Consciousness 21 — Development Over a Lifetime (Ontogeny)

Time now to tackle the third of Tinbergen’s four questions. His framework for analyzing all biological phenomena is definitely helping me shed light on the multifaceted concept of consciousness. So far, my hierarchical definition was rounded into shape by looking at the functions of consciousness, and then that hierarchy held up well as I went through a physicalist account of the mechanisms of consciousness. These two tables summarize my findings so far:

These first two questions represent the two static elements of Tinbergen’s model. They are “contemporary” accounts that explain the current form of a behavior in its present condition. The next two questions move on to the dynamic elements, or the “chronicle” accounts that explain the biological phenomenon in terms of the sequence that got it there. For example, you wouldn’t have a complete understanding of a frog without exploring both its tadpole phase as well as the evolutionary history of amphibians. The species history is known as the tale of phylogeny, which I’ll leave for last. In this post, I’ll look at the local / proximate tale of an individual, which is called ontogeny. And in particular, I’ll confine myself to the ontogeny of human consciousness, since that’s the only form of consciousness that we have first-hand experience of.Before I get to the details of that, let me give a few general notes.
 
General notes about ontogeny
 
As Dan Dennett has noted, an evolutionary view of history requires one to drop any essentialized views. There just aren’t any eternal essences in nature that suddenly turn on or off. Likewise, everything in biology has changed slowly over billions of years in tiny increments. Viewing consciousness through this lens helps you see it as a slowly growing phenomenon over the life of an individual. (We’ll get to how it has slowly grown over the development of species in the next post.) This is precisely why a hierarchical definition of consciousness is required—to mimic the evolutionary change and growth of nature.
 
In an earlier post, I said this reminded me of “the parable of the immune system” that the evolutionary scientist David Sloan Wilson likes to use. On an episode of The Psychology Podcast, Wilson said: “The human immune system is immensely modular. We inherit it, and it does not change during our lifetime. It is something that evolved by genetic evolution, but it is triggered by environmental circumstances. [This] adaptive component of the immune system is highly evolutionary. That’s the ability of antibodies to vary and for the successful antigens to be ramped up. So that’s an evolutionary process that takes place during the lifetime of the organism. The whole thing is densely modular but also amazingly open-ended. Why can’t we say the same thing about the human behavioral system?” Well, it seems obvious (to me anyway) that we can say the same thing about our behavior—that it adapts during our lifetimes to successful and unsuccessful interactions with the environment. And the same thing applies to our growing powers of consciousness—they give life more and more degrees of freedom as they help an organism make more and more sense of its environment.
 
In a recent Brain Science Podcast, the neuroscientist Seth Grant discussed how we are beginning to see neurological evidence for this kind of development of consciousness over a lifetime. He noted,
 
“We all know that humans and every other animal go through a stereotypical trajectory of lifespan behavioral changes. When a human baby is born, they have a very limited set of behavioral responses. But they very rapidly, over the course of months and years, develop an increasingly complex behavioral repertoire. They also go through phases, famously described by Piaget and others. … These lifespan trajectories have been well documented before, but the question is, why do we have them? Why do they come about? In this paper that we’ve just published, we found that there was a remarkable set of changes [in synapses] across the lifespan. The synaptome map of the brain and its architecture changes at every age throughout life. In other words, our brain is always changing. Over the first few months of the mouse, which is the equivalent of the first few decades of a human, there was a remarkable explosion of synaptic diversity. Just as the behavioral repertoire was very limited in the new-born animal, so was the synaptic diversity. This fits well with our earlier work linking the two.”
 
This neurological evidence is just beginning to come in, so I can’t say much more than this about the ontology of mechanisms for consciousness, but as Grant noted, the psychologist Jean Piaget spent a lifetime studying the behavioral development of children. He argued that intelligence develops in a series of stages that are related to age and are progressive because one stage must be accomplished before the next can occur. By the end of the 20th century, Piaget was second only to B. F. Skinner as the most cited psychologist of that era. Although his ideas were subjected to massive scrutiny, Piaget's original model “has proved to be remarkably robust.” I don’t want to pretend that there haven’t been “innumerable improvements and qualifications of his work, coming from a plethora of neo-Piagetian and post-Piagetian variants,” but for the purposes of sketching out the ontology of consciousness, Piaget proves invaluable and I’ll rely on him heavily.
 
Just as before, during the examination of the first two Tinbergen questions, there are lot of intricate details to consider. So, I’ll continue to write simple numbered statements followed by their justifications so you can quickly read the statements to get the gist of my arguments. You can dip into any of the details for each statement if you want further information. Or click on the links there for even more. I’ll also continue to work within the structure of my hierarchy since it is proving to be an effective guide to consciousness. Here goes!
 
1.0 Origin of Life. The first three criteria for life are: organization, growth, and reproduction.
 
1.1 The genetic makeup for each new human is determined at conception. Fertilization kicks off biological processes that, when successful, eventually lead to a life. The first three criteria for life are gradually met during the early stages of prenatal development.
 

• The first sperm cell to successfully penetrate the egg cell donates its genetic material (DNA) to combine with the DNA of the egg cell resulting in a new organism called the zygote. The term “conception” refers variably to either fertilization or to formation of the conceptus after its implantation in the uterus, and this terminology is controversial. (Prenatal Development)
• The first two weeks from fertilization is referred to as the germinal stage or pre-embryonic stage. The zygote spends the next few days traveling down the fallopian tube dividing several times to form a ball of cells called a morula. Further cellular division is accompanied by the formation of a small cavity between the cells. This stage is called a blastocyst. Up to this point there is no growth in the overall size of the embryo, as it is confined within a glycoprotein shell, known as the zona pellucida. Instead, each division produces successively smaller cells. (Prenatal Development)
• The blastocyst reaches the uterus at roughly the fifth day after fertilization. It is here that disintegration of the zona pellucida occurs. This process is analogous to hatching. This allows cells of the blastocyst to come into contact with, and adhere to, cells of the uterus. In most successful pregnancies, the embryo implants 8 to 10 days after ovulation. Rapid growth occurs and the embryo's main features begin to take form. This process is called differentiation, which produces the varied cell types, such as blood cells, kidney cells, and nerve cells. (Prenatal Development)

 
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 The final four criteria for life are met in the next stages of prenatal development. A viable fetus will, on its own, display the first four cognitive abilities in order to remain alive and begin to adapt to its environment.
 

• Following fertilization, the embryonic stage of development continues until the end of the 10th week. By the end of the tenth week of gestational age the embryo has acquired its basic form and is referred to as a fetus. The next period is that of fetal development where many organs become fully developed. Development continues throughout the life of the fetus and through into life after birth. Significant changes occur to many systems in the period after birth as they adapt to life outside the uterus. (Prenatal Development)
• The perinatal period is “around the time of birth.” In developed countries and at facilities where expert neonatal care is available, it is considered from 22 completed weeks of gestation (the time when birth weight is normally 500 g) to 7 completed days after birth. In many of the developing countries the starting point of this period is considered 28 completed weeks of gestation (or weight more than 1000 g). (Prenatal Development)
• While there is no sharp limit of development, gestational age, or weight at which a human fetus automatically becomes viable, a 2013 study found that “While only a small proportion of births occur before 24 completed weeks of gestation (about 1 per 1000), survival is rare and most of them are either fetal deaths or live births followed by a neonatal death.” According to studies between 2003 and 2005, 20 to 35 percent of babies born at 24 weeks of gestation survived, while 50 to 70 percent of babies born at 25 weeks, and more than 90 percent born at 26 to 27 weeks, survived. (Fetal Viability)
• One 2018 study showed that there was a significant difference between countries in what was considered to be the “grey zone”: the “grey zone” was considered to be 22.0 - 22.6/23 weeks in Sweden, 23.0 – 23.6/24 weeks in the UK, and 24.0-25.6/26 weeks in Netherlands. (Fetal Viability)
• Viability, as the word has been used in United States constitutional law since Roe v. Wade, is the potential of the fetus to survive outside the uterus after birth, natural or induced, when supported by up-to-date medicine. Fetal viability depends largely on the fetal organ maturity, and environmental conditions. (Fetal Viability)
• The United States Supreme Court stated in Roe v. Wade (1973) that viability “is usually placed at about seven months (28 weeks) but may occur earlier, even at 24 weeks.” The 28-week definition became part of the “trimester framework” marking the point at which the “compelling state interest” (under the doctrine of strict scrutiny) in preserving potential life became possibly controlling, permitting states to freely regulate and even ban abortion after the 28th week. (Fetal Viability)

 
2.2 In addition to the basic physical stimuli that a fetus responds to, language also induces changes in brain states at this early stage of life.
 

• There is evidence that the acquisition of language begins in the prenatal stage. After 26 weeks of gestation, the peripheral auditory system is already fully formed. Also, most low-frequency sounds (less than 300 Hz) can reach the fetal inner ear in the womb of mammals. Those low-frequency sounds include pitch, rhythm, and phonetic information related to language. Studies have indicated that fetuses react to and recognize differences between sounds. Such ideas are further reinforced by the fact that newborns present a preference for their mother's voice, present behavioral recognition of stories only heard during gestation, and (in monolingual mothers) present preference for their native language. A more recent study with EEG demonstrated different brain activation in newborns hearing their native language compared to when they were presented with a different language, further supporting the idea that language learning starts while in gestation. (Prenatal Development)

 
2.3 Some abilities associated with the final criteria for life are an innate part of humans, hardwired by our genetic evolution. Much behavior is plastic, however, and must be learned through experience.
 

• Fortunately, living organisms are not required to learn everything about the world from scratch. Each phenotype is endowed with innate predictions concerning biologically significant situations it is certain to encounter. Fear behaviors (freezing and fleeing), for example, are innate predictions; but each individual has to learn what to fear and what else might be done in response. What vertebrates do to meet their needs always consists in a combination of innate and learned behaviors. (Solms)
• As far as we know, all cortical functional specializations are developmental/epigenetic. The columns of cortex are initially almost identical in neuronal architecture, and the famous differences in Brodmann’s areas probably arise from use-dependent plasticity. (Solms and Panksepp)
• Much of what we have traditionally thought to be unconditioned about exteroceptive consciousness is actually learned. This has been well demonstrated by the research of Mriganka Sur, which shows that total removal of “visual” cortex in fetal mice (in utero) does not impair their adult vision at all, and redirecting visual input from occipital cortex to auditory cortex in ferrets leads to reorganization of the latter tissue to support completely competent vision. Clearly, from a corticocentric viewpoint, this either means that sensory perception is completely learned, or that perceptual functionality is completely controlled by subcortical structures, with subtle developmental extensions of affective experience perhaps being the foremost vehicle. In short, one of the great mistakes of modern cognitive neuroscience may be the assumption that cortical consciousness is built on intrinsic “hard-wired” cognitive computational principles. The resolution of conscious experiences in the neocortex may be largely learned developmental/epigenetic functions of the brain. (Solms and Panksepp)

 
2.4 The first mechanism for learning is experiencing which actions or situations lead directly to states of mind that are rewarding or punishing. This innate experience of “good” or “bad” affect drives behavior towards survival. This is the base underpinning all consciousness.
 

• Interoceptive consciousness is phenomenal; it “feels like” something. Above all, the phenomenal states of the body-as-subject are experienced affectively. Affects, rather than representing discrete external events, are experienced as positively and negatively valenced states. Their valence is determined by how changing internal conditions relate to the probability of survival and reproductive success. The empirical evidence for the feeling component are simply based on the highly replicable fact that wherever in the brain one can artificially evoke coherent emotional response patterns with deep brain stimulation, those shifting states uniformly are accompanied by “rewarding” and “punishing” states of mind. By attributing valence to experience—determining whether something is “good” or “bad” for the subject, within a biological system of values—affective consciousness (and the behaviors it gives rise to) intrinsically promotes survival and reproductive success. This is what consciousness is for. (Solms and Panksepp)

 
2.5 The first stages of childhood development explore the environment with very rudimentary behaviors and reflexes.
 

• Stage 1.1 of Piaget’s Four Stages (0–1 months): Reflex schema stage—Babies learn how the body can move and work. Vision is blurred and attention spans remain short through infancy. They are not particularly aware of objects to know they have disappeared from sight. However, babies as young as seven minutes old prefer to look at faces. The three primary achievements of this stage are: sucking, visual tracking, and hand closure. (Object Permanence)

 
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 As babies interact with the environment and further develop their cognitive capabilities, they begin to act with intentions rather than mere reflexes. They pay attention, build memories, and learn, but the classic A-not-B error shows they have not yet built prediction models in their consciousness.
 

• To start out, infants only engaged in primarily reflex actions such as sucking, but not long after, they would pick up objects and put them in their mouths. When they do this, they modify their reflex response to accommodate the external objects into reflex actions. Because the two are often in conflict, they provide the impetus for intellectual development. The constant need to balance the two triggers intellectual growth. (Piaget)
• Stage 1.2 of Piaget’s Four Stages (1–4 months): Primary circular reactions—Babies notice objects and start following their movements. They continue to look where an object was, but for only a few moments. They “discover” their eyes, arms, hands, and feet in the course of acting on objects. This stage is marked by responses to familiar images and sounds (including parents’ faces) and anticipatory responses to familiar events (such as opening the mouth for a spoon). The infant's actions become less reflexive and intentionality emerges. (Object Permanence)
• Stage 1.3 of Piaget’s Four Stages (4–8 months): Secondary circular reactions—Babies will reach for an object that is partially hidden, indicating knowledge that the whole object is still there. If an object is completely hidden, however, the baby makes no attempt to retrieve it. The infant learns to coordinate vision and comprehension. Actions are intentional, but the child tends to repeat similar actions on the same object. Novel behaviors are not yet imitated. (Object Permanence)
• Stage 1.4 of Piaget’s Four Stages (8–12 months): Coordination of secondary circular reactions—This is deemed the most important for the cognitive development of the child. At this stage the child understands causality and is goal-directed. The very earliest understanding of object permanence emerges, as the child is now able to retrieve an object when its concealment is observed. This stage is associated with the classic A-not-B error. After successfully retrieving a hidden object at one location (A), the child fails to retrieve it at a second location (B). (Object Permanence)

 
3.2 Actions gradually become more complex through the integration of more information, including the formation of memories. It is our neuroplasticity that enables each individual to learn from their particular lived experience.
 

• At first glance, it may seem that the reason we don’t remember being babies is because infants and toddlers don’t have a fully developed memory. But babies as young as six months can form both short-term memories that last for minutes, and long-term memories that last weeks, if not months. (Shinskey)
• Neural plasticity is the ability of the brain to change continuously throughout an individual's life, e.g., brain activity associated with a given function can be transferred to a different location, the proportion of grey matter can change, and synapses may strengthen or weaken over time. Neuroplasticity can be observed at multiple scales, from microscopic changes in individual neurons to larger-scale changes such as cortical remapping in response to injury. Behavior, environmental stimuli, thought, and emotions may also cause neuroplastic change through activity-dependent plasticity, which has significant implications for healthy development, learning, memory, and recovery from brain damage. (Neuroplasticity)
• Hebbian theory is a neuroscientific theory claiming that an increase in synaptic efficacy arises from a presynaptic cell's repeated and persistent stimulation of a postsynaptic cell. It is an attempt to explain synaptic plasticity, the adaptation of brain neurons during the learning process. The theory is often summarized as “Cells that fire together wire together.” (Neuroplasticity)

 
3.3 As babies begin to understand more and more about their environment, early forms of communication with them becomes possible.
 

• Joint attention refers to when two people look at and attend to the same thing; parents often use the act of pointing to prompt infants to engage in joint attention. The inclination to spontaneously reference an object in the world as of interest, via pointing, and to likewise appreciate the directed attention of another, may be the underlying motive behind all human communication. (Theory of Mind Wikipedia)

 
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 intentions exist (either one’s own or the intentions of others), they can be taken into account. To do so is to use prediction to think through what the result will be from any intentions. This requires three more cognitive capacities from Lyon’s list: anticipation, problem solving, and error detection.
 

• Infants' understanding of attention in others acts as a “critical precursor” to the development of theory of mind. Understanding attention involves understanding that seeing can be directed selectively as attention, that the looker assesses the seen object as “of interest”, and that seeing can induce beliefs. (Theory of Mind)
• In this process, the organism must stay “ahead of the wave” of the biological consequences of its choices (to use the analogy that gave Andy Clark's (2016) book its wonderful title: Surfing Uncertainty): “To deal rapidly and fluently with an uncertain and noisy world, brains like ours have become masters of prediction—surfing the waves of noisy and ambiguous sensory stimulation by, in effect, trying to stay just ahead of the place where the wave is breaking (p. xiv).” (Solms)
• The Bayesian brain is [optimized] through the encoding of better models of the world leading to better predictions. It is important to note that in this model, prediction error (mediated by the sensory affect of surprise), is a “bad” thing, biologically speaking. The more veridical the brain’s generative model of the world, the less surprise (the less salience, the less consciousness, the more automaticity), the better. Freud called this the “Nirvana principle”. [In simpler terms,] the goal of all learning is automatized mental processes, increased predictability, and reduced uncertainty or surprise. (Solms and Panksepp)

 
4.2 The ability of brains to predict the world is signaled by the full grasping of object permanence. Human babies generally reach this level of development around the age of two. From then on, they operate according to schemata, which are continually refined throughout life.
 

• Object permanence is the understanding that objects continue to exist even when they cannot be seen, heard, touched, smelled, or sensed in any way. It is one of an infant's most important accomplishments, as, without this concept, objects would have no separate, permanent existence. In Piaget's theory of cognitive development, infants develop this understanding by the end of the “sensorimotor stage”, which lasts from birth to about two years of age. (Object Permanence)
• Stage 1.5 of Piaget’s Four Stages (12–18 months): Tertiary circular reaction—The child gains means-end knowledge and is able to solve new problems. The child is now able to retrieve an object when it is hidden several times within their view but cannot locate it when it is outside their perceptual field. (Object Permanence) During this stage infants explore new possibilities of objects; they try different things to get different results. (Piaget)
• Stage 1.6 of Piaget’s Four Stages (18–24 months): Invention of new means through mental combination—The child fully understands object permanence. They will not fall for A-not-B errors. Also, a baby is able to understand the concept of items that are hidden in containers. If a toy is hidden in a matchbox then the matchbox put under a pillow and then, without the child seeing, the toy is slipped out of the matchbox and the matchbox then given to the child, the child will look under the pillow upon discovery that it is not in the matchbox. The child is able to develop a mental image, hold it in mind, and manipulate it to solve problems, including object permanence problems that are not based solely on perception. The child can now reason about where the object may be when invisible displacement occurs. (Object Permanence) [In other words, this stage involves] internalization of schemata. (Piaget)
• A Schema is a structured cluster of concepts, it can be used to represent objects, scenarios, or sequences of events or relations. The original idea was proposed by philosopher Immanuel Kant as innate structures used to help us perceive the world. A schema (pl. schemata) is the mental framework that is created as children interact with their physical and social environments. (Piaget)
• While much research has been done on infants, theory of mind develops continuously throughout childhood and into late adolescence as the synapses (neuronal connections) in the prefrontal cortex develop. Children seem to develop theory of mind skills sequentially. The first skill to develop is the ability to recognize that others have diverse desires. Children are able to recognize that others have diverse beliefs soon after. The next skill to develop is recognizing that others have access to different knowledge bases. Finally, children are able to understand that others may have false beliefs and that others are capable of hiding emotions. (Theory of Mind)

 
5.0 Awareness. This level in the hierarchy of consciousness is enabled by mechanisms for the cognitive abilities of self-reference.
 
5.1 By making cognitive connections between intentions, predictions, and internal affective feelings, the development of self-awareness slowly arises.
 

• [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. The self of everyday cognition is therefore largely an abstraction. That is why the self is so effortlessly able to think about itself in relation to objects, in such everyday situations as “I am currently experiencing myself looking at an object.” (Solms and Panksepp)
• As predictions and perceptions improve, organisms eventually make the connection that there is a self which has its own mind. Awareness is achieved. This development is covered by the final cognitive capacity from Lyon’s list: self-reference. Such conscious cognition allows memories and thoughts built from the lived past and the anticipated future to create the autonoetic, autobiographical self. (Post 19)

 
5.2 Mirror Self-Recognition tests currently act as our best marker for the attainment of this level of consciousness. Passing this test is correlated with object permanence, and similarly occurs in humans around the age of two, although there are differences in this timeline that appear to be related to rearing behaviors.
 

• 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 have been reported to fail the test, including several species of monkeys, giant pandas, and sea lions. … A strong correlation between self-concept and object permanence has been demonstrated. (Mirror Test)
• From the ages of 6 to 12 months, the child typically sees a “sociable playmate” in the mirror's reflection. Self-admiring and embarrassment usually begin at 12 months, and at 14 to 20 months, most children demonstrate avoidance behaviors. Finally, at 18 months, half of children recognize the reflection in the mirror as their own and by 20 to 24 months, self-recognition climbs to 65%. (Mirror Test)
• A 2010 cross-cultural study observed variations in the presence of self-oriented behaviors exhibited by children (ranging from 18 to 55 months old) from non-Western rural communities and Western urban and rural communities when each was given the mark test. They found that children from Western communities showed earlier signs of self-oriented behaviors toward the mark when given the mirror mark test, whereas an absence of this behavior was seen in children from non-Western communities. Such results do not suggest a delayed development in cognition in the latter group, but rather the potential of how differences in parenting styles (as influenced by culture) impact the way children express self-concept. … For example, a Cameroonian Nso sample of infants 18 to 20 months of age had an extremely low amount of self-recognition outcomes at 3.2%. The study also found two strong predictors of self-recognition: object stimulation (maternal effort of attracting the attention of the infant to an object either person touched) and mutual eye contact. (Mirror Test)

 
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 Passing through the first five levels of consciousness in this hierarchy creates a very aware living being that is rare in the animal kingdom. And yet, we don’t remember any of the steps it took to get us there.
 

• Most of us don’t have any memories from the first three to four years of our lives—in fact, we tend to remember very little of life before the age of seven. The phenomenon, known as “childhood amnesia”, has been puzzling psychologists for more than a century—and we still don’t fully understand it. (Shinskey)
• Virtually nobody has memories from very early childhood. It's clear that young children do remember facts in the moment such as who their parents are, or that one must say “please” before mom will give you candy. This is called “semantic memory.” Until sometime between the ages two and four, however, children lack “episodic memory”—memory regarding the details of a specific event. (Shouse)
• The typical boundary for the offset of childhood amnesia—three and a half years—shifts with age. Children and teenagers have earlier memories than adults do. This suggests that the problem may be less with forming memories than with maintaining them. (Shinskey)
• [There is a] theory that we can’t remember our first years simply because our brains hadn’t developed the necessary equipment. The explanation emerges from the most famous man in the history of neuroscience, known simply as patient HM. After a botched operation to cure his epilepsy damaged his hippocampus, HM was unable to recall any new events. Intriguingly, however, he was still able to learn other kinds of information—just like babies. When scientists asked him to copy a drawing of a five-pointed star by looking at it in a mirror (harder than it sounds), he improved with each round of practice—despite the fact the experience itself felt completely new to him. Perhaps, when we’re very young, the hippocampus simply isn’t developed enough to build a rich memory of an event. Baby rats, monkeys and humans all continue to add new neurons to the hippocampus for the first few years of life and we are all unable to form lasting memories as infants—and it seems that the moment we stop creating new neurons, we’re suddenly able to form long-term memories. (Gorvett)
• While the neurological explanation does account for blanks in very young children's memories, it does not give a full explanation for childhood amnesia because it fails to account for the years after the age of four. It also fails to address the issue that children themselves do not show childhood amnesia. Children around the age of two to three have been found to remember things that occurred when they were only one to two years old. This discovery that three-year-olds can retrieve memories from earlier in their life implies that all necessary neurological structures are in place to recall episodic information over the short-term, but evidently not over the long-term into adulthood. (Childhood Amnesia)

 
6.2 It may be that this lack of memory is precisely because one must pass through the first five levels of consciousness in order to begin recording an autobiographical self.
 

• The development of a cognitive self is also thought by some to have a strong effect on encoding and storing early memories. As toddlers grow, a developing sense of the self begins to emerge as they realize that they are a person with unique and defining characteristics and have individual thoughts and feelings separate from others. As they gain a sense of the self, they can begin to organize autobiographical experiences and retain memories of past events. This is also known as the development of a theory of mind which refers to a child's acceptance that they have beliefs, knowledge, and thoughts that no one else has access to. The developmental explanation asserts that young children have a good concept of semantic information but lack the retrieval processes necessary to link past and present episodic events to create an autobiographical self. Young children do not seem to have a sense of a continuous self over time until they develop awareness for themselves as an individual human being. (Childhood Amnesia)

 
6.3 The development of language is key to this ability to think about the world, to recall past events, or to imagine future possibilities. Language is an abstract representation of these things, which allows them to be repeatedly brought into the present tense of a mind, which is how memories are formed and reformed.
 

• Another factor that we know plays a role is language. From the ages of one to six, children progress from the one-word stage of speaking to becoming fluent in their native language(s), so there are major changes in their verbal ability that overlap with the childhood amnesia period. This includes using the past tense, memory-related words such as “remember” and “forget”, and personal pronouns, a favorite being “mine”. A child’s ability to verbalize about an event at the time that it happened predicts how well they remember it months or years later. One lab group conducted this work by interviewing toddlers brought to accident and emergency departments for common childhood injuries. Toddlers over 26 months, who could verbalise about the event at the time, recalled it up to five years later, whereas those under 26 months, who could not talk about it, recalled little or nothing. (Shinskey)
• On the “self-awareness being tied to language” note, I found this quote from Helen Keller interesting: “Before my teacher came to me, I did not know that I am. I lived in a world that was a no-world. I cannot hope to describe adequately that unconscious, yet conscious time of nothingness. (…) Since I had no power of thought, I did not compare one mental state with another.” (Hellen Keller, 1908: quoted by Daniel Dennett, 1991, Consciousness Explained. p 227) (Hiskey)
• If I ask you to picture a rope and climbing up it, you can do it. I specifically chose those objects and actions because it is exactly what a chimp in a zoo is familiar with. If I asked a chimp to do the same thing, could it? We don’t know, but I suspect not, because you can’t do it wordlessly. You need to be able to interact using language. Without language, I don’t think you have the cognitive systems for self-simulation and self-probing that we have. … Language allows us to be conscious of things we otherwise wouldn’t be able to be conscious of. (Dennett)

 
6.4 Language also vastly enlarges our abilities to recognize patterns in the world. This is vital for understanding and predicting events.
 

• Differences in knowledge yield striking differences in the capacity to pick up patterns. Expert chess players can instantly perceive (and subsequently recall with high accuracy) the total board position in a real game but are much worse at recall if the same chess pieces are randomly placed on the board, even though to a novice both boards are equally hard to recall. This should not surprise anyone who considers that an expert speaker of English would have much less difficulty perceiving and recalling: “The frightened cat struggled to get loose” than “Te serioghehnde t srugfcalde go tgtt ohle” which contains the same pieces, now somewhat disordered. Expert chess players, unlike novices, not only know how to Play chess; they know how to read chess—how to see the patterns at a glance. (Dennett)

 
6.5 The development of language occurs gradually over the last three of Piaget’s stages. This drastically expands the use of symbols and logic, which are the hallmarks of this sixth level of abstract consciousness.
 

• Stage 2 of Piaget’s Four Stages—Preoperational stage: starts when the child begins to learn to speak at age two and lasts up until the age of seven. During the pre-operational stage of cognitive development, Piaget noted that children do not yet understand concrete logic and cannot mentally manipulate information. Children's increase in playing and pretending takes place in this stage. However, the child still has trouble seeing things from different points of view. The Pre-operational Stage is split into two substages: the symbolic function substage, and the intuitive thought substage. (Piaget)
• Stage 2.1 of Piaget’s Four Stages—Symbolic Function Substage: from two to four years of age children find themselves using symbols to represent physical models of the world around them. Children are able to understand, represent, remember, and picture objects in their mind without having the object in front of them. Play is demonstrated by the idea of checkers being snacks, pieces of paper being plates, and a box being a table. (Piaget)
• Stage 2.2 of Piaget’s Four Stages—Intuitive Thought Substage: between about the ages of four and seven, children tend to become very curious and ask many questions, beginning the use of primitive reasoning. Children tend to propose the questions of “why?” and “how come?” This stage is when children want the knowledge of knowing everything. Piaget called it the “intuitive substage” because children realize they have a vast amount of knowledge, but they are unaware of how they acquired it. (Piaget)
• Stage 3 of Piaget’s Four Stages—Concrete operational stage: from ages seven to eleven. Children can now conserve and think logically (they understand reversibility) but are limited to what they can physically manipulate. They are no longer egocentric. During this stage, children become more aware of logic and conservation, topics previously foreign to them. Children also improve drastically with their classification skills. (Piaget)
• Stage 4 of Piaget’s Four Stages—Formal operational stage: from age eleven to sixteen and onwards. Children develop abstract thought and can easily conserve and think logically in their mind. Abstract thought is newly present during this stage of development. Children are now able to utilize metacognition. Along with this, the children in the formal operational stage display more skills oriented towards problem solving, often in multiple steps. The child is able to identify the properties of objects by the way different kinds of actions affect them. This is the process of “empirical abstraction.” By repeating this process across a wide range of objects and actions, the child establishes a new level of knowledge and insight. Once the child has constructed these new kinds of knowledge, he or she starts to use them to create still more complex objects and to carry out still more complex actions. As a result, the child starts to recognize still more complex patterns and to construct still more complex objects. (Piaget)

 
6.6 Beyond Piaget’s examination of childhood, human consciousness can continue to expand by integrating more and more information. An objectively good criterion for this expansion of consciousness would evaluate whether it created better and better models for surviving and thriving.
 

• Piaget's theory stops at the formal operational stage, but other researchers have observed the thinking of adults is more nuanced than formal operational thought. This fifth stage has been named post formal thought or operation. There are many theorists, however, who have criticized “post formal thinking,” because the concept lacks both theoretical and empirical verification. The term “integrative thinking” has been suggested for use instead. (Piaget's theory of cognitive development)
• Lawrence Kohlberg's stages of moral development constitute an adaptation of a psychological theory originally conceived by the Swiss psychologist Jean Piaget. The theory holds that moral reasoning, a necessary (but not sufficient) condition for ethical behavior, has six developmental stages, each more adequate at responding to moral dilemmas than its predecessor. Kohlberg followed the development of moral judgment far beyond the ages studied earlier by Piaget, who also claimed that logic and morality develop through constructive stages. The six stages of moral development occur in three levels. Level 1, Pre-Conventional, consists of: Stage 1—obedience and punishment orientation (How can I avoid punishment?); and Stage 2—self-interest orientation (What's in it for me?). Level 2, Conventional, consists of Stage 3—interpersonal accord and conformity (The good boy/girl attitude); and Stage 4—authority and social-order maintaining orientation (Law and order morality). Finally, level 3, Post-Conventional, consists of Stage 5—social contract orientation; and Stage 6—universal ethical principles. (Lawrence Kohlberg's stages of moral development)

 
Brief comments to close:
 
I didn’t know how this post was going to go, but it is extremely exciting to see the biological and psychological research conform perfectly to my hierarchy. It’s a great example of consilience where multiple streams of evidence are all pointing to the same thing. So, riding high, I’ll close now with my third summary chart and look forward to completing my examination of consciousness next time with the fourth of Tinbergen’s four questions. I can hardly wait for that.

--------------------------------------------
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