Almost done now…
Finally, we come to the fourth of Tinbergen’s four questions. His framework for analyzing all biological phenomena has proven to be extremely useful. The first two questions represented the two static elements of Tinbergen’s model. They tell the “contemporary” accounts of the current form of a behavior in its present condition. For consciousness, that helped me develop my hierarchy by looking at the functions of consciousness, and then I saw that this hierarchy held up well as I went through a physicalist account of the mechanisms of consciousness. The next two questions move on to the dynamic elements, or the “chronicle” accounts that explain a biological phenomenon in terms of the sequence that got it there. In the last post, I looked at ontogeny, or the development of consciousness over a (human) lifetime. Now, we can look at the ultimate tale of consciousness—its phylogenetic history.
I noted at the end of my last post about ontogeny that I wasn’t sure how well my hierarchy would continue to hold up, but it was extremely exciting to see that the biological and psychological research into human development conformed perfectly well with my hierarchy. This was a great example of consilience where multiple streams of evidence are all pointing to the same thing. Now, it’s time for one final check. But before I can go through the details of the hierarchical development of consciousness, I have to lay the groundwork with a general overview of the phylogeny of life.
General notes about phylogeny
David Christian has perhaps developed the most well-known sweeping story of existence with his groundbreaking Big History project. He divides the history of the universe into eight fundamental thresholds.
That’s a nice and simple outline. Bill Gates liked it so much he invested $10 million into the Big History Project in 2011 to help try it out in actual classrooms. But for understanding the growth of consciousness during the evolutionary history of life, Big History is pretty weak. A panpsychist might like the fact that 4 of the 8 phases occur before life, but as Dan Dennett said, “Electrons can’t accrue memories. They do not change over billions of years. They do not participate in the arrow of time, so there is no way for them to be said to have intentions, feelings, purposes, or goals.” I agree. To me, you need a subject to have a subjective experience. Therefore, we need a lot more detail about the 5th threshold covering the 3.6 billion years of life before Homo sapiens.
The most common way to do this is with a tree of life. There are literally hundreds of them out there, all of which were inspired by the only illustration that appeared in Darwin's On the Origin of Species in 1859.
Finally, we come to the fourth of Tinbergen’s four questions. His framework for analyzing all biological phenomena has proven to be extremely useful. The first two questions represented the two static elements of Tinbergen’s model. They tell the “contemporary” accounts of the current form of a behavior in its present condition. For consciousness, that helped me develop my hierarchy by looking at the functions of consciousness, and then I saw that this hierarchy held up well as I went through a physicalist account of the mechanisms of consciousness. The next two questions move on to the dynamic elements, or the “chronicle” accounts that explain a biological phenomenon in terms of the sequence that got it there. In the last post, I looked at ontogeny, or the development of consciousness over a (human) lifetime. Now, we can look at the ultimate tale of consciousness—its phylogenetic history.
I noted at the end of my last post about ontogeny that I wasn’t sure how well my hierarchy would continue to hold up, but it was extremely exciting to see that the biological and psychological research into human development conformed perfectly well with my hierarchy. This was a great example of consilience where multiple streams of evidence are all pointing to the same thing. Now, it’s time for one final check. But before I can go through the details of the hierarchical development of consciousness, I have to lay the groundwork with a general overview of the phylogeny of life.
General notes about phylogeny
David Christian has perhaps developed the most well-known sweeping story of existence with his groundbreaking Big History project. He divides the history of the universe into eight fundamental thresholds.
- The Big Bang kicked off the origins of all cosmology about 13.7 billion years ago.
- The first stars and galaxies appeared perhaps 100 million years later.
- Chemical elements were created inside dying stars just 1 or 2 million years after that.
- The Earth and the Solar System were created about 4.5 billion years ago.
- The first evidence of life on Earth comes about 3.8 billion years ago.
- The creation of our own species, Homo sapiens, happened about 300,000 years ago.
- The emergence of agriculture occurred about 11,000 years ago.
- Finally, the Modern era of human history covers the last three or four centuries.
That’s a nice and simple outline. Bill Gates liked it so much he invested $10 million into the Big History Project in 2011 to help try it out in actual classrooms. But for understanding the growth of consciousness during the evolutionary history of life, Big History is pretty weak. A panpsychist might like the fact that 4 of the 8 phases occur before life, but as Dan Dennett said, “Electrons can’t accrue memories. They do not change over billions of years. They do not participate in the arrow of time, so there is no way for them to be said to have intentions, feelings, purposes, or goals.” I agree. To me, you need a subject to have a subjective experience. Therefore, we need a lot more detail about the 5th threshold covering the 3.6 billion years of life before Homo sapiens.
The most common way to do this is with a tree of life. There are literally hundreds of them out there, all of which were inspired by the only illustration that appeared in Darwin's On the Origin of Species in 1859.
Many of us will know the branches of these trees by a mnemonic such as “King Phillip came over for great spaghetti.” (Or, if you are a fan of Community, “Kevin, please come over for gay sex.”) But after 1990, three domains were identified on top of all this, which necessitated a new phrase like “Do kindly place candy out for good students.” This, of course, stands for:
Domain --> Kingdom --> Phylum --> Class --> Order --> Family --> Genus --> Species
Here’s a simple phylogenetic tree showing the current three-domain system where all smaller branches can be considered kingdoms.
Domain --> Kingdom --> Phylum --> Class --> Order --> Family --> Genus --> Species
Here’s a simple phylogenetic tree showing the current three-domain system where all smaller branches can be considered kingdoms.
Note how plants, animals, and fungi are just three twigs on the far upper right of this tree. An even more humbling depiction was produced by David Mark Hillis in 2008 based on completely sequenced genomes. See his popular “Hillis Plot” depiction below, where Homo sapiens are just one twig placed two ticks before midnight. Take a moment to google a few of our closest relatives. It’s only 10 steps to brewer’s yeast!
In 2015, the first draft of the Open Tree of Life was published, in which information from nearly 500 previously published trees was combined into a single free online database. The first draft included 2.3 million species, mainly composed of bacteria.
We now know that horizontal gene transfer may mean that these trees are more of a tangled thicket than neatly branching pyramids, but the most important points still stand. All of life is related, and we all share the same building blocks. And this is important to the understanding of consciousness because of everything these building blocks do.
In neuroscientist Peter Sterling’s new book What Is Health? Allostasis and the Evolution of Human Design, Sterling details the evolutionary continuity from earlier life forms to humans. He breaks our evolutionary past into four epochs — single cell life, multicellular organisms, mammals, and humans. What’s important for him as a neuroscientist, though, is just how much went on during that first epoch. Single cell life evolved the core metabolic processes such as using ATP for energy as well as the genetic code that enables all life to share the same proteins and enzymes. A full 75% of our proteins are homologues (similar in position, structure, and origin but not necessarily in function) to those seen in prokaryotes, the first life forms.
Another neuroscientist, Seth Grant, notes that “all of the proteins that are in our synapses evolved before the brain and before multi-cellular organisms. They evolved in unicellular organisms that have lived on the planet for several billion years before the first multi-cellular animal. [T]hose proteins are controlling the behavior of unicellular organisms. They control how they adapt and respond to their environment. They are involved in how they learn responses to their environment. And this tells us then that the fundamental molecular machinery of the behavior of the human brain is actually the fundamental molecular machinery of behavior in unicellular organisms, and some of those molecules go all the way back to the last universal common ancestor, which is about 3.5 billion years ago.”
So, through a variety of methods, we have an incredibly detailed picture of the interrelated lines of descent for all of life. When did these changes happen? Well, you can look into any one species to know more about its heritage, but here is a general timeline:
We now know that horizontal gene transfer may mean that these trees are more of a tangled thicket than neatly branching pyramids, but the most important points still stand. All of life is related, and we all share the same building blocks. And this is important to the understanding of consciousness because of everything these building blocks do.
In neuroscientist Peter Sterling’s new book What Is Health? Allostasis and the Evolution of Human Design, Sterling details the evolutionary continuity from earlier life forms to humans. He breaks our evolutionary past into four epochs — single cell life, multicellular organisms, mammals, and humans. What’s important for him as a neuroscientist, though, is just how much went on during that first epoch. Single cell life evolved the core metabolic processes such as using ATP for energy as well as the genetic code that enables all life to share the same proteins and enzymes. A full 75% of our proteins are homologues (similar in position, structure, and origin but not necessarily in function) to those seen in prokaryotes, the first life forms.
Another neuroscientist, Seth Grant, notes that “all of the proteins that are in our synapses evolved before the brain and before multi-cellular organisms. They evolved in unicellular organisms that have lived on the planet for several billion years before the first multi-cellular animal. [T]hose proteins are controlling the behavior of unicellular organisms. They control how they adapt and respond to their environment. They are involved in how they learn responses to their environment. And this tells us then that the fundamental molecular machinery of the behavior of the human brain is actually the fundamental molecular machinery of behavior in unicellular organisms, and some of those molecules go all the way back to the last universal common ancestor, which is about 3.5 billion years ago.”
So, through a variety of methods, we have an incredibly detailed picture of the interrelated lines of descent for all of life. When did these changes happen? Well, you can look into any one species to know more about its heritage, but here is a general timeline:
Okay. So where is consciousness??
As Dan Dennett said, “The search for the simplest form of consciousness is a snipe hunt. Starfish have some elements of consciousness, so do trees, and bacteria. (But not electrons.) We can argue about motor proteins. The question of ‘where do you draw the line?’ is an ill-motivated question. Where do you draw the line between night and day?”
Dennett’s pithy quote echoes comments made in the Wikipedia entry for Consciousness.
“Opinions are divided as to where in biological evolution consciousness emerged and about whether or not consciousness has any survival value. Some argue that consciousness is a by-product of evolution. It has been argued that consciousness emerged (i) exclusively with the first humans, (ii) exclusively with the first mammals, (iii) independently in mammals and birds, or (iv) with the first reptiles. Other authors date the origins of consciousness to the first animals with nervous systems or early vertebrates in the Cambrian over 500 million years ago. Donald Griffin suggests in his book Animal Minds a gradual evolution of consciousness.”
Basically, and unsurprisingly, seeing the emergence of consciousness depends on your definition of consciousness. I myself believe that the amorphous concept of consciousness can best be understood as the collection of processes that enable living organisms (governed by the various laws of selection) to sense and respond to biological forces. This leads us to another of “Darwin’s strange inversions” where, rather than looking for a single set of essential criteria that tells us whether consciousness is on or off, we are much better served by considering all of the tiny incremental additions of capabilities that has led to everything we now call consciousness. In this way, I think my theory brings other definitions of consciousness together under one umbrella and it matches the biological history of life. Having a dynamic picture, in the form of a growing hierarchy, mimics the growing tree of life. And this makes thinking about consciousness much clearer. (At least it does for me.)
So, let’s look at how my hierarchy lays on top of all of this. Just as before, during the examination of the first three Tinbergen questions, there are lot of intricate details to consider. Therefore, I’ll once again write simple numbered statements in bold, followed by their justifications in bullet point format, so you can quickly read the statements to get the gist of my arguments. This allows you to dip into any of the details for each statement if you want further information. Or you can click on the links provided for even more. Since my hierarchy has proven to work well so far, I’ll continue to work within it and hope that it proves to be an effective guide to consciousness this one last time. Here goes!
1.0 Origin of Life. The first three criteria for life are: organization, growth, and reproduction.
1.1 Our best hypothesis for the initial creation of life is that it emerged from basic chemical processes alone. Our best estimate is that this occurred in the form of microbes somewhere between 3.8 and 4.4 billion years ago.
2.0 Affect. The first four cognitive abilities—response to stimuli, adaptation, homeostasis, and metabolism—enable the fulfillment of the final four criteria for life: sense perception, valence, discrimination, and motivation.
2.1 As soon as life begins (by organizing, growing, and reproducing), a subject emerges. Since physical forces act on all physical matter, these subjects will be affected. Since change is inevitable in a dynamic universe, they will face selection pressures. These forces and pressures are the initial core of subjectivity that affect life right from the very beginning.
2.2 Once life is faced with selection pressures, tiny lifespans with even minimal variability will produce incredibly vast numbers of trials and errors over millions and billions of years. This evolutionary process will produce all sorts of solutions that will, logically, result in longer and/or more stable forms of survival.
2.3 This affective core of consciousness, driven by chemistry alone, is the simplest version of the objective chemical changes we call emotions. Note that these are embodied moods, which are separate from the subjective mental feelings that some individuals later evolve to have.
2.4 In humans, we know that the earliest emotional responses differentiated into four basic drives over 300 million years ago. They keep individuals alive. Later, between 55 and 85 million years ago, they differentiated further into three more basic drives that benefit social groups.
2.5 The full history of the development of affect in living organisms is of course too long and varied to give in detail. But here are some interesting highlights from the rough timeline along the way as the final four criteria for life have developed — sense perception, valence, discrimination, and motivation.
3.0 Intention. Five more cognitive abilities—attention, memory, pattern recognition, learning, and communication—enable intentional actions of the core self, eventually including the delay of reflexes.
3.1 The five cognitive abilities that drive intention do not leave fossil records. But we know from the types of organisms that exhibit them now that they will have emerged and grown since at least the rise of complex multicellularity starting possibly 1.6 billion years ago.
4.0 Prediction. This level in the hierarchy of consciousness is enabled by mechanisms for the cognitive abilities of anticipation, problem solving, and error detection.
4.1 Once actions become intentional, they and their effects in the world can be modeled so as to improve outcomes and avoid miscues. This appears to only happen in animals with brains that have neuroplasticity and can learn from experience.
4.2 Before brains emerged, more sophisticated cognition came from the emergence of faster internal communication systems built using neurons. These first appeared, driven by predation, during the ‘Cambrian explosion’ approximately 525 million years ago.
4.3 Neurons soon bundled together into simple brains, which then developed more features, complexity, and cognitive abilities over the last 520 million years.
4.4 As you would expect from the blind trials and errors of evolution, the development of intelligent predictions is not linear. Parallel examples of the emergence of traits are numerous. An excellent example of this is found in cephalopods whose intelligence is utterly alien to us vertebrates.
5.0 Awareness. This level in the hierarchy of consciousness is enabled by mechanisms for the cognitive abilities of self-reference.
5.1 Awareness is also called reflective consciousness as it involves thinking about thoughts or feelings themselves. These models of thinking about the self may simply arise by turning predictive models of others towards the sensory input of the self.
5.2 Like all complex phenomena that evolve over time, awareness does not just “turn on” like a light bulb. There are many intermediate steps of many types of awareness that many different animals likely possess.
5.3 Trace conditioning appears to be a type of learning that requires conscious awareness. We know this from the self-report of humans who do or do not learn during trace conditioning trials. But we see that some animals are also capable of trace conditioning. This is a strong indicator of awareness in non-human animals.
5.4 The most well-known test for conscious awareness is the mirror self-recognition test. Several non-human animal species appear to pass this test, including mammals, birds, and fish. This would indicate that awareness may have arisen as long ago as early vertebrates (which, as noted above, first appeared approximately 525 million years ago during the Cambrian explosion).
5.5 Awareness may have evolved independently in cephalopods too, which would mean it may be very widespread in the animal kingdom.
6.0 Abstraction. This level in the hierarchy of consciousness is enabled by mechanisms for understanding and creating symbols, art, language, memes, writing, mathematics, philosophy, and science, which all act to expand culture.
6.1 Language is the vital element for abstract consciousness. It is the ability to evoke something that isn’t present in the senses by the use of another sound or movement. Its evolutionary origins are unknown and said to be one of the hardest problems in science. It may have originated in humans somewhere between 2.3 and 6 million years ago.
6.2 A host of abstractions emerged as Homo sapiens developed. Language, art, and storytelling all appeared from 260,000 to 350,000 years ago. More advanced abstractions and technologies have emerged steadily since then.
As Dan Dennett said, “The search for the simplest form of consciousness is a snipe hunt. Starfish have some elements of consciousness, so do trees, and bacteria. (But not electrons.) We can argue about motor proteins. The question of ‘where do you draw the line?’ is an ill-motivated question. Where do you draw the line between night and day?”
Dennett’s pithy quote echoes comments made in the Wikipedia entry for Consciousness.
“Opinions are divided as to where in biological evolution consciousness emerged and about whether or not consciousness has any survival value. Some argue that consciousness is a by-product of evolution. It has been argued that consciousness emerged (i) exclusively with the first humans, (ii) exclusively with the first mammals, (iii) independently in mammals and birds, or (iv) with the first reptiles. Other authors date the origins of consciousness to the first animals with nervous systems or early vertebrates in the Cambrian over 500 million years ago. Donald Griffin suggests in his book Animal Minds a gradual evolution of consciousness.”
Basically, and unsurprisingly, seeing the emergence of consciousness depends on your definition of consciousness. I myself believe that the amorphous concept of consciousness can best be understood as the collection of processes that enable living organisms (governed by the various laws of selection) to sense and respond to biological forces. This leads us to another of “Darwin’s strange inversions” where, rather than looking for a single set of essential criteria that tells us whether consciousness is on or off, we are much better served by considering all of the tiny incremental additions of capabilities that has led to everything we now call consciousness. In this way, I think my theory brings other definitions of consciousness together under one umbrella and it matches the biological history of life. Having a dynamic picture, in the form of a growing hierarchy, mimics the growing tree of life. And this makes thinking about consciousness much clearer. (At least it does for me.)
So, let’s look at how my hierarchy lays on top of all of this. Just as before, during the examination of the first three Tinbergen questions, there are lot of intricate details to consider. Therefore, I’ll once again write simple numbered statements in bold, followed by their justifications in bullet point format, so you can quickly read the statements to get the gist of my arguments. This allows you to dip into any of the details for each statement if you want further information. Or you can click on the links provided for even more. Since my hierarchy has proven to work well so far, I’ll continue to work within it and hope that it proves to be an effective guide to consciousness this one last time. Here goes!
1.0 Origin of Life. The first three criteria for life are: organization, growth, and reproduction.
1.1 Our best hypothesis for the initial creation of life is that it emerged from basic chemical processes alone. Our best estimate is that this occurred in the form of microbes somewhere between 3.8 and 4.4 billion years ago.
- Just like RNA, early nucleotides could both store information and function as enzymes. Early polymer enzymes would: enhance replication, use high energy molecules in the environment (near thermal vents) to recharge monomers, synthesize lipids from other molecules in the environment, and modify your lipids so they don’t leave your membrane. And that’s it. A simple 2-component system that spontaneously forms in the pre-biotic environment can eat, grow, contain information, replicate, and evolve, simply through thermodynamic, mechanical, and electrical forces. No ridiculous improbability, no supernatural forces, no lightening striking a mud puddle. Just chemistry. (Abiogenesis)
- The earliest known life forms on Earth are putative fossilized microorganisms found in hydrothermal vent precipitates. The earliest time that life forms first appeared on Earth is at least 3.77 billion years ago, possibly as early as 4.28 billion years, or even 4.5 billion years — not long after the oceans formed 4.41 billion years ago, and after the formation of the Earth 4.54 billion years ago. (Earliest Known Life Forms)
2.0 Affect. The first four cognitive abilities—response to stimuli, adaptation, homeostasis, and metabolism—enable the fulfillment of the final four criteria for life: sense perception, valence, discrimination, and motivation.
2.1 As soon as life begins (by organizing, growing, and reproducing), a subject emerges. Since physical forces act on all physical matter, these subjects will be affected. Since change is inevitable in a dynamic universe, they will face selection pressures. These forces and pressures are the initial core of subjectivity that affect life right from the very beginning.
- How far back in evolution does the ability to detect and respond to danger go? Other nonhuman animals do this. Even bees. But it’s much older still. Protozoa like paramecia or amoeba do it. Even bacteria do. In fact, it goes all the way back to the beginning of life. (Post 12)
- Higher cortical regions add much to consciousness. Of course they do. But the evolutionary “roots” of consciousness are to be found elsewhere, and they are probably affective. (Solms and Panksepp)
2.2 Once life is faced with selection pressures, tiny lifespans with even minimal variability will produce incredibly vast numbers of trials and errors over millions and billions of years. This evolutionary process will produce all sorts of solutions that will, logically, result in longer and/or more stable forms of survival.
- It's not just detecting danger either — incorporating nutrients, balancing fluids and ions, thermoregulation, reproduction for the species to survive — all of these behaviors exist in animals, but also in single-cell microbes. Value / valence / affect has been present since the beginning of life. (Post 12)
- Organisms evolve digestive vs. respiratory vs. thermoregulatory vs. immune systems. Each such specialized system is governed by a homeostatic imperative of its own. Metabolic energy balance, oxygenation, hydration, and thermoregulation (for example) are not the same things, although each of them contributes to the overall imperative of organism-wide [optimization]. (Solms)
2.3 This affective core of consciousness, driven by chemistry alone, is the simplest version of the objective chemical changes we call emotions. Note that these are embodied moods, which are separate from the subjective mental feelings that some individuals later evolve to have.
- I like Damasio's distinctions between emotions, feelings, and valences. This fits very well with my own system for mapping cognitive appraisals (i.e. judging if something is good, bad, or unknown, aka valanced) onto different events in the past, present, or future, in order to generate the things we typically call emotions (but which Damasio would distinguish as feelings). I can certainly get behind his distinction here. I could also adopt his labelling. I think he's got “the strange order of things” right by saying the chemical emotional responses would have come first before the feelings in our self became able to identify them. (Post 10)
2.4 In humans, we know that the earliest emotional responses differentiated into four basic drives over 300 million years ago. They keep individuals alive. Later, between 55 and 85 million years ago, they differentiated further into three more basic drives that benefit social groups.
- Evolutionary neuroscientist Jaak Panksepp of Bowling Green State University has identified seven emotional systems in humans that originated deeper in our evolutionary past than the Pleistocene era (over 2.5 million years ago). The emotional systems that Panskepp terms CARE (tenderness for others), PANIC (from loneliness), and PLAY (social joy) date back to early primate evolutionary history (55-85 million years ago), whereas the systems of FEAR, RAGE, SEEKING, and LUST, which govern survival instincts for the individual, have even earlier, premammalian origins (older than 300 million years ago). (Gibney)(Panksepp)
2.5 The full history of the development of affect in living organisms is of course too long and varied to give in detail. But here are some interesting highlights from the rough timeline along the way as the final four criteria for life have developed — sense perception, valence, discrimination, and motivation.
- The emergence of nervous systems has been linked to the evolution of voltage-gated sodium (Nav) channels. The Nav channels allow for communication between cells over long distances through the propagation of action potentials, whereas voltage-gated calcium (Cav) channels allow for unmodulated intercellular signaling. It has been hypothesized that Nav channels differentiated from Cav channels either at the emergence of nervous systems or before the emergence of multicellular organisms, although the origin of Nav channels in history remains unknown. (Nervous System)
- A voltage-gated sodium channel is present in members of the choanoflagellates, thought to be the closest living, unicellular relative of animals. This suggests that an ancestral form of the animal channel was among the many proteins that play central roles in animal life, but which are thought to have evolved before multicellularity. (Sodium Channel)
- Multicellularity has evolved independently at least 25 times in eukaryotes, and also in some prokaryotes. The first evidence of multicellularity is from cyanobacteria-like organisms that lived 3–3.5 billion years ago. (Multicellular organism)
- Sponges were first to branch off the evolutionary tree from the common ancestor of all animals (roughly 580 to 750 million years ago), making them the sister group of all other animals. Sponges have no cells connected to each other by synaptic junctions, that is, no neurons, and therefore no nervous system. Unlike other animals, they lack true tissues and organs. Sponges do not have nervous, digestive, or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponge cells have the ability to communicate with each other via calcium signaling or by other means. Sponge larvae differentiate sensory cells which respond to stimuli including light, gravity, and water movement, all of which increase the fitness of the organism. (Sponge)
- The nerve net is the simplest form of a nervous system found in multicellular organisms. Unlike central nervous systems, where neurons are typically grouped together, neurons found in nerve nets are spread apart. This nervous system allows cnidarians to respond to physical contact. They can detect food and other chemicals in a rudimentary way. While the nerve net allows the organism to respond to its environment, it does not serve as a means by which the organism can detect the source of the stimulus. For this reason, simple animals with nerve nets, such as Hydra, will typically produce the same motor output in response to contact with a stimulus regardless of the point of contact. (Nervous System)
- Nerve nets are found in species in the phyla Cnidaria (e.g. scyphozoa, box jellyfish, and sea anemones), Ctenophora, and Echinodermata. Cnidaria and Ctenophora both exhibit radial symmetry and are collectively known as coelenterates. Coelenterates diverged 570 million years ago, prior to the Cambrian explosion, and they are the first two phyla to possess nervous systems which differentiate during development and communicate by synaptic conduction. The nervous systems of coelenterates allow for sensation, contraction, locomotion, and hunting/feeding behaviors. (Nervous System)
- The vast majority of existing animals are bilaterians, meaning animals with left and right sides that are approximate mirror images of each other. All bilateria are thought to have descended from a common wormlike ancestor that appeared in the Ediacaran period, 550–600 million years ago. The fundamental bilaterian body form is a tube with a hollow gut cavity running from mouth to anus, and a nerve cord with an enlargement (a “ganglion”) for each body segment, with an especially large ganglion at the front, called the “brain”. (Nervous System)
- Neo-Piagetian stages have been applied to the maximum stage attained by various animals. For example, spiders (an order of arthropods) attain the circular sensory motor stage, coordinating actions and perceptions. (Piaget)
- The evolutionary ancestry of arthropods dates back to the Cambrian period. Small arthropods with bivalve-like shells have been found in Early Cambrian fossil beds dating 541 to 539 million years ago. (Arthropod)
- Vertebrates originated about 525 million years ago during the Cambrian explosion, which saw a rise in organism diversity. (Vertebrate)
- When we look at all of the proteins in mammals or vertebrate species, we find that there are a lot more of them than we find in invertebrate species. So, how could that be? It turned out that the genomes of some animal that is the ancestor of all vertebrates underwent an entire genome duplication event that was the biggest mutation of them all. It inherited an extra copy of its entire genome. And one of its descendants after that did the same thing all over again so that this animal had four copies more than the invertebrate ancestor. And it is that organism that gave rise to all of the vertebrate species on the planet. And that’s why vertebrates have much more complex genomes because they’ve had these genome duplication events. They have more genes in all their families. And as a result of that, you have more synapse proteins, which give the animals a more complex behavioral repertoire. (Seth Grant)
3.0 Intention. Five more cognitive abilities—attention, memory, pattern recognition, learning, and communication—enable intentional actions of the core self, eventually including the delay of reflexes.
3.1 The five cognitive abilities that drive intention do not leave fossil records. But we know from the types of organisms that exhibit them now that they will have emerged and grown since at least the rise of complex multicellularity starting possibly 1.6 billion years ago.
- It's not just detecting danger either — incorporating nutrients, balancing fluids and ions, thermoregulation, reproduction for the species to survive — all of these behaviors exist in animals, but also in single-cell microbes. So, behavior and even learning and memory do not require nervous systems. (Post 12)
- Chemical building blocks provide the ability to process information, which enables the repeatable decisions (cognition) necessary to remain alive. (Post 20)
- A candidate mechanism that may serve as the biological basis of the continuum of cognitive function [is] the chemistry of protein networks, whose potential information-processing power and similarity to neural networks in single cells was first described by Cambridge zoologist Dennis Bray, who noticed that “many proteins in living cells appear to have as their primary function the transfer and processing of information, rather than the chemical transformation of metabolic intermediates or the building of cellular structure.” (Lyon)
- Plant cognition is a field of research directed at experimentally testing the cognitive abilities of plants, including perception, learning processes, memory, and consciousness. Although they lack a brain and the function of a conscious working nervous system, plants are still somehow capable of being able to adapt to their environment and change the integration pathway that would ultimately lead to how a plant “decides” to take response to a presented stimulus. (Plant Cognition)
- A plant known as the Mimosa pudica was tested for the ability to adapt to closing its leaves upon repeated drops with no apparent harm appointed to the plant. The results showed that with repeated drops, the Mimosa pudica eventually stopped closing its leaves or opened its leaves quicker. This behavior exhibited a trait in which the plant has adapted to not closing, or showing minimal closing, when repeated exposure to a non-harming situation is coupled with its own defense behavior. (Plant Cognition)
- Complex multicellular organisms evolved only in six eukaryotic groups: red algae, green algae, fungi, animals, land plants, and brown algae. (Multicellular organism)
- Red algae appeared perhaps 1.6 billion years ago. (Red algae)
- Green algae appeared between 1.6 and 1 billion years ago. (Green algae)
- Fungi appeared perhaps 1 billion years ago. (Fungi)
- Animals appeared between 1 billion and 600 million years ago. (Animal)
- Land plants appeared perhaps 500 million years ago. (Land plants)
- Brown algae appeared between 200 and 150 million years ago. (Brown algae)
- Attention comes in very early in evolution, and over time it becomes more and more complex. There’s central attention, sensory attention, more cognitive kinds of attention, and they emerge gradually over this sweep of history from about half a billion years ago up to the present. (Post 13)
4.0 Prediction. This level in the hierarchy of consciousness is enabled by mechanisms for the cognitive abilities of anticipation, problem solving, and error detection.
4.1 Once actions become intentional, they and their effects in the world can be modeled so as to improve outcomes and avoid miscues. This appears to only happen in animals with brains that have neuroplasticity and can learn from experience.
- A neuron is called “identified” if it has properties that distinguish it from every other neuron in the same animal and if every individual organism belonging to the same species has one and only one neuron with the same set of properties. In vertebrate nervous systems, very few neurons are “identified” in this sense—in humans, there are believed to be none—but in simpler nervous systems, some or all neurons may be thus unique. In the roundworm C. elegans, whose nervous system is the most thoroughly described of any animal's, every neuron in the body is uniquely identifiable. One notable consequence of this fact is that the form of the C. elegans nervous system is completely specified by the genome, with no experience-dependent plasticity. (Nervous Systems)
- Animals encounter so many unpredictable challenges under natural conditions that it would be very difficult if not impossible for any combination of genetic instructions and individual experience to specify in advance the entire set of actions that are appropriate. But thinking about alternative actions and selecting one believed to be best is an efficient way to cope with unexpected dangers and opportunities. In theory such versatility might result from nonconscious information processing in the brain. But conscious thinking may well be the most efficient way for a central nervous system to weigh different possibilities and evaluate their relative advantages. (Griffin)
- Cues are enough to stimulate the behavior independent of the presence of the stimuli themselves. The representation alone is enough to guide the behavior. That capacity exists in invertebrates, and on into all vertebrates, e.g. fish and reptiles. When you get to mammals, you have a much more complex form of cognitive representation, where it begins to look deliberative, i.e. the ability to form mental models that can be predictive of things not existing. It’s a much more complicated thing than having a static memory of what was there. (Post 12)
4.2 Before brains emerged, more sophisticated cognition came from the emergence of faster internal communication systems built using neurons. These first appeared, driven by predation, during the ‘Cambrian explosion’ approximately 525 million years ago.
- Trails left by the early grazers were straight and simple, but they became more circuitous in later times (550–540 million years ago), and finally showed signs of digging into the substratum by the beginning of the ‘Cambrian explosion’ of fossils (~540 million years ago). These trails disappeared by 525 million years ago and were replaced by animals with hard coverings shaped into a wide variety of spikes, shells, and plates. The rich array of external armor and weapons in the fossil record strongly suggests that animals started to prey upon each other. The larger size of these animals put a premium on keeping different parts of the body coordinated, and their predatory behavior favored animals capable of making quick movements to obtain food, and to avoid becoming someone else’s food. Both demands favored the evolution of a fast-conducting system like neurons. The first clear indication of nervous tissue was the appearance of well-formed eyes and faint outlines of nervous systems in fossils from ~525 million years ago. (Evolution of neurons)
- Isomorphic maps are the cornerstone of image-based sensory consciousness. These maps evolved in early vertebrates more than 520 million years ago, and this process was the natural result of the extraordinary innovations of the camera eye, neural crest, and placodes. (Post 11)
4.3 Neurons soon bundled together into simple brains, which then developed more features, complexity, and cognitive abilities over the last 520 million years.
- A central, brain-like structure was present in the ancestors of the vertebrates. These primitive, fish-like creatures probably resembled the living lancelet, a jawless filter-feeder. The brain of the lancelet barely stands out from the rest of the spinal cord, but specialized regions are apparent: the hindbrain controls its swimming movements, for instance, while the forebrain is involved in vision. (A brief history of the brain)
- As early fish struggled to find food and mates, and dodge predators, many of the core structures still found in our brains evolved: the optic tectum, involved in tracking moving objects with the eyes; the amygdala, which helps us to respond to fearful situations; parts of the limbic system, which gives us our feelings of reward and helps to lay down memories; and the basal ganglia, which control patterns of movements. (A brief history of the brain)
- By 360 million years ago, our ancestors had colonized the land, eventually giving rise to the first mammals about 200 million years ago. These creatures already had a small neocortex – extra layers of neural tissue on the surface of the brain responsible for the complexity and flexibility of mammalian behaviour. (A brief history of the brain)
- The first big increases in brain size were in the olfactory bulb, suggesting mammals came to rely heavily on their noses to sniff out food. There were also big increases in the regions of the neocortex that map tactile sensations – probably the ruffling of hair in particular – which suggests the sense of touch was vital too. (A brief history of the brain)
- Why did we become social? It started when we became warm blooded. Warm blooded creatures need about 10 times more nutrition though. One way to compensate for this requirement was for mammals to develop a new structure in the brain—a cortex—which allowed them to store a tremendous amount of information in the brain and to integrate it. The cortex relied on the subcortical parts of the brain for motivations, sleep/wake patterns, etc., but the cortex allowed for a kind of predictive prowess that had not been seen on the planet before. (Post 8)
- Traditionally, scientists believed that the first true warm-blooded animals were mammal ancestors that appeared around 270 million years ago. … The discovery of [a] special kind of bone in Ophiacodon fossils is evidence that it could also grow rapidly, which in turn means that it probably had an endothermic metabolism to sustain this growth spurt. Ophiacodon lived 300 million years ago, during the Carboniferous period. That was at least 30 million years before the appearance of the first true known mammals, indicating that the furry creatures did not invent warm-bloodedness but rather inherited it from their more reptile-like forefathers. (Lacerda)
- After the dinosaurs were wiped out, about 65 million years ago, some of the mammals that survived took to the trees – the ancestors of the primates. Good eyesight helped them chase insects around trees, which led to an expansion of the visual part of the neocortex. (A brief history of the brain)
- Mastering the social niceties of group living requires a lot of brain power. Robin Dunbar at the University of Oxford thinks this might explain the enormous expansion of the frontal regions of the primate neocortex, particularly in the apes. … Besides increasing in size, these frontal regions also became better connected, both within themselves, and to other parts of the brain that deal with sensory input and motor control. (A brief history of the brain)
- Our conclusion for the moment is, this, that chimpanzees understand others in terms of a perception-goal psychology, as opposed to a full-fledged, human-like belief-desire psychology. (Call and Tomasello)
- All of [this brain development] equipped the later primates with an extraordinary ability to integrate and process the information reaching their bodies, and then control their actions based on this kind of deliberative reasoning. Besides increasing their overall intelligence, this eventually leads to some kind of abstract thought: the more the brain processes incoming information, the more it starts to identify and search for overarching patterns that are a step away from the concrete, physical objects in front of the eyes. Which brings us neatly to an ape that lived about 14 million years ago in Africa. It was a very smart ape but the brains of most of its descendants – orangutans, gorillas, and chimpanzees – do not appear to have changed greatly compared with the branch of its family that led to us. (A brief history of the brain)
- Millions of years after early hominids became bipedal, they still had small brains. We can only speculate about why their brains began to grow bigger around 2.5 million years ago, but it is possible that serendipity played a part. In other primates, the “bite” muscle exerts a strong force across the whole of the skull, constraining its growth. In our forebears, this muscle was weakened by a single mutation, perhaps opening the way for the skull to expand. This mutation occurred around the same time as the first hominids with weaker jaws and bigger skulls and brains appeared. (A brief history of the brain)
- Once we got smart enough to innovate and adopt smarter lifestyles, a positive feedback effect may have kicked in, leading to further brain expansion. … The development of tools to kill and butcher animals around 2 million years ago would have been essential for the expansion of the human brain, since meat is such a rich source of nutrients. A richer diet, in turn, would have opened the door to further brain growth. Primatologist Richard Wrangham at Harvard University thinks that fire played a similar role by allowing us to get more nutrients from our food. Eating cooked food led to the shrinking of our guts, he suggests. Since gut tissue is expensive to grow and maintain, this loss would have freed up precious resources, again favoring further brain growth. (A brief history of the brain)
- Humans (species in the genus Homo) are the only animals that cook their food, and Wrangham argues Homo erectus emerged about two million years ago as a result of this unique trait. Cooking had profound evolutionary effect because it increased food efficiency, which allowed human ancestors to spend less time foraging, chewing, and digesting. H. erectus developed a smaller, more efficient digestive tract, which freed up energy to enable larger brain growth. Wrangham also argues that cooking and control of fire generally affected species development by providing warmth and helping to fend off predators, which helped human ancestors adapt to a ground-based lifestyle. Wrangham points out that humans are highly evolved for eating cooked food and cannot maintain reproductive fitness with raw food. (Catching Fire: How Cooking Made Us Human)
- The overall picture is one of a virtuous cycle involving our diet, culture, technology, social relationships, and genes. It led to the modern human brain coming into existence in Africa by about 200,000 years ago. (A brief history of the brain)
4.4 As you would expect from the blind trials and errors of evolution, the development of intelligent predictions is not linear. Parallel examples of the emergence of traits are numerous. An excellent example of this is found in cephalopods whose intelligence is utterly alien to us vertebrates.
- Other Minds is a 2016 bestseller by Peter Godfrey-Smith on the evolution and nature of consciousness. … Godfrey-Smith's premise in this book is the fact that intelligence has evolved separately in two groups of animals: in cephalopods like octopuses and cuttlefish, and in vertebrates like birds and humans. He notes that studying cephalopods is “probably the closest we will come to meeting an intelligent alien”, but that “the minds of cephalopods are the most other of all.” (Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness)
- Godfrey-Smith disagrees with an old philosophical idea that consciousness suddenly emerged from unthinking matter; it is an active relationship with the world, built up in small steps with separate capabilities for perceiving the world, taking action with muscles, remembering the simplest of events. Such capabilities, in Godfrey-Smith's view, are present in some degree even in bacteria, which detect chemicals in their environment, and in insects such as bees, which recall the locations of food sources. (Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness)
- Since most of the animals' neurons are in their partly-autonomous arms, “for an octopus, its arms are partly self – they can be directed and used to manipulate things. But from the central brain's perspective they are partly non-self too, partly agents of their own. This is as alien a mind as we could hope to encounter.” (Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness)
5.0 Awareness. This level in the hierarchy of consciousness is enabled by mechanisms for the cognitive abilities of self-reference.
5.1 Awareness is also called reflective consciousness as it involves thinking about thoughts or feelings themselves. These models of thinking about the self may simply arise by turning predictive models of others towards the sensory input of the self.
- It is important to distinguish between perceptual and reflective consciousness. The former, called “primary consciousness” by Farthing (1992), Lloyd (1989), and others, includes all sorts of awareness, whereas the latter is a subset of conscious experiences in which the content is conscious experience itself. Reflective consciousness is thinking, or experiencing feelings, about thoughts or feelings themselves, and it is often held to include self-awareness. (Griffin)
- [At first,] the external body is not a subject but an object, and it is perceived in the same register as other objects. Something has to be added to simple perception before one’s own body is differentiated from others. This level of representation (a.k.a. higher-order thought) enables the subject of consciousness to separate itself as an object from other objects. We envisage the process involving three levels of experience: (a) the subjective or phenomenal level of the anoetic self as affect, a.k.a. first-person perspective; (b) the perceptual or representational level of the noetic self as an object, no different from other objects, a.k.a. second-person perspective; (c) the conceptual or re-representational level of the autonoetic self in relation to other objects, i.e., perceived from an external perspective, a.k.a. third-person perspective. (Solms and Panksepp)
5.2 Like all complex phenomena that evolve over time, awareness does not just “turn on” like a light bulb. There are many intermediate steps of many types of awareness that many different animals likely possess.
- The very difficulty of detecting whether animals experience reflective consciousness should make us cautious about concluding that it is impossible. Most of the suggestive evidence that will be discussed in this book points toward perceptual rather than reflective consciousness. The relation between these two general categories of consciousness can be illustrated by considering a class of intermediate cases, namely, an animal's awareness of its own body—for example, the appearance of its feet or the feeling of cold as a winter wind ruffles its fur. This tends to become an intermediate category between perceptual and reflective consciousness, for an animal might be consciously aware not only of some part of its body but also of what that structure was doing. It might not only feel its teeth crunching on food but also realize that it tastes good. Or it might not only feel the ground under its feet but also recognize that it is running in order to escape from a threatening predator. Furthermore, an animal capable of perceptual consciousness must often be aware that a particular companion is eating or fleeing. This means that it is consciously aware of both the action and of who is performing it. These would all be special cases of perceptual consciousness. This leads to inquiring how likely it is that such an animal would be incapable of thinking that it, itself, was eating or fleeing. If we grant an animal perceptual consciousness of its own actions, the prohibition against conscious awareness of who is eating or fleeing becomes a somewhat strained and artificial restriction. Furthermore, a perceptually conscious animal could scarcely be unaware of its own enjoyment of eating or its fear of the predator from which it is trying desperately to escape. One could argue that perceptually conscious animals are aware of their actions but not of the thoughts and feelings that motivate them. But emotional experiences are often so vivid and intense that it seems unlikely that when an animal is conscious of its actions it could somehow be unaware of its emotions. (Griffin)
5.3 Trace conditioning appears to be a type of learning that requires conscious awareness. We know this from the self-report of humans who do or do not learn during trace conditioning trials. But we see that some animals are also capable of trace conditioning. This is a strong indicator of awareness in non-human animals.
- Robert Clark and Larry Squire published the results of a classical Pavlovian conditioning experiment in humans. Two different test conditions were employed, both using the eye-blink response to an air puff applied to the eye, but with different temporal intervals between the air puff and a preceding, predictive stimulus (a tone). In one condition, the tone remained on until the air puff was presented and both coterminated (delay conditioning). In the other, a delay (500 or 1000 ms) was used between the offset of the tone and the onset of the air puff (trace conditioning). In both conditions, experimental subjects were watching a silent movie while the stimuli were applied, and questions regarding the contents of the silent movie and test conditions were asked after test completion. In the delay conditioning task, subjects acquired a conditioned response over 6 blocks of 20 trials: as soon as the tone appeared they showed the eye-blink response before the air puff arrived. This is a classical Pavlovian response in which a shift is noted from reaction to action, also known as specific anticipatory behavior. This shift occurred whether subjects had knowledge of the temporal relationship between tone and air puff or not: both subjects who were aware of the temporal relationship—as judged by their answers to questions regarding this relationship after test completion—and subjects who were unaware of the relationship learned this experimental task. One could say that this type of conditioning occurs automatically, reflex-like, or implicitly. In contrast, the trace conditioning task required that the subjects explicitly knew or realized the temporal relationship between the tone and air puff. Only those subjects knowing this relationship explicitly—as judged by their answers to questions regarding this relationship—succeeded in performing the task; those that were not, failed. In other words, subjects had to be explicitly aware or have conscious knowledge of the task at hand in order to bring the shift about, that is, to respond after the tone and before the air puff. This is called explicit or declarative knowledge. Interestingly, amnesia patients could perform the delay conditioning task, but not the trace conditioning task. These patients suffer from damage to the hippocampal formation or medial temporal lobe, suggesting that such an intact structure is a necessary condition for trace but not for delay conditioning to occur. Now what do animals do in this task? Interestingly, the same difference in task procedure and effects of hippocampal lesion is found in, for instance, rabbits: intact rabbits acquire both tasks, hippocampal lesioned rabbits only the delay conditioning task (Clark & Squire, 1998; Wallenstein et al., 1998). So, this would suggest that rabbits—like humans—are aware of the temporal relationship between the stimuli or have conscious knowledge of this temporal relationship and act on this. In other words, it would seem that a classical Pavlovian task might reveal aspects of awareness or consciousness in animals and “raise[s] the intriguing possibility that delay and trace conditioning could be used to study aspects of awareness in nonhuman animals.” (van den Bos)
5.4 The most well-known test for conscious awareness is the mirror self-recognition test. Several non-human animal species appear to pass this test, including mammals, birds, and fish. This would indicate that awareness may have arisen as long ago as early vertebrates (which, as noted above, first appeared approximately 525 million years ago during the Cambrian explosion).
- The Mirror Self-Recognition test is the traditional method for attempting to measure self-awareness. However, agreement has been reached that animals can be self-aware in ways not measured by the mirror test, such as distinguishing between their own and others' songs and scents. … Very few species have passed the MSR test. Species that have include the great apes (including humans), a single Asiatic elephant, dolphins, orcas, the Eurasian magpie, and the cleaner wrasse. A wide range of species has been reported to fail the test, including several species of monkeys, giant pandas, and sea lions. (Mirror Test)
- Until the 2008 study on magpies, self-recognition was thought to reside in the neocortex area of the brain. However, this brain region is absent in nonmammals. Self-recognition may be a case of convergent evolution, where similar evolutionary pressures result in similar behaviors or traits, although species arrive at them by different routes, and the underlying mechanism may be different. (Mirror Test)
5.5 Awareness may have evolved independently in cephalopods too, which would mean it may be very widespread in the animal kingdom.
- Godfrey-Smith follows the neuroscientist Stanislas Dehaene in suggesting that “there's a particular style of processing—one that we use to deal especially with time, sequences, and novelty—that brings with it conscious awareness, while a lot of other quite complex activities do not.” The ability of octopuses to learn new skills, of the kind that may demand consciousness, indicates the possibility of “an awareness that in some ways resembles our own.” (Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness)
6.0 Abstraction. This level in the hierarchy of consciousness is enabled by mechanisms for understanding and creating symbols, art, language, memes, writing, mathematics, philosophy, and science, which all act to expand culture.
6.1 Language is the vital element for abstract consciousness. It is the ability to evoke something that isn’t present in the senses by the use of another sound or movement. Its evolutionary origins are unknown and said to be one of the hardest problems in science. It may have originated in humans somewhere between 2.3 and 6 million years ago.
- “I cannot doubt that language owes its origin to the imitation and modification, aided by signs and gestures, of various natural sounds, the voices of other animals, and man's own instinctive cries.” — Charles Darwin, 1871. The Descent of Man, and Selection in Relation to Sex (Origin of Language)
- Today, there are various hypotheses about how, why, when, and where language might have emerged. Despite this, there is scarcely more agreement today than a hundred years ago, when Charles Darwin's theory of evolution by natural selection provoked a rash of armchair speculation on the topic. Since the early 1990s, however, a number of linguists, archaeologists, psychologists, anthropologists, and others have attempted to address with new methods what some consider one of the hardest problems in science. (Origin of Language)
- How [do we] get from blind genetic evolution to Bach? The first step is synanthropic words. Synanthropic means things that thrive along with humans (e.g. seagulls, cockroaches, etc.). Nobody owned the first words; they were just habits that developed. [E.g. screeching for certain predators or specific dangers.] Next are domesticated words. Domesticated means the reproduction is controlled. For words, this means conscious choosing of one over the other. This leads to differential replication. Meanings or pronunciations can change over time, but the best ones survive, usually without even noticing why. The next step are coined words, deliberately designed, although their survival is still down to selection. Then there are technical terms, which are very carefully designed, and curated under strong group pressure. E.g. phenotype vs. genotype. These are hyper-domesticated words. (Post 6)
- The time range for the evolution of language and /or its anatomical prerequisites extends, at least in principle, from the phylogenetic divergence of Homo (2.3 to 2.4 million years ago) from Pan (5 to 6 million years ago) to the emergence of full behavioral modernity some 50,000–150,000 years ago. Few dispute that Australopithecus probably lacked vocal communication significantly more sophisticated than that of great apes in general, but scholarly opinions vary as to the developments since the appearance of Homo some 2.5 million years ago. Some scholars assume the development of primitive language-like systems (proto-language) as early as Homo habilis, while others place the development of symbolic communication only with Homo erectus (1.8 million years ago) or with Homo heidelbergensis (0.6 million years ago) and the development of language proper with Homo sapiens, currently estimated at less than 200,000 years ago. (Origin of Language)
- Once early humans started speaking, there would be strong selection for mutations that improved this ability, such as the famous FOXP2 gene, which enables the basal ganglia and the cerebellum to lay down the complex motor memories necessary for complex speech. (A brief history of the brain)
6.2 A host of abstractions emerged as Homo sapiens developed. Language, art, and storytelling all appeared from 260,000 to 350,000 years ago. More advanced abstractions and technologies have emerged steadily since then.
- Bones of primitive Homo sapiens first appear 300,000 years ago in Africa, with brains as large or larger than ours. They’re followed by anatomically modern Homo sapiens at least 200,000 years ago, and brain shape became essentially modern by at least 100,000 years ago. (Longrich)
- Starting about 65,000 to 50,000 years ago, more advanced technology started appearing: complex projectile weapons such as bows and spear-throwers, fishhooks, ceramics, sewing needles. People made representational art—cave paintings of horses, ivory goddesses, lion-headed idols, showing artistic flair and imagination. A bird-bone flute hints at music. Meanwhile, arrival of humans in Australia 65,000 years ago shows we’d mastered seafaring. This sudden flourishing of technology is called the “great leap forward,” supposedly reflecting the evolution of a fully modern human brain. (Longrich)
6.3 The study of language abilities in nonhuman animals is now a fast-growing field. Many examples have recently become available which show that simple forms of language are present in nonhuman animals, meaning the origins of abstract thinking may stretch back much further in time than originally thought.
6.4 Spoken languages among animals are therefore a difference of degree rather than kind. Written language, however, appears to be a uniquely human phenomenon. This capability in humans first emerged less than 6,000 years ago and would appear to be the technology that is most responsible for our cultural evolution accelerating to the point that humans now dominate the planet.
6.5 This completes the final Evolutionary Epistemological Mechanisms (EEMs) from Donald Campbell, which have been slowly accruing during this evolutionary history.
Brief comments to close
This may have been the hardest of the 4 Tinbergen questions to answer. Our scientific explorations into this realm have left us with vast ranges for when different cognitive abilities may have emerged and slowly grown. But summarizing the findings above, and focusing simply on the emergence of each level, we find this final chart for my hierarchies of consciousness:
- The gestural theory states that human language developed from gestures that were used for simple communication. Research has found strong support for the idea that verbal language and sign language depend on similar neural structures. Nonhuman primates can use gestures or symbols for at least primitive communication, and some of their gestures resemble those of humans, such as the “begging posture”, with the hands stretched out, which humans share with chimpanzees. (Origin of Language)
- In the wild, the communication of vervet monkeys has been the most extensively studied. They are known to make up to ten different vocalizations. Many of these are used to warn other members of the group about approaching predators. They include a “leopard call”, a “snake call”, and an “eagle call”. Each call triggers a different defensive strategy in the monkeys who hear the call and scientists were able to elicit predictable responses from the monkeys using loudspeakers and prerecorded sounds. (Origin of Language)
- In experiments on 100 study participants across age groups, cultures, and species, researchers found that indigenous Tsimane' people in Bolivia's Amazon rainforest, American adults and preschoolers, and macaque monkeys all show, to varying degrees, a knack for “recursion”, a cognitive process of arranging words, phrases or symbols in a way that helps convey complex commands, sentiments, and ideas. The findings, published today (26 June 2020) in the journal Science Advances, shed new light on our understanding of the evolution of language, researchers said. (Anwar)
- In an online event with Eva Meijer about her book When Animals Speak, Meijer discussed studies that show dolphins and bats use names for each other and chickens even create names for the people they regularly interact with.
- Jays and crows choose particular gifts they believe will appeal to their partners, and so have a “theory of mind” — they can see things from another’s point of view. Prairie dogs use chattering calls to describe different intruders — not only a human, but how large he or she is, the color of their clothes, and whether they are carrying an umbrella or a gun. Many mammals can learn human words, produce new sounds, or acquire other languages: orcas, for example, can imitate the cries of dolphins. (Meijer)
- Neo-Piagetian stages have been applied to the maximum stage attained by various animals. For example, … pigeons attain the sensory motor stage, forming concepts. (Piaget)
- Birds are descendants of the primitive avialans which first appeared about 160 million years ago in China. (Bird)
6.4 Spoken languages among animals are therefore a difference of degree rather than kind. Written language, however, appears to be a uniquely human phenomenon. This capability in humans first emerged less than 6,000 years ago and would appear to be the technology that is most responsible for our cultural evolution accelerating to the point that humans now dominate the planet.
- Cuneiform is an ancient writing system that was first used in around 3400 BC. Distinguished by its wedge-shaped marks on clay tablets, cuneiform script is the oldest form of writing in the world. (Origin of Language)
- The MacCready Explosion: 10,000 years ago, human population plus livestock and pets were approximately 0.1% of terrestrial vertebrate biomass. Today, it is 98%. This is probably the biggest, fastest, biological change on the planet ever. Genes don’t explain it. Technology does. (Post 6)
6.5 This completes the final Evolutionary Epistemological Mechanisms (EEMs) from Donald Campbell, which have been slowly accruing during this evolutionary history.
- Campbell settled on a 10-step outline that showed the broad categories of mechanisms that biological life has used to gain knowledge. This starts with the earliest origins of life where problems were solved over generations through mere genetic variance alone, without any aids from motion or the formation of memories. This earliest slow accrual of genetic knowledge eventually led, according to Campbell, to the other mechanisms: movement, habit, instinct, visually-supported decisions, memory-supported decisions, observational learning from social interactions, language, cultural transmissions, and finally, scientific accumulations of knowledge. (Gibney)
Brief comments to close
This may have been the hardest of the 4 Tinbergen questions to answer. Our scientific explorations into this realm have left us with vast ranges for when different cognitive abilities may have emerged and slowly grown. But summarizing the findings above, and focusing simply on the emergence of each level, we find this final chart for my hierarchies of consciousness:
So, that’s just about it in this long series on consciousness. Once again, we have excellent consilience where multiple streams of evidence are all pointing to the same thing. All that is left for me now is to put together one final summary and see how my new definition and mapping of the features of consciousness might help us answer the most stubborn problems the field has previously acknowledged. I can hardly wait.
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Previous Posts in This Series:
Consciousness 1 — Introduction to the Series
Consciousness 2 — The Illusory Self and a Fundamental Mystery
Consciousness 3 — The Hard Problem
Consciousness 4 — Panpsychist Problems With Consciousness
Consciousness 5 — Is It Just An Illusion?
Consciousness 6 — Introducing an Evolutionary Perspective
Consciousness 7 — More On Evolution
Consciousness 8 — Neurophilosophy
Consciousness 9 — Global Neuronal Workspace Theory
Consciousness 10 — Mind + Self
Consciousness 11 — Neurobiological Naturalism
Consciousness 12 — The Deep History of Ourselves
Consciousness 13 — (Rethinking) The Attention Schema
Consciousness 14 — Integrated Information Theory
Consciousness 15 — What is a Theory?
Consciousness 16 — A (sorta) Brief History of Its Definitions
Consciousness 17 — From Physics to Chemistry to Biology
Consciousness 18 — Tinbergen's Four Questions
Consciousness 19 — The Functions of Consciousness
Consciousness 20 — The Mechanisms of Consciousness
Consciousness 21 — Development Over a Lifetime (Ontogeny)
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Previous Posts in This Series:
Consciousness 1 — Introduction to the Series
Consciousness 2 — The Illusory Self and a Fundamental Mystery
Consciousness 3 — The Hard Problem
Consciousness 4 — Panpsychist Problems With Consciousness
Consciousness 5 — Is It Just An Illusion?
Consciousness 6 — Introducing an Evolutionary Perspective
Consciousness 7 — More On Evolution
Consciousness 8 — Neurophilosophy
Consciousness 9 — Global Neuronal Workspace Theory
Consciousness 10 — Mind + Self
Consciousness 11 — Neurobiological Naturalism
Consciousness 12 — The Deep History of Ourselves
Consciousness 13 — (Rethinking) The Attention Schema
Consciousness 14 — Integrated Information Theory
Consciousness 15 — What is a Theory?
Consciousness 16 — A (sorta) Brief History of Its Definitions
Consciousness 17 — From Physics to Chemistry to Biology
Consciousness 18 — Tinbergen's Four Questions
Consciousness 19 — The Functions of Consciousness
Consciousness 20 — The Mechanisms of Consciousness
Consciousness 21 — Development Over a Lifetime (Ontogeny)
