES kept unconscious (unactended to) by means of SH.
Apropos which, it is ÆPT to mainly associate any realistic "actention" (whether a distress-type or pleasure-type such) with a response/preoccupation/behavior that correlates with an acutely activated neural "actention module" that thus can be seen (or APTly so) to have temporarily as if 'won' a dominant status within a within a human or other sufficiently brainy individual animal's neural "actention selection serving system" (The ASSS is an alternative to brain or neural system that has been expediently 'truncated to the max' to form of two capitals that are situated right in the middle of the acronym EAVASIVE).
More ÆPTly put and more completely explained:
Ambiadvantageous (~EAVASIVEness introducing or increasing) mutations not only led to new or more powerful adaptive ways of "paying exploitative actention" to environmentally present evolutionary factors of "opportunity type"!
They typically also reinforced not so much the preexisting capacity (emerged early in the phylogeny of fauna) to filter out and remain adaptively inactentive to innocuous or relatively insignificant current circumstantial or past conditioned-in sources of stimulation (most generally and conventionally referred to as "selective attention") as much as they reinforced the closely related and likewise ancient (in the phylogeny of animals) capacity to remain inactentive to distressfully significant circumstantial and/or no longer circumstantial conditioned-in sources stimulation — neural messages that in most circumstances would be destined to motivate a maladaptively paid actention of distress-type unless synaptically sequestered (as in prevented from being synaptically relayed toward triggering a distress-specific actention module (corresponding neural circuitry).
Some of these "pioneers of our EAVASIVE traits (or trait complexes)" would surely also have impressed mating partners and mating rivals in rudimentary artistic ways; i.e. with skills that we now associate with "The Arts" — e.g. drumming/humming/singing, dancing, and sculpting/carving and painting (only much later with abstract symbolic or phonetic writing).
The fate of less EAVASIVE ('less modern') family groups of hominine individuals who happened to be neighbors to a by a momentous EAVASIVE mutation as if souped up 'sept' (hence had one of our common ancestral breeding pairs as members) were typically "sealed".
[Here, or in context of ÆPT, "sept" suits being used as an efficient pointer to a small extended family group.]
However, the fate of such neighboring and 'EAVASIVEness poor' septs did not get sealed until the 'extra EAVASIVEness enabling' mutation had become carried by all adult of the sept in which it had occurred.
In our relatively recent phylogeny mutations that conferred and 'EAVASIVE edge' become fixed or resulted in an intra-tribal selective sweep by involving all possible ways that mating rivals could have competed with each other. After such selective sweeps within septs had been completed did such momentous mutations have extended repercussions by way of successive almost domino-effect-like' usurpings of distinctly less 'EAVASIVEly endowed' septs of nonetheless often closely related septs or simians/hominines/humans.
Even though Neanderthals and Denisovans may conceivable have been more intelligent than our with them contemporary main ancestors were, 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 hominine/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 EAVASIVE traits given that ditto mutations occurred) that have manifested as, for example:
1. An increasingly upright and well-balanced bipedalism 'paid for' by a concomitantly narrowed pelvis that made getting out from the womb into a guaranteed to be more or less traumatizing (SH imploring and because of pre-evolved neural functions SH-inducing) and CURSES incurring gauntlet.
Some of these momentous mutations may well have been pleiotropic in such a way that they caused babies to be born both extra early with bigger brains/craniums. However, long previously evolved endoopiate-releasing neural mechanisms and other relevant neural or neurohormonal functions came to the rescue —
neural functions that serve to prevent maladaptive distress by means of a release of endogenous opioids have existed since very early on in the evolution of animals.