What part of consciousness is social?

I think a lot of questions about consciousness fall into one of two categories:

• What is it, that is, what features does it have, what states of consciousness are there, what are reasonable tests of whether something is conscious or not (given that we can't directly experience any consciousness but our own)?
• How does it happen, that is, what causes things (like us, for example) to have conscious experiences?

Reading that over, I'm not sure it really captures the distinction I want to make.  The first item deals in experiments people know how to do right now, and there has been quite a lot of exciting work on the first type of question, falling under rubrics like "cognitive science" and "neural correlates of consciousness".

I mean for the second item to represent "the hard problem of consciousness", the "Why does anyone experience anything at all?" kind of question.  It's not clear whether one can conduct experiments about questions like this at all and, as far as I know, no one has an answer to that isn't ultimately circular.

For example, "We have consciousness because we have a soul" by itself doesn't answer "What is a soul?" and "How does it give us consciousness?" or clearly suggest an experiment that could confirm or refute it.  Instead, it states a defining property (typically among others): A soul is something which gives us consciousness.  The discussion doesn't necessarily end there, but if there's an answer to How does consciousness happen in it, it's not in the mere assertion that souls give us consciousness.

Similarly, if we substitute more mechanistic terms like "quantum indeterminacy" or "chaos of non-linear systems" or whatever else for "soul" in "We have consciousness because ...", we haven't explained why that leads to the subjective experience of consciousness or provided a way to test the assertion.  We may well be able to demonstrate that some aspect or another of consciousness is associated with some structure -- some collection of neurons, one might expect -- where quantum indeterminacy or chaos plays a significant role, but that doesn't explain why that structure correlates with consciousness rather than being just another structure along with the gall bladder, earlobe or whatever else.

If we were able to pinpoint some complex of neural circuits that fire exactly when a person is conscious, or perhaps more realistically, in a particular state of waking consciousness, or consciousness of a particular experience, it would be tempting, then, to say "Aha! We've found the neural circuits that cause consciousness," but that's not really accurate, for a couple of reasons.

First, correlation doesn't imply cause, which is why we speak of neural correlates of consciousness, not causes.  Second, even if there's a good case that the neural pattern we locate really is a cause -- for example, maybe it can be demonstrated that if the pattern is disrupted the person loses consciousness, as opposed to the other way around -- we still don't know what is causing a person to have the subjective experience of consciousness.  We can talk with some confidence about patterns of neurons firing, or even of subjects reporting particular experiences, but we can't speak with confidence about people actually experiencing things.

If we didn't already know that subjective experiences existed (or, at least, I know my subjective experiences exist), there's nothing about the experiment that would tell us that they did, much less why.  All we know is that if neurons are firing in such-and-such a state, the subject reports conscious experiences.

Since we do experience consciousness, it's blindingly obvious to us that the subject must be as well, but again that just shifts the problem back a level: We're convinced that we have found something that causes the subject to experience what we experience, but that doesn't explain why we experience anything to begin with.  If we were all "philosophical zombies" that exhibited all the outward signs of consciousness without actually experiencing it, the experiment would run exactly the same -- except that no one would actually experience it happening.

That's more than I meant to say about the second bullet point.  I actually meant to explore the first one, so let's try that.

Suppose you're hanging out in your hammock on a pleasant afternoon (note to self: how did I let the summer go by without that?).  You hear the wind in the trees, maybe birds chirping or dogs barking or kids playing, or cars going by, or whatever.  You are alone with your own thoughts, but for a while even those die down and you're just ... being.  Are you conscious?  Unless you've actually drifted off to sleep, I think most people would answer yes.  If someone taps you on your shoulder or shouts your name, you'll probably respond, though you might be a bit slow to come back up to speed.  If it starts to rain, you'll feel it.  If something makes a loud noise and you manage to regain your meditative state, you're still liable to remember the noise.

On the other hand, it's something of a different state of consciousness than much of our usual existence.  There's nothing verbal going on.  There's no interaction with other people, none of the constant evaluation  (much of which we're generally not aware of) concerning what people might be thinking, or whether they heard or understood you, or whether you're understanding them, or what their motives might be, or their opinions of you or others around, or what they might be aware of or unaware of.  You're not having an inner conversation with yourself or that jerk who cut you off at the intersection, and there's little to no self consciousness, if you're only focusing on the sensory experience of the moment (indeed, this is a major reason people actively seek such a meditative state).

I've become more and more convinced over time that we often underestimate how conscious other beings are.  I don't subscribe to the sort of literal panpsychism that holds that a brick has a consciousness, that "It is something (to a brick) to be a brick".  I doubt this is a particularly widely held position anyway, so much as the anchor at one end of a spectrum between it and "nothing is actually conscious at all".  However, I am open to the idea that anything with a certain minimum complement of capabilities which can be measured fairly objectively, including particularly senses and memory, has some sort of consciousness, and, as a corollary, that there are many different kinds or components of consciousness that different things have at different times.

For example, a hawk circling over a field waiting for a mouse to pop out of its burrow likely has some sort of experience of doing this, and if it spots a mouse, it has some sort of awareness of there now being prey to pursue with the goal of eating it or, if there are no mice, an awareness of being hungry.  This wouldn't be awareness on a verbal, reflective level we experience when we notice we are hungry and tell someone about it, but something more akin to that "I'm relaxing in a hammock and things are just happening" kind of awareness.  I also wouldn't claim that this awareness is serving any particular purpose.  Rather, it's a side effect of having the sort of mental circuitry a hawk has and being embodied in a universe where time exists -- another mystery that may well be deeply connected to the hard problem of consciousness.

I think this is in some sense the simplest hypothesis, given that we have the same general kind of neural machinery as hawks and that we can experience things happening.  It still presupposes that there's some sort of structural difference between things with at least some subjective experiences and things with no such experiences at all, but that "something" becomes a fairly general and widely-shared capacity for sensing the world and retaining some memory of it rather than a specialized facility unique to us.  The difference between us and a hawk is not that we're conscious and hawks aren't, but that we have a different set of experiences from hawks.  For the most part this would be a larger set of experiences, but, if you buy the premise of hawks having experiences at all, there are almost certainly some that they have but we don't.

Which leads me back to the title of this post.

I suspect that if you polled a bunch of people about consciousness in other animals, you'd see more "yes" answers to "is a chimpanzee conscious" or "is a dog conscious" than to "is a hawk conscious" or "is a salmon conscious".  Some of this is probably due to our concept of intelligence in other animals.  Most people probably think that chimps and dogs are "smart animals", while hawks and salmon are "just regular animals".

However, I think our judgment of that is strongly colored by chimps and dogs being more social animals than hawks or fish (even fish that school are probably not social in the same way we are -- I'd go into why I think that, but this post is already running a bit long).  It doesn't take much observation of chimps and dogs interacting with their own species and with humans to conclude that they have some awareness of individual identities and social structure, the ability to persuade others to do what they want (or at least try), and other aspects of behavior that are geared specifically toward interaction with those around them.  Other animals do interact with each other, but social animals like chimps, dogs and humans normally do so on a daily basis as a central part of life.

This social orientation produces its own set of experiences beyond "things are happening in the physical world" experiences like hunger and an awareness that some potential food just popped out of a burrow.  I think it's this particular kind of experience that we tend to gravitate toward when we think of conscious experience.  More specifically, self-awareness is often held out as the hallmark of "true consciousness", and I think there's a good case that self-awareness is closely connected to the sort of "what is that one over there thinking and what do they want" calculation that comes of living as a social animal.

To some extent this is a matter of definition.  If you define consciousness as self-awareness, then it's probably relatively rare, even if several species are able to pass tests like the mirror test (Can the subject tell that the animal in the mirror is itself?).  However, if you define consciousness as the ability to have subjective experiences, then I think it's hard to argue that it's not widespread.  In that formulation, self-awareness is a particular kind of subjective experience limited to relatively few kinds of being, but only one kind of experience among many.

The human perspective and its limits

A couple more points occurred to me after I hit "publish" on the previous post.  Both of them revolve around subjectivity versus objectivity, and to what extent we might be limited by our human perspective.


In trying to define whether a kind of behavior is simple or complex, I gave two different notions which I claimed were equivalent: how hard it is to describe and how hard it is to build something to copy it.

The first is, in a sense, subjective, because it involves our ability to describe and understand things.  Since we describe things using language, it's tied to what fits well with language.  The second is much more objective.  If I build a chess-playing robot, something with no knowledge of human language or of chess could figure out what it was doing, at least in principle.

One of the most fundamental results in computer science is that there are a number of very simple computing models (stack machines, lambda calculus, combinators, Turing machines, cellular automata, C++ templates ... OK, maybe not always so simple) which are "functionally complete".  That means that any of them can compute any "total recursive function". This covers a wide range of problems, from adding numbers to playing chess to finding cute cat videos and beyond.

It doesn't matter which model you choose.  Any of them can be used to simulate any of the others.  Even a quantum computer is still computing the same kinds of functions [um ... not 100% sure about that ... should run that down some day --D.H.].  The fuss there is about the possibility that a quantum computer could compute certain difficult functions exponentially faster than a non-quantum computer.

Defining a totally recursive function for a problem basically means translating it into mathematical terms, in other words, describing it objectively.  Computability theory says that if you can do that, you can write a program to compute it, essentially building something to perform the task (generally you tell a general-purpose computer to execute the code you wrote, but if you really want to you can build a physical circuit to do the what the computer would do).

So the two notions, of describing a task clearly and producing something to perform it are, provably, equivalent.  There are some technical issues with the notion of complexity here that I'm going to gloss over.  The whole P = NP thing revolves around whether being able to state a problem simply means being able to solve it simply, but when it comes to deciding whether recognizing faces is harder than walking, I'm going to claim we can leave that aside.

The catch here is that my notion of objectivity -- defining a computable function -- is ultimately based on mathematics, which in turn is based on our notion of what it means to prove something (the links between computing and theorem proving are interesting and deep, but we're already in deep enough as it is).  Proof, in turn, is -- at least historically -- based on how our minds work, and in particular how language works.  Which is what I called "subjective" at the top.

So, is our notion of how hard something is to do mechanically -- my ostensibly "objective" definition -- limited by our modes of reasoning, particularly verbal reasoning, or is verbal/mathematical reasoning a fundamentally powerful way of describing things that we happened to discover because we developed minds capable of apprehending it?  I'd tend to think the latter, but then maybe that's just a human bias.



Second, as to our tendency to think that particularly human things like language and house-building are special, that might not just be arrogance, even if we're not really as special as we'd like to think.  We have a theory of mind, and not just of human minds.  We attribute very human-like motivations to other animals, and I'd argue that in many, maybe most, cases we're right.  Moreover, we also attribute different levels of consciousness to different things (things includes machines, which we also anthropomorphize).

There's a big asymmetry there: we actually experience our own consciousness, and we assume other people share the same level of consciousness, at least under normal circumstances, and we have that confirmed as we communicate our consciousnesses to each other.  It's entirely natural, then, to see our own intelligence and consciousness, which we see from the inside in the case of ourselves and close up in the case of other people, as particularly richer and more vivid.  This is difficult to let go of when trying to study other kinds of mind, but it seems to me it's essential at least to try.

Is recognizing faces all that special?

I've seen some headlines recently saying that fish can be taught to recognize human faces.  It's not clear why these would be circulating now, since the original paper appeared in 2016, but it's supposed to be newsworthy because fish weren't thought to have the neural structures needed to recognize faces.  In particular, they lack a neocortex (particularly the fusiform gyrus), or anything clearly analogous to it, which is what humans and primates use in recognizing faces.  Neither do the fish in question normally interact with humans, unlike, say, dogs, which might be expected to have developed an innate ability to recognize people.

The main thesis of the paper appears to be that there's nothing particularly special about recognizing faces.  As a compugeek, I'd say that the human brain is optimized for recognizing faces, but that doesn't mean that a more general approach can't work.  It makes sense that we'd have special machinery for faces.  Recognizing human faces is important to humans, though it's worth pointing out that there are plenty of people who don't seem to have this optimization (the technical term is prosopagnosia).

The authors of the paper also point out that recognizing faces is tricky:

[F]aces share the same basic components and individuals must be discriminated based on subtle differences in features or spatial relationships.

To be sure that the fish are performing the same recognition task we do, though presumably through different means, the experimental setup uses the same skin tone in all the images and crops them to a uniform oval.  Frankly, I found it hard to pick out the differences in what was left, but my facial recognition seems to be weaker than average in real life as well.

This is interesting work and the methodology seems solid, but should we really be surprised?  Yes, recognizing faces is tricky, but so is picking out a potential predator or prey, particularly if it's trying not to be found.

The archerfish used in the experiments normally provide for themselves by spitting jets of water at flies and small animals, then collecting them when they fall.  This means seeing the prey through the distortion of the air/water boundary, contracting various muscles at just the right rate and time, and finding the fallen prey.  For bonus points, don't waste energy shooting down dead leaves and such.

Doing all that requires the type of neural computation that seems easy until you actually try to duplicate it.  Did I mention that archerfish have a range on the order of meters, a dozen or so times their body length? It's not clear why recognizing faces should be particularly hard by comparison.

Computer neural networks can recognize faces using far fewer neurons than a fish has (Wikipedia says an adult zebrafish has around 10 million).  Granted, the fish has other things it needs to do with those neurons, and you can't necessarily compare virtual neurons directly to real ones, but virtual neurons are pretty simple -- they basically add a bunch of numbers, each multiplied by a "weight", and fiddle the result slightly.  Real neurons do much the same thing with electrical signals, hence the name "neural network".

It doesn't seem like recognizing shapes as complex as human faces should require a huge number of neurons.  The question, rather, is what kinds of brains are flexible enough to repurpose their shape recognition to an arbitrary task like figuring out which image of a face to spit at in order to get a tasty treat.

Again, is it surprising that a variety of different brains should have that kind of flexibility?  Being able to recognize new types of shape in the wild has pretty clear adaptive value, as does having flexible brain wiring in general.  Arguably the surprise would be finding an animal that relies strongly on its visual system that couldn't learn to recognize subtle differences in arbitrary shapes.

And yet, this kind of result does seem counterintuitive to many, and I'd include myself if I hadn't already seen similar results.  Intuitively we believe that some things take a more powerful kind of intelligence than others.  Playing chess or computing the derivative of a function is hard.  Walking is easy.

We also have a natural understanding of what kinds of intelligence are particularly human.  We naturally want to draw a clear line between our sort of intelligence and everyone else's.  Clearly those uniquely human abilities must require some higher form of intelligence.  Language with features like pronouns, tenses and subordinate clauses seems unique to us (though there's a lot we don't know about communication in other species), so it must be very high level.  Likewise for whatever we want to call the kind of planning and coordination needed to, say, build a house.

Recognizing each other's faces is a very human thing to do -- notwithstanding that several other kinds of animal seem perfectly capable of it -- so it must require some higher level of intelligence as well.

Now, to be clear, I'm quite sure that there is a constellation of features that, taken together, is unique and mostly universal to humanity, even if we share a number of particular features in that constellation with other species.  No one else we're aware of produces the kind of artifacts we do ... jelly donuts, jet skis, jackhammers, jugs, jujubes, jazz ...  or forms quite the same kind of social structures, or any of a number of other things.

However, that doesn't mean that these things are particularly complex or special.  We're also much less hairy than other primates, but near-hairlessness isn't a complex trait.  Our feet (and much of the rest of our bodies) are specialized for standing up, but that doesn't seem particularly different from specializing to swing through trees, or gallop, or hop like a kangaroo, or whatever else.

Our intuitions about what kind of intelligence is complex, or "of a higher order" are just not very reliable.  Playing chess is not particularly complicated.  It just requires bashing out lots and lots of different possible moves.  Calculating derivatives from a general formula is easy.  Walking, on the other hand, is fiendishly hard.  Language is ... interesting ... but many of the features of language, particularly stringing together combinations of distinct elements in sequence, are quite simple.

What do I mean by "simple" here?  I mean one of two more or less equivalent things: How hard is it to describe accurately, and how hard is it to build something to perform the task.  In other words, how hard is it to objectively model something, in the sense that you'll get the same result no matter who or what is following the instructions.

This is not necessarily the same question as how complex a brain do you need in order to perform the task, but this is partly because brains have developed in response to particular features of their environment.  Playing chess or taking the derivative of a polynomial shouldn't take a lot of neurons in principle, but it's hard for us because we don't have any neurons hardwired for those tasks.  Instead we have to use the less-hardwired parts of our brain pull together pieces that originally arose for different purposes.

Recognizing faces seems like something that requires a modest amount of machinery of the type that most visually-oriented animals should have available, and probably available in a form that can be adapted to the task, even if recognizing human faces isn't something the animal would normally have to do.  Cataloging what sorts of animals do it well seems interesting and ultimately useful in helping us understand our own brains, but we shouldn't be surprised if that catalog turns out to be fairly large.

Can we prove a dog is happy?

The previous post talked about qualia, or subjective experiences, but why should we care?  This being a matter of philosophy, there are a variety of answers to that, starting with "Why care about anything?" but nonetheless, there seems to be something significant about the question.  At least from my own subjective point of view.

For one thing, it seems like one of those fundamental questions.  How can we come to a complete understanding of the universe without understanding how we experience it?  Perhaps more than that, there are ethical concerns.  If we wish to increase happiness or we do not wish to cause unnecessary suffering in the world, we should understand what happiness and suffering are.  Outward appearances will only tell us so much.  It would be good to have more reliable indicators, or at least to know how reliable the ones we have are.

The problem with subjective experiences, though, is that they are subjective.  I can be well convinced that my own subjective experience is real.  Sentio ergo sum -- I feel, therefore I am.  There are several reasons for me to believe that someone else's feelings are real: I can see their reactions, they can tell me, and we know that humans have, for the most part, essentially the same neural apparatus.

Nonetheless I cannot know for sure what another person's feelings are in the same way that you and I could both put the same object on a balance scale and agree on its mass.  Each of the common-sense indications I just gave can fail.  Someone may not react visibly to a feeling or experience, or I may not catch the reaction.  They may not be able to tell me for any number of reasons.  Different people can have different ranges of feeling -- what seems intense to me might seem like nothing special to you, or vice-versa.

From a purely philosophical point of view we don't know for sure that having the same kind of neural pathway means having the same kinds of experiences.  Perhaps the ability to experience requires both a certain type of pathway and something else intangible that not everyone has.   Even if there is no such intangible, we're still far from knowing what physical pieces are associated with experience, though we do have some clues.  Without knowing just what pathways gives rise to subjective experience we have no way to be sure everyone has it.

When we go beyond human experience to other species, which react differently, can't verbalize their experiences (or at least not in ways we can presently understand), and have clearly different neural circuitry, we have even less to go on.  We can presume that a dog wagging its tail and barking when its human returns is happy, but it's always possible that dogs have simply co-evolved with us for long enough that they are able to act happy when that would be to their advantage (most people with dogs would dispute this, I expect).

Artificial constructs are even more problematic.  If I build a robot that avoids walls even if you push it toward one, it's easy to say "it doesn't like walls" because it's acting like a sentient being that disliked walls would, but it seems a much bigger step to say "it avoids walls because it experiences negative emotions when it's near one", particularly when we can point to the exact code that causes it to avoid walls.

Even if the code for the control system is extremely complex or has gone through some sort of machine learning process to develop an avoidance of walls, so that we couldn't point to exactly what was making it avoid walls, it still seems hard to argue that the robot is feeling emotions.  If incomprehensible code were the basis of sentience, there would be a lot of sentient software around.

When it comes to what we generally refer to as inanimate objects, the best we can say is that we have no reason to believe that a rock feels pain if we smash it with a hammer.  Nothing in our understanding of how we feel pain seems to apply to something like a rock.  Even so, how can we really know?


But how do we know anything?  We have no way of knowing whether we really live in a universe where the laws of physics hold.  It's possible that tomorrow things dropped will fall up instead of down.  Some theories of cosmology assign a non-zero (but still exceedingly small) chance that we live in such a universe.

In the absence of certain knowledge all we can do is try to build a coherent framework and constantly test and adjust the assumptions it rests on, a process we call "science".  From a scientific point of view we can figure out what sort of neural structures correspond with the subjective experiences that people report.  We can assess whether other organisms have such structures and even whether a particular combination of hardware and software has something functionally equivalent.

We can tell whether something's reactions to various stimuli are consistent with it having such capabilities, based on what people have reported.  We can conclude from that that it's likely or unlikely that the organism or construct we're examining is experiencing feelings, but we can never know for sure, no matter what philosophical machinery we develop for understanding qualia.

But this is nothing new.  Recently it was announced that gravitational waves had finally been detected, stemming from the collision of two black holes over a billion years ago.  The chain of inferences that rests on is mind-boggling.  A more accurate statement would have been "In two separate places, specially constructed instruments registered a signal that indicated that test masses had moved, over a distance much less than the size of an atom, in a way that indicated that space-time had been distorted in a way consistent with the collision of two black holes over a billion light-years away.  We feel confident about this because we believe that science works in general and we're convinced by a large web of observations and theoretical conclusions that the observable universe is billions of years old and billions of light-years in extent, black holes exist and, consistent with a distinct but overlapping web of observations and theoretical conclusions, in certain cases they should produce detectable gravitational waves.  We have also done extensive measurements to convince ourselves that the detectors are in fact detecting gravitational waves and not just trucks driving by ..."

And that would be the short version.  The full version fills textbooks and takes entire careers to grasp even a small portion of.

If science can accept that, can it come to accept that a dog is happy?

Not exactly.  The sticking point here is not whether we can accept a long chain of inference like "People report feeling happy when certain neurons are firing in certain ways, they behave in certain ways when this is happening, dogs have analogous neural pathways, and these tend to fire when dogs are engaged in behavior analogous to that of happy people, and/or people report that the dogs seem happy."  That's not a problem, particularly not compared to the detection of gravitational waves.

The problem is that science depends fundamentally on objective, repeatable measurements of numbers.  Happiness is subjective, and happiness is not a number.  Science can get quite close to measuring happiness, but it's up to us to decide where to go from there -- just like with any other scientific result.

Qualia, or why do we experience anything at all?

Today I'd like to discuss a topic which has baffled (at least some) philosophers for quite some time and which I am even more ill-qualified to address than usual.  Since I'm giving general impressions from general ignorance I'll be citing a few well-known examples without attribution.  You can find a good summary here, or it least it seemed like a good one to me.  Rest assured I'm not claiming to be doing any original work here, just ... conjecturing.

The term qualia has come to encompass experiences, and in particular subjective experiences.  For example, what is it like to see the color red, or what is it to be a bat.  Such experiences seem to be subjective, in that the experience depends, at least in principle, on who's experiencing it.  To take a very old example, cliche but no less valid for being cliche, I have no obvious way of knowing whether you experience the color red in the way I do.  Perhaps you experience it the way I experience the color blue, and vice versa, or perhaps you experience it some completely different way.

For that matter, how do I know that you experience anything?  If you and I are at an intersection, stopped at a red light, I can see you react to the light turning green, but that doesn't mean that you had the same experience I did of seeing a red light and then a green light.  I assume that you experienced the sensation of something red and then something green, and that the color red seemed essentially the same way to you as it did to me, but how would I know?

Suppose you were actually in a self-driving car browsing the news on your phone.  You didn't see the light at all.  Rather, the car's cameras recorded the light changing and the car's control system caused the car to go when the light turned green.  I'm perfectly comfortable saying "The car saw the light change and drove through the intersection when it turned green", anthropomorphizing the car, but that doesn't mean I think the car experienced the colors red and green in anything like the way you or I would (or at least, I think you would).

Trying to account for distinctions like this in some objective way has been referred to as "the hard problem of consciousness", as opposed to easier, more empirical problems like "How does the brain record memories?" or "To what extent are we conscious of our own decisions?"

In some sense it's quite likely that all experiences are distinct.  If I see a red paint chip today and then again tomorrow, I will almost certainly have different associations each time.  The first time might put me in mind of a stop sign, or blood, or a red apple.  The second time I might be more focused on whether it's the same paint chip I saw yesterday.  Likewise, you will almost certainly have different associations than I will even if we're looking at the same chip.

And yet, we would probably all agree that we are experiencing seeing something red, and that it feels like something to have that experience.   Even if there's no emotional response, you're still having some sort of experience.  How do we account for that?

Suppose we could account for every firing of every neuron in the nervous system (including the optic nerve, which is actually doing quite a bit of processing before the signal even gets to the brain).  Have we accounted for the experience?  Suppose that after decades of research we compile an exhaustive list of experiences and how they correlate to brain activity.  We bring in a new subject and scan their neural activity.  Pointing at a display, we say "That pattern of firing always occurs in response to seeing the color red".  We can say "that person is experiencing the color red", but how, exactly, do we know that for sure?

It's not hard to imagine what kind of data would back this up.  We hook hundreds of subjects from all over the world and all walks of life up to our highly-advanced brain scanner, flash colors at them and note the results.  We may even ask them to describe what they're experiencing.  When we see the same patterns for our new subject it's a reasonable inference that their brain is processing the color red, and it's reasonable to expect that if we ask them what they're experiencing, their answer will involve the color red.

That's probably good enough for a cognitive scientist, but not a philosopher.  The philosopher may well insist that you don't know what the subject experienced, but only how they would answer a question.  They -- and for that matter any of your other subjects -- might just as well be philosophical zombies who exhibit all the expected behaviors and responses without actually experiencing anything.  We may know intuitively, but we can't prove that the test subjects aren't just like the self-driving car, only on a more elaborate level.


There are a couple of ways out of this.  One is to deny that qualia exist in any well-defined way.  From a logical point of view, this seems quite plausible.  We can talk about the abstract concept of redness, but in real life we don't experience redness in the abstract.  We experience a particular something red at a particular place and time.  That feels a particular way at that place and time, and quite possibly nothing has ever felt quite the same before or ever will.  Maybe we should just stick to our knitting and figure out what happens in real brains in response to real stimuli.  We can still generalize and define abstractions, but if we want an objective description of the world we have to start with objective data.

And yet, we still experience things, subjectively, each of us (or at least I'm pretty sure about me).

So how do we distinguish between a person at a stop light and a self-driving car?  Maybe we don't need to make a strong distinction.  Maybe we're ... not so different.

There's no particular reason, beyond our innate sense of specialness, to assume that only human beings can have experiences.  If we see a hungry dog, our intuition tells us the dog is experiencing hunger.  Our intuition is probably right.  The dog may not be having exactly the same kind of experience we do, but there's no reason to assume it's a philosophical zombie that only looks like it's experiencing hunger.

One way of handling this is to assert that along with the physical properties of the world -- mass, position, velocity and so forth -- there is an experiential component that's completely distinct but which we might still be able to reason about.  Perhaps we will even discover laws that govern it and develop a comprehensive theory of experience.

One objection to this approach is that it seems to imply panpsychism, the idea that everything has consciousness.  There are already schools of thought that believe exactly that, but the concept doesn't sit particularly well in materialist circles (materialist in the philosophical sense).

However, this seems misguided.  If consciousness in the sense of being able to experience qualia is a property in a way similar to mass being a property of things, that doesn't mean that everything has to have that property.  Just as photons are massless, there's no contradiction in saying a rock is unconscious.

Rather than stating that everything has consciousness, we are asserting that objects can have consciousness, and we are trying to investigate under what circumstances that happens.  However, we are explicitly punting on the question of how it has consciousness.  We are saying that when the conditions are right "it just does", just as when a particle interacts with the Higgs field it has mass* (I believe physics has a more detailed account of this than "it just does", but at some point even physics has to make some base assumptions).

From that point of view it's still reasonable to say that a rock has no feelings or consciousness, but a human does, a dog does and just possibly a self-driving car has some limited degree of consciousness as well.  Moreover we may be able to prove that in the scientific sense of having a coherent theory and data to support it.  If so, it seems this theory will look a lot like a purely material explanation of memory, attention and other aspects of consciousness, together with an assertion that when certain of these are present, the thing in which they are present experiences qualia.

What is it to be a self-driving car?  Probably not much, but perhaps something.

* [That's not a really rigorous way to phrase that, but I don't know well enough to give a better one --D.H.]

What is syntax and how much does it matter?

From a computing point of view, when we say "syntax" we're largely talking about "parse trees".  A parse tree breaks a text into components, which are in turn broken down into sub-components, and so forth down to basic pieces analogous to words and punctuation in natural languages.  The largest unit is the root of the tree, and the tree branches wherever you break a larger component into smaller.  As I've said before, this is just like breaking a sentence down into, say, a noun phrase and a verb phrase, breaking the noun phrase into a determiner and a noun, and so forth.

I've also noted that this isn't the only way to break sentences down.  In fact, if you search for sentence diagramming, you're more likely to turn up material on the Reed-Kellog system, and there has been quite a bit of research on dependency grammars.  Both of these have tree structures implicit in them, but you could argue that pretty much any formal system does.  The more relevant point is that they don't emphasize constituency, that is, what's a part of what.  They're more interested in what modifies what, or more generally, what depends on what.

So, what is this syntax that we speak of?  I previously defined it as "the study of how words fit together in sentences".  Wikipedia has it as "the set of rules, principles, and processes that govern the structure of sentences in a given language, specifically word order", which seems pretty similar except for the emphasis on word order.  What sparked this post, however, was a statement in an Nat Geo blog post on killer whales (a.k.a. orcas, but that's a separate discussion), that

Language in the strict sense means syntax, which means that word placement determines meaning. So, “Put the blue pillow on the red pillow” means something different than, “Put the red pillow on the blue pillow.” Same exact words, different order. That’s language. Some dolphins and some apes have the ability to understand human syntax.

Killer whales are dolphins—the biggest ones. I am not aware of whether they understand human syntax. 

Initially I was struck by the simplicity of "word placement determines meaning" followed by a convincing example.  Later, I wondered how well that notion (or "specifically word order" in the Wikipedia definition) applies to languages with free word order.  Certainly order matters in narrating a story, or in figuring out which noun a pronoun might refer to, but in many languages ordering is more a matter of emphasis than meaning.

But now what strikes me about this passage is the emphasis on understanding.  This tends toward a more operational definition of syntax, for example, can you understand the difference between Put the blue pillow on the red pillow and Put the red pillow on the blue pillow.

Intuitively it seems like understanding the difference between Canis hominem mordet (dog bites man) and Canem homo mordet (man bites dog) would be much the same task, even though the word order is the same for both of those sentences.  So what are we really after here?

Fundamentally the problem to solve is communicating information reasonably efficiently and accurately.  I almost said "communicating concepts", but this depends on what concepts the parties involved can understand.  I may have a perfectly concise way to say "The square of the hypotenuse is equal to the sum of the squares of the legs", but that's not going to help much if my listener doesn't know what a hypotenuse is.

There's one other piece here, though.  Many species are capable of communicating a repertoire of messages, and even of learning new messages for that repertoire.  Vervets famously have different alarm calls for their main predators (leopards, eagles, pythons, and baboons).  They can also adjust to individuals that consistently make the wrong call, recognize their offspring by their calls and possibly invent new calls for new dangers.  Some dogs can be taught names for dozens of different objects which they can then retrieve by name.  Neither, however, seems to have language in the same way we do.

To establish that something unusual is going on, as with theories of mind, we need some sort of combinatorial explosion, that is, a situation in which a small number of basic pieces generate a very large number of possibilities.

For example, if we have a red pillow, a blue pillow, a red box and a blue box, and any one of them can be put to the left of, to the right of, in front of, behind, on top of or under any of the others, there 72 different combinations (red pillow to the left of blue pillow, red pillow to the left of red box ... blue box under red box), though since "red pillow to the left of blue pillow" is the same as "blue pillow to the right of red pillow" there are really only 36 possibilities, but 72 ways of expressing them.

The number of possibilities increases as the square of the number of objects.  If you double the number of objects, there are four times as many possibilities.  Similarly, if you add a new directional relation, say "to the left of and in front of", you've added as many possibilities as there are pairs of objects.  If you add a new kind of relation, say "close to" vs. "far from" (leaving aside whether you can place a red pillow far above a blue box), you've multiplied the total number of possibilities by a new factor.

For example, if you have ten objects, twelve directional relations and "touching", "close" and "far apart", you now have 1620 possibilities.  You haven't added much to the original setup, but there are now 45 times as many possibilities as before.  It's easy to see how you could make this much, much bigger just by adding more different kinds of distinctions.

Imagine an experiment where your subjects are (somehow) taught signs for the four objects and six directional relations, and then (somehow) required to communicate a particular arrangement.  Say subject 1 is shown an arrangement that subject 2 can't see, and if it can convince subject 2 to create the same arrangement they both get a reward.

If your test subjects can handle the original setup of 36 possibilities, it's possible that they learned the examples you gave by rote and guessed on ones they hadn't already seen.  You could control for that by making sure the two subjects are shown different examples, but if you want to run several trials and there are only 36 possibilities to choose from, it's hard to be sure that any significant syntax is involved.

On the other hand, suppose you have a pair of subjects that can handle the small setup, and then you add a new object.  After they see a couple of examples involving the new object they can handle unfamiliar setups involving it about as well as they can handle the originals.  You then give a few examples of a new relation (say, diagonal as above) and their performance doesn't suffer.  You then show a new kind of relation (say, distance as above) and they can still handle it.  You've now got a reasonably large space of arrangements to choose from and you can easily do repeated trials without repeating the exact arrangements.

At that point, I'd say you can infer that the communication system has some way not only of distinguishing "red pillow on top of blue pillow" from "blue pillow on top of red pillow", but distinguishing "A on top of B" from "B on top of A" in general.  I'll claim that at that point you can reasonably say there is syntax in some form, as well as some form of "abstract relation".


This is not the same as saying the experimental subjects have the same kind of language as we do.  You can solve the problem in the experiment with any way of selecting an directional relation, a first object, a second object and an distance relation.  That could be as simple as listing the four in order, as "red-pillow blue-pillow in-front-of close".

Handling new kinds of relations or constraints (e.g., put the pillow fuzzy side up) doesn't require much more syntax.  If the system can distinguish one relation/constraint from another, then something like "direction: red-pillow in-front-of blue-pillow, distance: close, orientation: red-pillow fuzzy-side-up" packs in a lot of information, and it's easy to see how you would extend it.


Where does that leave constructs that we tend to think are unique to human language, including dependent clauses like that I saw yesterday in The movie that I saw yesterday was two hours long?  I'm not sure how to set up an experiment like the previous one that could distinguish a language with dependent clauses from one without.  After all, I could just as well say I saw a movie yesterday.   That movie was two hours long.  This requires using that in its sense as a determiner to link the sentences together in a particular way.  This is still a pretty powerful construct, but it doesn't require tucking I saw the movie yesterday in as a direct modifier to movie.

From this point of view, the distinction between having dependent clauses and not having them is not particularly important.  This is in contrast to the computer science-y view that I've been most familiar with, where there is a huge distinction between recursive structures -- ones that can contain sub-parts of the same general form as the structure they're part of, such as sentences acting as clauses inside larger sentences -- and non-recursive structures, which can't.  One important distinction from that point of view is that there are in principle infinitely many possible structures -- sentences, say -- if recursion is allowed but only finitely many if it's not.

This is true in the mathematical world, but it's less important when considering real communication.  On the one hand, there are only finitely many sentences that are short enough for a real person to say or understand.  In practice, we rarely nest more than a few levels deep.  When we do, the result is often pretty hard to understand.

On the other hand, "finite" as a mathematical concept includes numbers large enough to be infinite for any practical purpose.  In fact, I've argued, almost all numbers are vastly too big for us to comprehend, let alone to occur in any natural context.  In practice, this means that even if you have only a handful of template sentences to fill in and you can't nest sentences within sentences, you can still end up with a gargantuan number of possible sentences -- and there's no reason you can't use more than one sentence in a conversation (technically, stringing sentences together can be expressed as recursion, but let's not get into that).



What if you can't do a controlled experiment to figure out how complex a communication system is?  What if all the data you have is from observations in the wild?  What if you're not sure what part of the noises, gestures or whatever else you observe are or aren't significant?  The task is certainly harder, then, but maybe not infeasible.  You're still looking for signs of combinatorial explosion, particularly the ability to deal with novel combinations of factors in a way that requires communication, that is, where

• Different individuals have different information,
• they need to share that information,
• the exact information to share varies within a combinatorially large space of possibilities, and
• the individuals involved are able to act usefully in ways they couldn't have without sharing the information.

The first two and the last are easy to find in any number of situations (arguably the second and last points are just different ways to say the same thing).  When a vervet sees a baboon, it shrieks out the alarm call for baboons and all the vervets skedaddle, you've met all but the third point.  From observation, it's reasonably clear that there isn't a combinatorially large space of possibilities.  There is a relatively small and constant set of calls.

Human communication clearly satisfies all four points.  Most of the sentences in this post, for example, are not only unique to the post but most likely unique to all human communication (I'm going to guess that the phrase "vervets skedaddle" is fairly rare in its own right -- it didn't turn up when I googled it with quotes, though that should soon change ...).  This is not something I consciously aimed for, just a natural consequence of writing reasonably long sentences in English (or any other natural language for that matter).

The interesting question is whether anyone else meets the third point.

Pan proiiciens

Humans have several unique qualities (and many more not-so-unique), but one that may not come readily to mind is that we throw things, and we throw them very well.  No other animal we know of could come remotely close to doing this, or this, or this.  Even an average human's throwing abilities are far beyond anything else in the natural world.  If I said that I'd seen someone throw a ball 50 meters, no one would think twice.  If I said that I'd seen a horse throw a ball 50 meters, the most likely response would probably be "No, you didn't", maybe followed by "How??"

If you think about it, it's actually somewhat surprising that humans would be unique when it comes to throwing things.  It's a very useful skill.  If you can bring down a small mammal with a well-aimed rock, you'll eat much better than if you have to run it down.  Even if you're a very good runner-downer, it still takes way less energy to throw a rock.  Throwing a rock can also get a high-hanging fruit out of a tree (if not easily).  Throwing is a good way to get something you're carrying up onto a high ledge that you can then get to with all your limbs free, and so forth.  You'd think something would have stumbled on it before our ancestors did.

On the other hand, a lot of body plans just aren't that well suited to throwing.  Birds have one set of limbs serving as landing gear and for locomotion when not airborne, and the other given over to wings.  That leaves the head and beak as all-purpose picker-uppers, severely limiting throwing potential.  Birds can throw things by picking them up and then heaving the head and letting go, but not very far or forcefully.

Fish and other sea creatures live in a viscous medium where throwing is not particularly useful.  Most mammals have all four limbs specialized for walking, running, jumping and so forth, leaving them in much the same spot as birds.  Lizards are also pretty well tied to the ground or other surface they're traveling on -- particularly the limbless ones, to say nothing of actual snakes (snakes are closely related to lizards, but there are also some proper lizards that lack limbs).

There's an obvious common thread here: To throw effectively you need a free limb, one not specialized to supporting your weight.  You need hands, as opposed to front feet.  You don't need to be fully bipedal, though that clearly ought to help, but you do need to be able to grab something, stand up on your hind limbs and let fly.

There aren't many animals in that category, but several primates are, by virtue of having hands (and feet, and tails) adapted to grabbing and swinging from tree branches instead of always walking on all fours.  Putting all this together, perhaps it's not so surprising that throwing would have only evolved recently, in a branch of the primate family tree, itself relatively recent.

It is a principle of evolution that behavior tends to change first, and then anatomy follows.  First certain fish started coming up out of the water, whether to escape from other fish who couldn't or to move from a shallow, drying-up pond to a deeper one, or for whatever reason. Later came Tiktaalik and its kin with pectoral fin bones (and other features) better adapted to life out of water.

Once the new niche was established on land, there was plenty of selection pressure to reshape the body for living on land, and eventually lose the older adaptations for water living entirely.  More strictly speaking, the new behavior of coming up on land meant that fish with more land-adapted bodies could have better survival chances.

In the case of primates throwing, it's not that other primates don't throw.  Some species of monkeys are well-known to throw excrement at others of their species, and chimps will throw things as a threat.  It doesn't seem to matter much to them what they throw, but it will generally be branches and occasionally rocks.  Chimps don't show signs of throwing with the same purposes we do, but it's significant that some sort of throwing behavior is established in our near relatives.  It's therefore plausible, though not certain, that it was also established in our common ancestors.

While chimps are known to hunt, and are known to throw things, and are known to be reasonably intelligent, they are not known to throw for purposes of hunting.  This is not completely shocking, considering what they hunt -- small monkeys -- and how they hunt them.  The strategy is to go in as a group, block off escape routes and send one member of the hunting party in for the kill.  Rock throwing would probably not help much in such a situation.  You'd have to encumber a hand carrying a rock up into the trees, and then you'd only have one rock, a bunch of branches in the way, and a monkey that would not be well-inclined to stay still in the path of a hurtling rock.

But imagine a tribe of ancestral chimps a couple of million years ago venturing out of the forest.  These wouldn't be exactly like today's chimps, of course, but today's chimps appear to resemble these ancestors much more closely than we do, so we can consider them ancestral chimps here.  In 1993, William Calvin laid out a hypothesis that a good way for such creatures to get food would be to stake out a water hole and go after the herds that gathered there to drink -- as several other predators do.

Naturally, herds of gazelles and such are adapted to dealing with predators around water holes.  The main strategy is to stampede away, which works well, except that any animal that trips or falls is likely to be trampled by the herd and left behind as an easy meal.  This actually works reasonably well for the herd as a whole (from an individual's view, if you have this behavior you're more likely to be one of the survivors than if you don't), and it works for the hunters as well.  It just doesn't work particularly well for the particular animal left behind.

Now suppose you hit upon a way to make a herd stampede, and at the same time make one of its members stumble and likely be trampled.  That would work even better for you, though again not so well for the unlucky victim.  Calvin's idea is that there's an easy way to do this, that those ancestral chimps could have done with the mental and physical abilities they had: Throw a reasonably-sized rock into the herd.  If it hits one member, that member will stumble, the herd will startle and, with a bit of luck, trample the stumbler.   This doesn't have to happen every time, just enough to make it noticeably easier to get food from the herds gathered at the water hole.

At that point, we're off to the races.  Any change, whether in behavior or anatomy,  that improves throwing force or accuracy, will make for better hunting and better-fed primates.  Richard Young cites paleontological evidence to support a claim that exactly this happened during the past couple million years, that the body, and the hand in particular, became better and better suited to throwing (and to clubbing, another area where we excel).  Doing these well requires a number of changes from the long-fingered, short-thumbed tree-branch-hooking hands of the rest of the chimp family.

Calvin, for his part, speculates that the famous Archeulean hand axe was actually an improved weapon to throw into a herd, as it would be more likely to cut into the prey's hide and cause it to instinctively collapse, making it more likely to be trampled.  As always, this doesn't imply that the hunters were thinking it through in that much detail.  It's enough that throwing a sharp rock works better than throwing one that isn't, and that some in the population had an innate proclivity for chipping away at rocks and so making them sharper.

It's been argued repeatedly that, if we weren't the ones doing the classifying, or weren't so subject to a certain prideful feeling of distinctness from the rest of nature,  we would be classified in the same genus as chimps and bonobos.  Either they would be Homo troglodytes and Homo paniscus, or we would be Pan sapiens.  Under the latter scheme, those savanna-dwelling rock throwers might best be called Pan proiiciens -- throwing Pan, the name Pan being taken from the Greek god of the forest, used to designate the forest-dwelling chimps and bonobos.  Except these particular Pan would be leaving the forest.

Behavior drives anatomical change, but anatomy limits behavior.  Just as only some fish had the right anatomy to even try moving on land, only some animals had the right kind of body to try throwing things.  Primates happened to be close enough, again likely because their hands had already adapted for something else besides walking, something that allowed for grabbing and flinging.  This is a common pattern in evolution.  It used to be called pre-adaptation, but that gives the impression that, for example, primate hands evolved for grabbing tree branches so that they could later evolve for throwing and clubbing.  That's not how it works, so the ungainly but unbiased term exaptation is preferred.

There is another interesting point that Calvin makes.  It's not enough to have the anatomy.  You need to be able to control it.  It takes around a tenth of a second for our bodies to carry out a conscious command.  To throw a projectile accurately [as we do now, as opposed to lobbing rocks into a herd -- D.H. Sep 2015], you need to time your movements within about a hundredth of a second.  Once you've decided to throw something, it's far, far too late to make adjustments as you go along.  You have to have the whole program ready to go ahead of time, adjusted for where your target is, or rather where it will be when the projectile reaches it.  Calvin speculates that this sort of plan-ahead was re-purposed into our control structures for things like language.

I'm not sure I quite buy this.  I doubt that throwing is the only thing in evolutionary history that requires this sort of plan-ahead.  Surely when a hawk dives for a mouse or a cheetah jumps for a gazelle it is doing the same sort of thing under similar constraints.  Nonetheless, it's an interesting idea, and plausible in a general sense, that the original behavior change of throwing things would have brought on a host of other changes, in both behavior and anatomy, that led to wholly new behaviors like speech and large-scale planning (for lack of a better term for the type of planning that we do and other animals don't).

On the pace of change in human technology

Lately, I've been listening to the BBC podcast of A History of the World in 100 Objects.  The program is full of all sorts of illuminating information about the history of humanity, but I want to focus here on three of the eariler objects

• An Oldowan stone chopping tool found in the Olduvai Gorge in Tanzania, about 2 million years old
• An Archeulean stone hand axe, also found there, but about 1.2 million years old
• A Clovis spear point, found in Arizona, about 13,000 years old

At first glance, these seem pretty similar.  They're pieces of hard stone that have had pieces knocked off of them to make tools.  The hand axe and the spear point have the same general form, though the spear point is considerably smaller.  If you had to guess what kind of creature made each object, you might well think that the hand axe and the spear point were made by the same creature, or at least similar, while the chopping tool was made by something much less sophisticated.  But that's not quite the case.

All three objects were made by members of our genus, Homo.  That is, they were made by primates that walked upright like us and, at least by comparison with other primates, had skulls and teeth more or less like ours, and so on.  However, the humanoids who made the chopping tool were definitely not modern humans.

Why not?  First, they didn't look like us, even if they looked more like us than like other apes.  The chopping tool is found with the bones of Homo habilis, which, while it walked upright, had longer arms than us and a smaller skull, was considerably smaller overall, and showed a greater size difference between male and female than humans do.  If we'd seen a group of habilis out walking around, we would probably have thought "Those are interesting-looking apes.  Almost human, even." and not "Those people look weird."

Second, Homo habilis doesn't seem to have been able to make much else out of stone.  Yes, several other kinds of tools are found at the same site, but not many kinds, and all made basically the same way: Take a more-or-less hand-sized rock and knock a small number of chips off it.  The end result looks much like the original piece of stone.  In fact, it's also possible that what we see as a chopping tool is actually just the leftover and it's the sharp flakes that the makers were after.  Or they could have used both.  In any case, the formula is simple: Knock one rock with another, use what you end up with.

Despite appearances, it's also quite clear that the makers of the Archeulean hand axe were not human.  From skeletal remains, they were Homo ergaster (or African Homo erectus, depending on your classification).  To be sure, the tools found with them are the result of a more elaborate process than habilis's chopping tools.  After hammering the core stone with another stone to flake parts of it off, the stone is then worked with bone, wood or antler to refine the shape.  This gives longer, sharper edges than Oldowan tools have, and the hand axe is much more symmetrical than the chopper, but again, there are only a few basic tools in the toolkit, and this toolkit remains the same for hundreds of thousands of years.  [As one would expect from an area of active inquiry, there has been some new information about hand-axes and such since I first wrote this, but the basic picture is still a small repertoire of tools with little or no change for thousands of generations.  I may return to this topic ... --D.H. 15 Oct 2014]

The simplest explanation for the the Oldowan and Acheulean toolkits is that they were the product of instinct, not some general tool-making ability.

I think, if we weren't talking about human ancestry here, this would be an open-and-shut case.  Since we are, I suppose I should elaborate on that a bit.  Because the chopping tool and hand axe are being presented as early human tools, it's natural to look at them and think, especially in the case of the hand axe, "Of course.  They're too complex and sophisticated to be the result of instinct, and they were clearly meant to be used as tools.  That implies a mind capable of intention and forethought."

It's natural to think that, but all kinds of natural, common-sense conclusions turn out not to be true.  This is most likely one of them.

First, consider complexity.  It's hard to say how an Archeulean hand axe is any more complex than, say, a weaver bird nest, beehive or pufferfish circle, to take a few examples.  You could argue that weaving a nest, or making a beehive or circular pattern in the sand is merely a matter of performing a simple behavior repeatedly according to a predetermined recipe -- leaving aside how "simple" that might actually be -- but so too is hitting one rock with another in a symmetrical pattern.

Fair enough, but a hand axe is not just a passive structure.  It is a tool built to be used to help manipulate the environment to a particular purpose.  But other animals do this, too, without any evident abstract forethought.  While there are not a lot of examples of this, there are several well-known ones: a capuchin monkey using a stick to get at termites, for instance, or an otter using rocks to break open a shellfish.

There are even a few known cases of other animals making tools to be used.  Elephants will strip the bark off of branches to make a better switch for swatting flies.  Chimps will do likewise with termite-fetching sticks.  For that matter, building a nest or burrow is no better or worse an argument for forethought.  Both are built for future use.  This is not the same as building a particle accelerator, or even a well-fletched arrow, but it's clearly something.

And yet, there is no particular reason to think that a bird building a nest is consciously thinking "I will build this nest so that I can sleep and brood eggs here."  It's not out of the question, but it doesn't seem at all necessary to assume intent in order to explain the behavior.

In that light, the chopping tool and hand axe look like just another example of animal tool use, perhaps unique in the particular combination of making and using the tool, but not a huge leap from other animal examples.

Let me be clear that I'm not arguing that the Oldowan and Archeulean tools are the product of instinct because they are in some way "simple".  Modern archeologists have learned the "knapping" technique used to produce these tools, and it's harder than it might look.  Rather, I'm arguing that instinctive behavior is not necessarily simple, other animals do similarly complex things instinctively, and in both cases the behavior carries on, essentially unchanged, for generation after generation.

But hold on.  Couldn't we just as well say that the Clovis spear point is the product of instinct?  Sure, we know that we make tools intentionally, but maybe the Clovis people didn't.  The Clovis tool kit is remarkably uniform over the Americas, and most (but not all) finds comprise a handful of different designs of tools made by the same stone-knapping techniques as the hand axe and the chopping tool.

However, there are two big clues that this is not the case, and one even has to do with the title of this post.

First, the Clovis people came along well after humans began to disperse from Africa.  People alive today share a large number of common characteristics unique to humans, such as language with pronouns and other heavy linguistic machinery, music, art, jewelry and, of course, tool-making as we know it.  The most recent common ancestor of all people alive today lived somewhere in the vicinity of 50,000 years ago.

Genetic studies of modern Native Americans in North America show that they share a common ancestor at least as far back as the Clovis people and, of course, belong to the same family tree as everyone else.  There is no plausible way that the Clovis people were not ancestors of people alive today, and no plausible way that those ancestors are not descendants of the original human population.

Why would the Clovis artifacts seem to closely resemble those of habilis and ergaster, then?  Why no Clovis art, beyond a few markings on bone?  Why no evidence of jewelry, or other kinds of artifact found in European sites from thousands of years earlier?

A survey paper by Ryan Ellsworth of the University of Missouri puts forth a plausible explanation:  The Clovis people spread very quickly, over a period of a few hundred years, over a previously uninhabited area, which would explain the uniformity.  They were nomadic, and tended to camp at the kill sites of the megafauna (mastodons and such) that they brought down.  They would not have built permanent dwellings, much less villages or cities, would have had no reason to carry anything bulky and non-functional with them, and probably preferred easy-to-work but more perishable materials for any art or jewelry they did carry.  This is not too far from hunter-gatherer societies encountered in modern times [Much of this type of narrative has been called into serious question, but that'll have to go in a different post -- D.H Jan 2022].

There is still a lot to be learned about the Clovis culture, and there are several competing theories as to who arrived when and did what, but Ellsworth's hypothesis fits the known evidence and is in line with a fair bit of other work.  Even if that particular account doesn't turn out to be the definitive answer, there's no need to reach too far to explain why a population of behaviorally modern humans might leave traces such as we find for the Clovis people.

Which brings me to the second big clue, and the title: Clovis culture is succeeded immediately by a number of other cultures which show a steady development of tools, regional variations and, eventually, the full array of human artifacts, from cities with huge monuments to houses to carved beads.  This happens over a period of thousands of years, much, much too quickly to be explained by genetic change.  Even if some disaster had wiped out humanity in the Americas before Europeans arrived, we would know that these later artifacts were made by people, and the early ones by their ancestors.

In short, the rate of change by itself is enough to make it clear that a generalist tool-user was at work.

This still leaves plenty of questions unanswered.  What happened between Homo ergaster and Homo sapiens [and our cousins such as Denisovans and Neanderthals] to make that shift from instinctive behavior to cultural behavior, learned and passed down from generation to generation?  Why is it that, while other animals can learn new behavior, and to some extent transmit it, we only see this sort of ratcheting effect, of each generation building on the last, in our species?  How did civilization and technology develop in several branches of the human family tree independently, but not to any significant extent in others?  Why does the pace of technological change appear to be accelerating?  Will this continue?

All interesting questions, and I may get to them some time.  Or back to them.  I've had a couple of stabs at some of them already.

If language isn't an instinct, what is it?

Steven Pinker's The Language Instinct makes the case that humans, and so far as we know only humans, have an innate ability to acquire language in the sense we generally understand it.  Further, Pinker asserts that using this ability does not require conscious effort.  A child living with a group of people will normally come to learn their language, regardless of whether the child's parents spoke that language, or what particular language it is.  This is not limited to spoken languages.  A child living among sign language users will acquire the local sign language.  There are, of course, people who are unable to learn languages, but they are the rare exceptions, just as there are people who are completely unable to see colors.

There is, on the other hand, no innate ability to speak any particular language. A child of Finnish-speaking parents will not spontaneously speak Finnish if there is no one around speaking Finnish, and the same can be said of any human language.

This is noteworthy, even it if might seem obvious, because human languages vary to an impressive degree.  Some have dozens of distinct sounds, some only a handful.  Some have rich systems of inflections, allowing a single word to take thousands of different forms.  Some (like English, and Mandarin even more so) have very little inflection.  Some have large vocabularies and some don't (though any language can easily extend its vocabulary).  The forms used to express common concepts like "is", or whether something happened yesterday, is happening now or might never happen, can be completely different in different languages.

At first glance this variation may seem completely arbitrary, but it isn't.  There are rules, even if our understanding of them is very incomplete.  There are no known languages where, say, repeating a word five times always means the opposite of repeating that word four times.  There's no reason in principle there couldn't be such a language, but there aren't, and the probable reasons aren't hard to guess.

There's a more subtle point behind this: There is no one such thing as "communication", "signaling" or "language".  Rather, there are various frameworks for communication.  For example, "red means stop and green means go" is a system with two signals, each with a fixed meaning.  Generalizing this a bit, "define a fixed set of signs each with a fixed meaning" is a simple framework for communication.  A somewhat more complex framework would allow for defining new signs with fixed meanings -- start with "red means stop and green means go", but now add "yellow means caution".

Many animals communicate within one or the other of these frameworks.  Many, many species can recognize a specific set of signs.  Dogs and great apes, among others, can learn new signs.  Human language, though, requires a considerably more complex framework.  We pay attention not only to particular signs, but to the order in which they are communicated.  In English "dog bites man" is different from "man bites dog".  Even in languages with looser word order, order still matters.

Further, nearly all, if not all, human languages have a concept of "subordinate clause", that is, the ability to fold a sentence like "The boy is wearing a red shirt" into a sentence like "The boy who is wearing the red shirt kicked the ball."  These structures can nest deeply, apparently limited by the short-term memory of the speaker and listener and not by some inherent rule.  Thus we can understand sentences like I know you think I said he saw her tell him that.  As far as we can tell, no other animal can do this sort of thing.

This not to say that communication in other animals is simple.  Chimpanzee gestures, for example, are quite elaborate, and we're only beginning to understand how dolphins and other cetaceans communicate.  Nonetheless, there is reasonable evidence that we're not missing anything on the order of human language.   It's possible in principle that, say, the squeaks of mice are carrying elaborate messages we haven't yet learned how to decode, but mice don't show signs of behavior that can only be explained by a sophisticated signaling system.   Similarly, studies of dolphin whistles suggest that their structure is fundamentally less complex than human language -- though dolphins are able to understand ordered sets of commands.

In short, human languages are built on a framework unique to us, and we have an innate, species-universal, automatic ability to learn and use human languages within that framework.  Thus the title The Language Instinct.   Strictly speaking The Instinct to Acquire and Use Language would be more precise, but speaking strictly generally doesn't sell as many books.


This all seems quite persuasive, especially as Pinker puts it forth, but primatologist and developmental psychologist Michael Tomasello argues otherwise in his review of Pinker, straightforwardly titled Language is not an Instinct  (Pinker's book titles seem to invite this sort of response).  Tomasello is highly respected in his fields and knows a great deal about how human and non-human minds work.  I cited him as an authority in a previous post on theories of mind, for example.  Linguistics is not his area of specialization, but he is clearly more than casually familiar with the literature of the field.

Tomasello agrees that people everywhere develop languages, and that human languages are distinct from other animal communication systems, albeit perhaps not quite so distinct as we would like to think.  However, he argues that there does not need to be any language-specific capability in our genes in order for this to be so.  Instead, the simplest explanation is that language falls out as a natural consequence of other abilities, such as the ability to reason in terms of objects, actions and predicates.

To this end, he cites Elizabeth Bates' analogy that, while humans eat mostly with their hands, this does not mean there is an innate eating-with-hands capability.  People need to eat, eating involves moving food around and our hands are our tool of choice for moving things around in general.  Just because everyone does it doesn't mean that there is a particular instinct for it.  Similarly, no other species is known to cook food, but cooking food is clearly something we learn, not something innate.  Just because only we do it doesn't mean that we have a particular instinct for it.

This is a perfectly good point about logical necessity.  If all we know is that language is universal to humans and specific to humans, we can't conclude that there is a particular instinct for it.  But Tomasello goes further to assert that, even when you dig into the full evidence regarding human language, not only is there no reason to believe that there is a particular language instinct, but language is better explained as a result of other instincts we do have.


So how would we pick between these views?  Tomasello's review becomes somewhat unhelpful here.  First, it veers into criticism of Pinker personally, and linguists of his school of thought in general, as being unreceptive to contrary views, prone to assert his views as "correct" and "scientific" when other supportable views exist, and overly attached to the specialized jargon of their field.  A certain amount of this seems valid.  Pinker is skilled in debate, a useful skill that can cut both ways, and this can give the air of certainty regardless of how certain things actually are.  There is also mention of Pinker's former advisor, the famed linguistic pioneer and polemicist Noam Chomksy, but Pinker's views on cognition and language are not necessarily those of Chomsky.

Second, and one would have to assume as a result of the first point, the review takes on what looks suspiciously like a strawman.   In Tomasello's view Pinker, and those claiming a "language instinct" that is more than the natural result of human cognition and the general animal ability to signal, are generally concerned with mathematical elegance, and in particular the concept of generative grammar.

Generative grammar breaks language down into sentences which are in turn composed of a noun phrase and a verb phrase, which may in turn be composed of smaller parts in an orderly pattern of nesting.  This is basically the kind of sentence diagramming you may have learned in school [when I wrote this I didn't realize that there are several ways people are taught to analyze sentences, so I wrote "you learned in school", assuming everyone had had the same experience..  But of course there are several ways.  In some schemes the results look more like dependency graphs than parse trees, which sent me down a fairly eye-opening path.  So, sorry about that, but at least I ended up learning something].

Linguistic theories along these lines generally add to this some notion of "movement rules" that allow us to convert, say, The man read the book into The book was read by the man.  Such systems are generally referred to as transformational generative grammars, to emphasize the role of the movement rules, but I'll go with Tomasello here and drop the "transformational" part.  Keep in mind, though, that if a field is "basically" built on some familiar concept, that's just the tip of the iceberg.

A generative grammar, by itself, is purely syntactic.  If you call flurb a noun and veem a verb, then "Flurbs veem." is a grammatically correct sentence (at least according to English grammar) regardless of what, if anything, flurb and veem might actually mean.  Likewise, you can transform Flurbs veem into Veeming is done by flurbs and other such forms purely by moving grammatical parts around.

Tomasello questions whether the structures predicted by generative grammar even exist in all languages.  Generative grammar did happen to work well when first applied to English, but that's to be expected.  The techniques behind it, which come from Latin "grammar school" grammar by way of computing theory, were developed to analyze European languages, of which English is one.  Likewise, much of the early work in generative grammar was focused on a handful of the world's thousands of languages, though not necessarily only European ones.  There is an obvious danger in such situations that someone familiar with generative grammar will tend to find signs of it whether it is there or not.  If all you have is a hammer, the whole world looks like a nail.

From what I know of the evidence though, all known languages display structures that can be analyzed reasonably well in traditional generative grammar terms.  Tomasello asserts, for example, that Lakota (spoken by tribes in the Dakotas and thereabouts) has "no coherent verb phrase".   A linguist whom I consulted, who is familiar with the language, tells me this is simply not true.  The Jesuit Eugene Buechel was apparently also unaware of this when he wrote A Grammar of Lakota in 1939.

But perhaps we're a bit off in the weeds at this point.  What we really have here, I believe, is a set of interrelated assertions:

• Human language is unique and universal to humans.  This is not in dispute.
• Humans acquire language naturally, independent of the language.  Also not in dispute.
• Human languages vary significantly.  Again, not in dispute.
• Human language is closely related to human cognition.  This is one of Tomasello's main points, but I doubt that Pinker would dispute it, even though Tomasello seems to think so.
• Generative grammar predicts structures that are actually seen in all known languages.  Tomasello disputes this while Pinker asserts it.  I think Pinker has the better case.
• Generative grammar describes the actual mechanisms of human language.

That last is subtly different from the one before it.  Just because we see noun phrases and verb phrases, and the same sentence can be expressed in different forms, doesn't mean that the mind actually generates parse trees (the mathematical equivalent of sentence diagrams) or that in order to produce "The book was read by the man" the mind first produces "The man read the book" and then transforms it into passive voice.  To draw an analogy, computer animators have models that can generate realistic-looking plants and animals, but no one is claiming that explains how plants and animals develop.

Personally, I've never been convinced that generative grammars are fundamental to language.  Attempts to write language-processing software based on this theory have ended in tears, which is not a good sign.  Generative grammar is an extremely good fit for computers.  Computer languages are in fact based on a tamer version of it, and the same concepts turn up repeatedly elsewhere in computer science.  If it were also a good fit for natural languages, natural language processing ought to be considerably further along than it is.  There have been significant advances in language processing, but they don't look particularly like pure generative grammar rendered in code.  Peter Norvig has a nice critique on this.

Be that as it may, I don't see that any of this has much bearing on the larger points:

• Human language has features that are distinct from other human cognitive functions.
• These features (or some of them) are instinctive.

In putting forth an alternative to generative grammar, drawn from work elsewhere in the linguistic community, Tomasello appears to agree on the second point, if not the first.  In the alternative view, humans have a number of cognitive abilities, such as the ability to form categories, to distinguish objects, actions and actors and to define a focus of attention.  There is evolutionary value in being able to communicate, and a basic constraint that communication consists of signals laid out sequentially in time (understanding that there can be multiple channels of communication, for example saying "yes" while nodding one's head).

In this view, there are only four basic ways of encoding what's in the mind into signals to be sent and received:

• Individual symbols (words)
• Markers on symbols (for example, prefixes and suffixes -- "grammatical morphology")
• Ordering of symbols (syntactic distinctions like "dog bites man" vs. "man bites dog")
• Prosody (stress and intonation)

Language, then, would be the natural result of trying to communicate thoughts under these constraints.

It's quite possible that our working within these constraints would result in something that looks a lot like generative grammar, which is another way of saying that even if language looks like it can be described by generative grammar, generative grammar may not describe what's fundamentally going on.

On the other hand, this sort of explanation smacks of Stephen Jay Gould's notion that human intelligence could be the result of our having evolved  a larger brain as a side-effect of something else.  While evolution can certainly act in such roundabout ways, this pretends that intelligence isn't useful and adaptive on its own, and it glosses over the problem of just how a bigger brain is necessarily a smarter brain, as opposed to, say, a brain that can control a larger body without any sophisticated reasoning, or a brain less likely to be seriously injured from a blow to a head.

Likewise, we can't assume that our primate ancestors, having vocal cords, problem-solving ability and the need to communicate, would necessarily develop, over and over again, structurally similar ways of putting things into words.  Speaking, one could argue, is a significantly harder problem than eating with one's hands, and might require some further, specialized ability beyond sheer native intelligence.

There could well have been primates with sophisticated thoughts to express, who would have hunted more effectively and generally survived better had they been able to communicate these thoughts, but nonetheless just couldn't do it.  This would have given, say, a group of siblings that had a better way of voicing their thoughts a significant advantage, and so we're off to the races.  Along those lines, it's quite possible that some or all of the four encoding methods are both instinctive and, in at least some aspects, specific to language as opposed to other things the brain does.

Looking at the list of basic ways of encoding:

Associating words with concepts seems similar to the general problem of slotting mental objects into schemas, for example having a "move thing X from point A to point B" schema that can accept arbitrary X, A and B.  Clearly we and other animals have some form of this.

However, that doesn't seem quite the same as associating arbitrary sounds or gestures with particular meanings.  In the case of "move thing X from point A to point B", there will only be one particular X, Y or B at any given time.  Humans are capable of learning hundreds of thousands of "listemes" (in Pinker's terminology), that is sign/meaning pairs.  This seems completely separate from the ability to discern objects, or fit them into schemas.  Lots of animals can do that, but it appears that only a few can learn new associations between signs and meanings, and only humans can handle human-sized vocabularies.

Likewise, morphology -- the ability to modify symbols in arbitrary, conventional ways, seems very much language-specific, particularly since we all seem to distinguish words and parts of words without being told how to do so.  The very idea of morphology assumes that he sings is two words, not he and sing and s.

Ordering of symbols is to some extent a function of having to transmit signals linearly and both sides having limited short-term memory.  Related concepts will tend to be nearby in time, for example.  This is not a logical necessity but a practical one.  One could devise schemes where, say, all the nouns from a group of five sentences are listed together, followed by all the verbs with some further markers linking them up, but this would never work for human communication.

But to untangle a sentence like I know you think I said he saw her tell him that, it's not enough to know that, say I next to know implies that it's me doing the knowing.  We have to make a flat sequence of words into a nested sequence of clauses, something like I know (you think (I said (he saw (her tell him that)))).  Different languages do this differently, and it can be done different ways in the same language, depending on which wording we choose.  (He saw (her tell him that)), I know (you think (I said)).

Finally, prosody is probably closely tied to expressions of emotion.  Certainly SHOUTING WHEN ANGRY is related to other displays of aggression, and so forth.  Nonetheless, prosody can also be purely informational, as in distinguishing "The White House is large" from "The white house is large."  This informational use of prosody might well be specific to language use.
In each of these cases, it's a mistake to equate some widely-shared capability with a particular facility in human language.  There is more to vocabulary, morphology, syntax and prosody than simply distinguishing objects, changing the form of symbols, putting symbols in a linear sequence or speaking more or less loudly, and this, I believe, is where Tomasello's argument falls down.

Similarly, the ability to map some network of ideas (she told him that, you think I said it, etc.) into a sequence of words seems distinct from the ability to conceive such thoughts.  At the very least, there would need to be some explanation of how the mind is able to make such a mapping.  Perhaps that mechanism can be built from parts used elsewhere.  It wouldn't be the first time such a re-purposing has evolved.  Or it might be unique to language.

Most likely, then, language is not an instinct, per se, but a combination of pieces, some of which are general-purpose, some of which are particular to animal language, and some of which may well be unique to human language.  The basic pieces are innate, but the particular way they fit together to form a given language is not.

Try fitting that on a book cover.