WORK IN PROGRESS

Caveat lector: IANAB. (I suggest that instead of reading this, you might prefer to read some citations from https://en.wikipedia.org/wiki/Behavioral_modernity, e.g. Hill et al.'s "The Emergence of Human Uniqueness: Characters Underlying Behavioral Modernity".)

Minimal universal distinguishing originating features

(If this whole section becomes unengaging, try skipping to The List, below. For experts, I imagine the main part that might be interesting is the end of the list, so maybe try reading the list in reverse order.)

Motivations

This attempts to list all the features that make humans human. Needless to say this list will be very incomplete. Some motivations:

• What is the human niche?
• What set humanity off on its runaway evolution toward what we have been in the last few e5 years? What were the core drivers that drove that evolution?
• What is the core nature of humanity? This is something that we create and choose, but our self-creating and self-choosing wants to be informed by what we are.

The boundary of humanness

In the spirit of barely-examples, this list tries to describe the boundary between human and non-human. We could easily characterize humanity as "the species that builds skyscrapers". This is a good description--important and clear. But it's not minimal--that is, it derives from some other feature/s that is simpler, evolutionarily prior, a subset; in this case, "builds skyscrapers" derives (somehow) from iterative/recursive technology, iterative/recursive science, and large-scale intent-sharing. Since it isn't a minimal distinguishing universal, it is less good at helping us understand

1. what makes us able to build skyscrapers--the underlying generators of mightiness;
2. why us--i.e., what, if anything, makes us different from other animals;
3. and how--i.e., why and how did human evolution go down this path--what makes the mighty mind?

Instead we try to go closer to the boundary between human and non-human, closer to the transition. (But we won't shy away from making abstract hypotheses about the core minimal differences / earliest divergences between humans and non-humans.) Items on this list would ideally say that

1. all humans have this feature, and
2. no other species has this feature, and
3. this feature is minimal.

Since we're near the boundary, there will be many exceptions. We'll relax these criteria, and consider "almosts". We especially allow exceptions in chimps and other species closely related to humans. On the other hand, if non-human primates lack a feature but humans and some non-primates have the feature, it might also be interesting. That is, primate exceptionality within animalia, and human exceptionality within primates, are both relevant. (Less interesting would be a feature that many species share, or that is scattered throughout both primates and non-primates.)

See Brown's list of human universals. His list contains many things that are too downstream for this list (e.g. "poetic lines demarcated by pauses"), some things that are too vague (e.g. "culture"), and also many things that are not unique-ish to humans (e.g. "affection expressed and felt").

Note that many features of humans will be unique to humans simply because humans have the greatest cognitive capacity of any species. For almost any activity that humans tend to engage in a lot, if that activity can be excelled at through greater cognitive capacity, then excellence at that activity will be unique to humans. Likewise for a kaleidoscope of behaviors downstream of cultural accumulation.

Focusing on upstream features

An exhaustive list of human differences is beyond my knowledge, but it would be very interesting. However, for the purposes of this list (that is, understanding the cores of what is human about humans), we can focus on features that are conceptually upstream/generatorward. For example, humans have shorter arms and longer legs compared to apes--but, besides not being a very distinguishing feature among all animals, this feature seems probably entirely explained by humans being non-arboreal and bipedal. Bipedalism is upstream of short-armedness. (I think.) Likewise, opposable thumbs are subordinated to manual dexterity. (I think.) (Since all such conclusions are uncertain and partial (maybe manual dexterity is only part of the reason for opposable thumbs), the full list would be interesting even for this purpose. And, we will list plenty of items that are probably downstream of other items, e.g. fine motor skills in speech organs, which are presumably downstream of language.)

Admitting facultative features

To include a feature on the list, we don't need to claim that most or all non-human species couldn't exhibit that feature. For example, humans are very exceptional in copying patterns, e.g. making drawings of things they've seen. But we don't need to claim that there are not several other species that could perform similarly to humans, at least for the easiest versions of the copying task. The fact that humans do something much more than other animals implies that humans have a heightened ability and/or innate bias and/or environmental inducement to do that task.

Focusing on origins

Many might brush this sort of investigation aside, saying:

This list is not very relevant. The items are all explained very simply: cultural accumulation plus high cognitive capacity.

For example, language, science, and complex technology are all simply downstream consequences of accumulation plus intelligence; large brains and neoteny are just inputs to intelligence. But this is quite unsatisfactory.

First of all, it's just not a very good description. "Cognitive capacity" is pretty vague and homogeneous-sounding, whereas humans definitely have cognitive tasks we are much better and much worse suited to. There are strong ties between different cognitive capacities, but there's also a lot of interesting structure of implication and dependence between different cognitive capacities, and with aspects of morphology or habitat.

Second, it doesn't explain how the process started, and why it started with our ancestors.

Third, it doesn't explain which evolutionary forces interacted, in what order, and how. If language enables cultural transmission, then why did we get language in the first place? Or if cultural transmission was already on the rise, what enabled it mechanically, and what induced it evolutionarily?

Fourth, it doesn't explain why the process continued and continues unabated, taking us to extremes--why is there such a cliff in the fitness landscape?

Amphicausal hypotheses of origination

From "The Lion and the Worm":

I'm wary of relying on explanations in terms of runaway processes, not because the dynamic is implausible, but because I don't know how to make simple deductions from them; when, for instance, does an autocausation hypothesis / basin-finding hypothesis predict a dichotomy, vs. a spectrum produced by some controlling factor being distributed continuously on a spectrum (e.g. predator pressure)? Literally any feature could be autocausal if there's runaway recursive perceptual mate selection.

Language enables cultural transmission; a cultural inheritance incentivizes language. So which came first? Neither. They came together, both gradually--perhaps. Or maybe there was an order. But there are many plausible hypotheses. Getting a complete picture is plausibly just totally infeasible. But the question is still interesting, and I think some interesting conclusions can be drawn (and further questions asked) by reasoning about the logical consistency of various hypotheses, and testing them against the data.

Character syndromes

If we describe characters or selection pressures as "amphicausal", we are speaking of individual characters or pressures. For example, we might say that {language, speech organs, imitation, cultural transmission, tool-making} are all reciprocally causal with each other, creating a fully-connected feedback network between five separate items. Once the feedback loop has gotten going, removing any one character or pressure wouldn't much disrupt the species evolution from falling down the cliff in the fitness landscape. Put another way, the chain reaction of selection pressures is robustly self-sustaining.

In this case, it's skew to reality to talk about the five separate characters, each with arrows pointing to every other character. We should just say, there's one thing: the character syndrome, the conjuction of all these characters. The character syndrome is autocausal.

(I made up "character syndrome", but see Günter Wagner's work. Really, "character" can refer to character syndromes; but see below on articulations of possibilityspace.)

Initiatory, but-for, and driving selection pressures

(Roughly: initiatory = sufficient at the start; driving = sufficient during rapid change; but-for = necessary during rapid change)

An initiatory selection pressure is one that first tips a species over into falling over a cliff / rolling down into a basin in the fitness landscape. For example, we might hypothesize that at first, there was a selection pressure on hominids to perform better at persistence hunting, which applied pressure to have higher visual acuity, which applied pressure to have a greater capacity to process visual information, which applied pressure to expand the cerebral cortex. Then later, due to spillover increased general cognitive capacity, hominids were better at making associations between vocal calls and predator attacks, which increased the pressure to make different calls for different situations... and then a whole set of tasks that benefit from increased cognitive capacity all reinforced each other. We got launched into a character syndrome made of multiple selection pressures, but it was starting by a single selection pressure.

A but-for selection pressure is one that, if it suddenly vanishes, causes the character syndrome to stop evolving or regress. For example, consider that the peacock's tail may have first evolved to scare predators. Then later, it was the subject of runaway perceptual sexual selection. We might hypothesize that during the runaway evolution, IF, hypothetically, holding everything else the same, the females completely stopped selecting mates based on the appearance of their tail, THEN the tail would stop becoming more elaborate and would even become less elaborate. The perceptual selection is a but-for pressure.

A driving selection pressure is one that, if all the other selection pressures vanished, still keeps driving the evolution--it nevertheless can by itself sustain the ongoing character syndrome evolution. For example, consider that hominids had many fitness-increasing applications of their greater intelligence, and therefore many sources of pressure towards greater intelligence. But we might hypothesize that IF, hypothetically, all those selection pressures vanished (no persistence hunting, no complex language, no coalition building, ...) EXCEPT that cultural transmission through regularizing imitation continues as before, THEN hominids would nevertheless continue increasing in intelligence. Cultural transmission (and reception) is a driving pressure, according to this hypothesis: it alone is enough to more than pay back the increased metabolic costs, even without the other benefits of increased intelligence.

Other articulations of possibilityspace?

We want to describe the process (direction of change) and structure (telic dependencies) of evolution. We do this by pointing at characters that change, and pressures that these changes respond to. E.g. we say "brains got bigger", perhaps "in response to a need to outwit other humans". These descriptions blur together; for example, we might not distinguish "the ensemble of environmental features that set up persistence hunting as a task" from "hominids had an upright gait, less hair, forward-facing binocular vision, high cognitive capacity, high empathetic modeling, and so on", and instead just say "hominids became persistence hunters"; "is a persistence hunter" is both a response to part of a niche, and also a character (/ character syndrome).

Either way, we are trying to describe the fitness landscape around a species, from various angles: environments (hotness, wetness, soil, stone); predators, prey; genes, gene complexes, regulatory DNA, GRNs; traits such as limbs, organs, subsystems (immune, circulatory, nervous), claws, fangs, fur, bones, pigmentation, muscles; tasks, behaviors; abstract things like intelligence, vision (see Bergson's "L'Évolution créatrice"), sociality, neoteny; intraspecific interactions (fighting, perceptual selection). And so on. What other ways can we describe fitness landscapes--the adjacent possibilities, and the fitnesses there--in terms that are joint-carving? How can we systematize these descriptions--e.g., is there a general library of geometric motifs that describe the sort of local fitness landscapes seen in evolution?

Not The List

Some features that won't appear on the list below:

• Territorial. Although humans are territorial, many non-human animal species are also territorial; humans are neither exceptionally territorial nor exceptionally non-territorial.
• Venomous. Humans aren't venomous, and non-venomousness is not exceptional.
• Binocular vision. Many species have binocular vision--generally, hunters. This is a borderline feature, and could have shown up on the list. It's relevant for understanding what humans are and where we come from; but it's not distinctively human enough.
• Heightened emotions.
  • I thought that humans have the widest range of emotions and emotional expressions.
  • I assume many animals feel and behave according to fear and anger. Also pleasure.
  • Then I did a bit of googling and the picture isn't very clear to me. See wiki. Animals seem to behave bored, surprised, sympathetically, and so on.
  • Maybe disgust is heightened and more widely applied: many animals behave disgustedly (avoiding feces, rotting meat, etc.), but humans do so to a wider range of stimuli. See "Evaluating the Presence of Disgust in Animals".
  • Some other animals express what seems like gratitude, though maybe that's restricted to social animals. See here.
  • Maybe some social emotions are unique-ish to humans, such as pride, shame, guilt, embarassment, and contempt. What about trust, suspicion, and betrayal?
  • Presumably humans are more communicatively expressive about emotions.
• Hunter-gatherer.
  • Although hominids having been hunter-gatherers is one important thing to understand about them, it's a widespread kind of behavior among omnivorous species.

As described above, the list below isn't a list of interesting features of humans; it's a list of minimal-ish universal-ish distinguishing-ish features of humans.

The List

Please note: this is NOT extensively researched. These are provisional notes, not reliable claims. They're roughly arranged FROM concrete/narrow/clear/morphological/synchronic TO abstract/broad/unclear/behavioral/evolutionary.

If you know of things that should be on the list, or interesting unlisted exceptions, please let me know.

• Bipedal.
  • Walking almost exclusively on two limbs and do stuff with their arms.
  • Downstream of persistence hunting (efficient running, head held high to watch prey), or maybe tool-making (hands free).
  • There are various exceptions to the non-rule that only humans are bipedal. See wiki. E.g. kangaroos, many birds, many archosaurs; sometimes bears, dogs.
• Extreme visual acuity.
  • Humans have among the best detail-discerning vision among animals, and are in some ways pretty close to the physical limits of image resolution.
  • Many animals have wider fields of view. I assume there are some animals with slightly better range-detail vision, like maybe eagles.
• Fine motor skills.
  • Balance (for bipedalism).
  • Extreme manual dexterity.
    • Humans are the best.
    • Maybe partly exapted from arboreality / scansoriality.
    • Others: racoons, other apes, octopuses.
  • Speech organs.
    • Wide range, speed, and complexity of sounds produced.
    • Downstream of language.
    • Others: parrots, cetaceans (whales, dolphins). See wiki vocal learning.
• Hairless/furless.
  • Maybe downstream of persistence hunting, for purposes of staying cool.
  • Others: water-dwellers, reptiles, elephants, naked mole-rats.
• Large brains.
  • Humans have the largest brains among mammals, accounting for body size (e.g. "The allometry of brain size in mammals").
  • (Probably this is the case among all animals. Also there are more things to say about allometry, e.g. humans have a relatively larger prefrontal cortex.)
• Hidden estrus.
  • Men generally can't tell when a woman is ovulating. This is exceptional.
  • Others: vervet monkeys, maybe some other primates.
• Menopause.
  • Adult women eventually stop being fertile and then stop menstruating.
  • "Only a handful of species are believed to escape this seeming inevitability. They include female orcas, three other toothed whale species—belugas, narwhals and short-finned pilot whales—and according to a recent study, chimpanzees from one population in western Uganda." source
• Altricial.
  • Humans are very helpless at birth, and for a long while afterward.
  • Others: rodents, marsupials, primates, cats, dogs, passerine birds, owls, hawks.
• Neotenous.
  • Adult humans retain some childlike features, especially compared to other primates.
  • However, neoteny is allegedly common, so I don't know what to make of this. It's at least a local tendency relative to primates.
  • Neoteny might be downstream of self-domestication / self-niche-construction / resource abundance; other domesticated animals neotenize. It might be downstream of perceptual sexual selection. It might be downstream of selection for ability to learn (hence take advantage of cultural transmission).
• K-selected.
  • Humans generally have fewer children and invest more in raising children.
  • Others: elephants, whales, parrots, terns, eagles.
  • Humans might be exceptional in the amount of paternal investment--paternal uncertainty (hence investment, and non-infanticide) is one of the hypothesized reasons for hidden estrus.
• Dominator exploitation.
  • See The Lion and the Worm.
  • Between predator and parasite, there's something else: a beast that puts a creature in a situation where the creature does not die, but does not thrive, and its efforts go to benefit the beast.
  • Examples: serf (feudal lord), slave (slaveowner), wage slave (exploitative employer), governmental subject (government), military subject (military); Gervais-Losers, such as the floor manager in a factory described in Jackall's Moral Mazes, vs upper management; an abused/abusive lover; a cult member (cult leader who fosters social / emotional dependence).
  • Animals more or less don't do this. Parasitoids might sort of be a class of examples. Ants "farm" aphids, but aphids aren't agents and so can't really be exploited.
• Heightened expression of social emotions.
  • (See the discussion in the previous section, Not The List.)
• Tools.
  • See "Tool Use in Animals: Cognition and Ecology" by Sanz, Call, Boesch for more and more reliable info.
  • Many animals use tools. But humans are unique or almost unique in:
    • Making composite tools, i.e. tools make of multiple heterogeneous elements. A bed of multiple sticks isn't composite because it's all just sticks. A handaxe made of a stick, a shaped stone axehead, and binding fibers, is composite.
    • Transporting tools to the location where they'll be used. (But chimps do this, and octopuses might pick up a shell in warm water to carry over to cold water.)
    • Metatools, i.e. using tools to fashion other tools. (Crows and chimps do sequential tool use, i.e. using tools to obtain other preexisting tools. IDK if they do proper metatools.)
  • It's unclear what we want to mean by tools here. For example, do "morphological tools" such as claws or fingers count? Do we allow any use, or do we more specifically mean some purely functional (for its kinetic causal effects on other objects) or adaptive (non-instinctive) use? If we aren't specific enough, we'd have to admit that for example bowerbirds, in making their courtship displays, are transporting tools and making a "composite".
  • big difference. not just cultural-- we do large de novo thigns angd modificaitons. design thinking. complex designs. mental simulations. iterated things. holding things in mind.

tools Tool Use in Animals: Cognition and Ecology highly integrated: shelter, permanent shelter, shoes and other clothes, jewelry, vehicles, ... combining multiple heterogeneous pieces planning to reuse tools--putting them back in the shed

WORK IN PROGRESS

The more speculative section of the list

• The alien predator trophic niche.

varied foraging

complex extractive foraging https://www.sciencedirect.com/science/article/abs/pii/S0732118X1400049X https://link.springer.com/referenceworkentry/10.1007/978-3-319-19650-3_3104 https://link.springer.com/article/10.1007/BF02436709 https://pubmed.ncbi.nlm.nih.gov/24344962/

adaptive goal-sharing adaptation niche-expansion niche. escape, invasion long bout of reasoning that leads to significant actaion. but portia hunter spider... others? reshape environ. but beaver following orders; bicameral; other-modeling theory of mind modifying beahvior in order to teach ? being helpful

humans imitate details without knowing why; chimps throw away details. Hill etal suggest this is because they are taking the demonstrations as adversarial; where humans take it as benevolent, optimized to help. another thing is just a prior on copying more--this helps cultural transmision, but in particular is selected for if there's some store fo knowledege that is not so obvious why it is good--chestertons' fencese. some animals do teach: https://lalandlab.wp.st-andrews.ac.uk/files/2015/08/Hoppitt_et_al_TREE_2008.pdf

domesticating animals

traicking. empathietical modeling, hunting. but all predators do this?

wider range/ larger terrotiriy

greater meaning / subgoal transference to abstractions (things, features..); speculation...

music; dance; see those posts... scavenging

empathy, theory of mind

cheat detection

war

mental simulation. (but portia spiders. also predators like lions or whatever--sneakiness is a kind of theroy of mind. also predator evasion.)

niche construction niche

emotional crying

has an animal ever modulated its behavior 1 month later--with causal specificity (excluding learning)...

face recognition cheat recognition

adaptive art, drawing . caves

niche constrauction . inheritance. do beaverse inherit?

territoriality

social. nake molerats largest coordinated goal-sharing. wolves, orcas, lions, other hunters; leaf-cutter ants and other eusocial guys, naked mole rats...

remebering things / ppl that aren't there. caring about htem . but, elephants

sexual dimorphism

war.

coalition building

macroparasitism

abundance

self-domestication--weeding violence / discord / rebellion high paternal investment

https://en.wikipedia.org/wiki/Behavioral_modernity https://en.wikipedia.org/wiki/Hunting_hypothesis

Klein, R. G. 1999. The human career: human biological and cultural origins

food sharing across time? altruism? vampire bats...

concoius evolution

sedentary, agricultural. domesticating animals

https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis swimming? hairlnsseness? https://en.wikipedia.org/wiki/Timeline_of_human_evolution https://en.wikipedia.org/wiki/Language_development https://en.wikipedia.org/wiki/Steven_J._Dick#Intelligence_Principle https://en.wikipedia.org/wiki/Conscious_evolution https://en.wikipedia.org/wiki/Cooperative_eye_hypothesis https://en.wikipedia.org/wiki/Evolution_of_human_intelligence https://en.wikipedia.org/wiki/Evolutionary_models_of_food_sharing https://en.wikipedia.org/wiki/Gathering_hypothesis https://en.wikipedia.org/wiki/Grandmother_hypothesis https://en.wikipedia.org/wiki/Human_accelerated_regions https://en.wikipedia.org/wiki/Human_jaw_shrinkage https://en.wikipedia.org/wiki/Human_skeletal_changes_due_to_bipedalism https://en.wikipedia.org/wiki/Human_vestigiality https://en.wikipedia.org/wiki/Hunter-gatherer https://en.wikipedia.org/wiki/Hunting#Paleolithic

Third party punishment maybe Writing Other regarding Food transfer to non kin Cooperative with non kin. generally helping nonkin-- food, teaching, ... Long adult life homosexuality? Communicate about something not there Specialization Norms Space like barrter, i.e. thing for thing Hetero barrter . Adaptive that is (as opopsed to symbionts). Though maybe just kin care. No also inter tribe Intra group behavioral regulation Ultra social. Public good. Good in dictator games

wider ranging territory

invasion vs niche expansion?

analogis, copying patterns, eg say visual patterns.