Hierarchical Brain

An explanation of the human brain

First published 1st February 2024. This is version 1.5 published 2nd March 2024.
Three pages are not yet published: sleep, memory and an index.
Copyright © 2024 Email info@hierarchicalbrain.com

Warning - the conclusions of this website may be disturbing for some people without a stable mental disposition or with a religious conviction.


Action is the ability of the brain to cause change or movement in the body. It is one of several high-level brain functions that make up level 6 in my hierarchical structure of levels of description because it depends on the existence of symbol schemas. I am not aware of the cause of many of my actions because I am only aware of my model of action.

An action is very often driven by a perception, by the need to validate a prediction, and the result of an action can often be a new perception. A perception is an action in reverse: a perception is an external cue that activates a symbol schema; an action is an external change caused by the activation of a symbol schema, and both involve prediction. So action and perception can be seen as the drivers of a continuous action/perception cycle.

Contents of this page
Introduction - introduction and explanation of the four categories of action.
Reflex actions - automatic reflex actions driven by very simple circuits.
Autonomous actions - actions that happen automatically and cannot be consciously controlled.
Symbol schema actions - my term for actions that are initiated by the activation of symbol schemas.
Conscious actions - symbol schema actions that require conscious attention.
Learnt subconscious actions - symbol schema actions that are learnt by conscious practice and become unconscious.
Prediction in action - the role of prediction in action and the connections to perception and attention.
My model of action - my inherent understanding of my own actions.
References - references and footnotes.


Reflex actions

Autonomous actions

Symbol schema actions

Conscious actions

Learnt subconscious actions

Prediction in action

My model of action

References For information on references, see structure of this website - references

  1. ^ The Principles of Psychology - William James 1890
    viewable here, downloadable here: Volume I and Volume II or see GoogleScholar.
    Volume 2, Chapter XIV “Instinct”, under the heading “Special human instincts”: “Mr Bain has tried, by describing the demeanor of new-born lambs, to show that locomotion is learned by a very rapid experience. But the observation recorded proves the faculty to be almost perfect from the first; and all others who have observed new-born calves, lambs, and pigs agree that in these animals the powers of standing and walking, and of interpreting the topographical significance of sights and sounds, are all but fully developed at birth. Often in animals who seem to be 'learning' to walk or fly the semblance is illusive. The awkwardness shown is not due to the fact that 'experience' has not yet been there to associate the successful movements and exclude the failures, but to the fact that the animal is beginning his attempts before the co-ordinating centres have quite ripened for their work.”
  2. ^ A unifying model for timing of walking onset in humans and other mammals - Garwicza, Christenssona and Psounib 2009
    10.1073/pnas.0905777106 downloadable here or see GoogleScholar.
    Start of abstract: “The onset of walking is a fundamental milestone in motor development of humans and other mammals, yet little is known about what factors determine its timing. Hoofed animals start walking within hours after birth, rodents and small carnivores require days or weeks, and nonhuman primates take months and humans approximately a year to achieve this locomotor skill. Here we show that a key to the explanation for these differences is that time to the onset of walking counts from conception and not from birth, indicating that mechanisms underlying motor development constitute a functional continuum from pre- to postnatal life. In a multiple-regression model encompassing 24 species representative of 11 extant orders of placental mammals that habitually walk on the ground, including humans, adult brain mass accounted for 94% of variance in time to walking onset postconception.”
  3. ^ Brain: the story of you - David Eagleman Pantheon Books 2015
    See GoogleScholar.
    Chapter 1 “Who am I”, third paragraph under the heading “Born unfinished”: “At birth we humans are helpless. We spend about a year unable to walk, about two more before we can articulate full thoughts, and many more years unable to fend for ourselves. We are totally dependent on those around us for our survival. Now compare this to many other mammals. Dolphins, for instance, are born swimming; giraffes learn to stand within hours; a baby zebra can run within forty-five minutes of birth. Across the animal kingdom, our cousins are strikingly independent soon after they’re born... the human brain is born remarkably unfinished. Instead of arriving with everything wired up - let’s call it 'hardwired' - a human brain allows itself to be shaped by the details of life experience.”
  4. ^ Fetal and neonatal thermoregulation - Asakura 2004
    downloadable here or see GoogleScholar.
    This paper contains a fascinating account of the set of actions that kicks in at the moment of birth to regulate the temperature of the new-born baby.
    Abstract, page 360:
    “...fetal temperature is maternally dependent until birth.”
  5. ^ Principles of Neural Science - Sixth edition - Kandel et al. McGraw-Hill US 2021 - or see GoogleScholar.
    In the introduction to Section V concerning movement, page 709: “The immense repertoire of motions that humans are capable of stems from the activity of some 640 skeletal muscles - all under the control of the central nervous system.”
  6. ^ Ibid. Principles of Neural Science - Sixth edition
    In the introduction to Section V concerning movement, page 709: “The task of the motor systems is the reverse of the task of the sensory systems. Sensory processing generates an internal representation in the brain of the outside world or of the state of the body. Motor processing begins with an internal representation: the desired purpose of movement. Critically, however, this internal representation needs to be continuously updated by internally generated information (efference copy) and external sensory information to maintain accuracy as the movement unfolds.”
  7. ^ Ibid. Principles of Neural Science - Sixth edition
    In the introduction to Section V concerning movement, page 710: “Motor systems are organized in a functional hierarchy, with each level concerned with a different decision. The highest and most abstract level, likely requiring the prefrontal cortex, deals with the purpose of a movement or series of motor actions. The next level, which is concerned with the formation of a motor plan, involves interactions between the posterior parietal and premotor areas of the cerebral cortex. The premotor cortex specifies the spatiotemporal characteristics of a movement based on sensory information from the posterior parietal cortex about the environment and about the position of the body in space. The lowest level of the hierarchy coordinates the spatiotemporal details of the muscle contractions needed to execute the planned movement.”
  8. ^ On Intelligence and Google Book preview - On Intelligence - Jeff Hawkins with Sandra Blakeslee, St. Martin’s Press, New York 2004
    See GoogleScholar.
    Page 46 in chapter 3 entitled “The human brain”: “The motor system of the cortex is also [like the regions dealing with sense input] hierarchically organized. ...The hierarchy of the motor area and the hierarchies of the sensory areas look remarkably similar. They seem to be put together in the same way. In the motor region we think of information flowing down the hierarchy toward M1 [the lowest motor area] to drive the muscles and in the sensory regions we think of information flowing up the hierarchy away from the senses. But in reality information flows both ways. What is referred to as feedback in sensory regions is the output of the motor region, and vice versa.”
  9. ^ The brain from inside out - Gyorgy Buzsaki 2019 Oxford University Press
    doi: 10.1093/oso/9780190905385.001.0001 or see GoogleScholar.
    Page 77, third paragraph: “These seemingly aimless movements in newborn rodents are the same as fetal movements or 'baby kicks' observed in later stages of pregnancy in humans. ... each kick helps the brain to lean about the physics of the body it controls.”
  10. ^ What are you doing? How active and observational experience shape infants’ action understanding - Hunnius and Bekkering 2014
    doi: 10.1098/rstb.2013.0490 downloadable here or see GoogleScholar.
    Abstract, page 1: “When infants execute actions, they form associations between motor acts and the sensory consequences of these acts.”
  11. ^ Livewired - David Eagleman Canongate 2020
    See GoogleScholar.
    Page 116, under the heading “Motor babbling”: “In the same way, the brain learns how to steer its body by motor babbling. Just observe that same baby in her crib. She bites her toes, slaps her forehead, tugs on her hair, bends her fingers, and so on, learning how her motor output corresponds to the sensory feedback she receives. In this way, she learns to understand the language of her body: how her outputs map onto the next inputs. By this technique, we eventually learn to walk, bring strawberries to our mouths, stay afloat in a pool, dangle on monkey bars, and master jumping jacks.”
  12. ^ Ibid. Livewired
    Page 116, under the heading “Motor babbling”: “A baby learns how to shape her mouth and her breath to produce language - not by genetics, nor by surfing Wikipedia, but instead by babbling. Sounds come out of her mouth, and her ears pick up on those sounds. Her brain can then compare how close her sound was with the utterances she’s hearing from her mother or father. Helping things along, she earns positive reactions for some utterances and not for others. In this way, the constant feedback allows her to refine her speech.”
  13. ^ Ibid. Livewired
    Bottom of page 116, under the heading “Motor babbling”: “And even better, we use the same learning method to attach extensions to our bodies. Think about riding a bicycle, a machine that our genome presumably didn’t see coming. Our brains originally shaped themselves in conditions of climbing trees, carrying food, fashioning tools, and walking great distances. But successfully riding a bicycle introduces a new set of challenges, such as carefully balancing the torso, modifying direction by moving the arms, and stopping suddenly by squeezing the hand. Despite the complexities, any seven-year-old can demonstrate that the extended body plan is easily added to ... the motor cortex.”
  14. ^ Surfing Uncertainty - Prediction, Action and the Embodied Mind - Clark 2016 Oxford University Press
    doi: 10.1093/acprof:oso/9780190217013.001.0001 see GoogleScholar.
    Bottom of page 68, in chapter 2 “Adjusting the volume”, under the heading “Gaze allocation: doing what comes naturally”: “Precision-weighted PP [Predictive Processing] accounts are ideally placed to bring all these elements together in a single unifying story: one that places neural prediction and the reduction of uncertainty centre-stage. This is because PP treats action, perception and attention as (in effect) forming a single mechanism for the context- and task-dependent combination of bottom-up sensory cues with top-down expectations.”
    Page 111, start of chapter 4 “Prediction-action machines”, under the heading “Staying ahead of the break”: “How does a guessing engine (a hierarchical prediction machine) turn prediction into action? ... by predicting the shape of its own motor trajectories. In accounting for action, we thus move from predicting the rolling present to predicting the near-future, in the form of the not-yet-actual trajectories of our own limbs and bodies. These trajectories, predictive processing suggests, are specified by their distinctive sensory (especially proprioceptive) consequences. ... predicting these (non-actual) sensory states actually serves to bring them about.”
  15. ^ Making up the mind - Frith 2007
    See GoogleScholar.
    Chapter 3 “What the brain tells us about our bodies”, pages 76-77 under the heading “Who’s Doing It?”, describes an experiment that proved that we do not necessarily even know what actions are ours. The experiment showed that if you intend to make a movement, but then it is made for you, you assume that you made it, even though you didn’t: “Daniel Wegner has proposed that we have no direct knowledge of causing our actions. All we know is that we have the intention to act, and then, a little later, the action occurs. We infer that our intention caused the action. But Wegner didn’t just stop with this speculation. He did some experiments to test the idea. He predicted that, if an action occurred after you had the intention to act, then you would assume that you had caused the act even when it was actually caused by someone else. The experiment is quite tricky in all senses of the term. When you take part in this experiment you have a companion (who is really a stooge of the experimenter). You and your companion place your right forefingers on a special mouse. By moving this mouse around you move a pointer on a computer monitor. There are lots of objects on the screen. Through earphones you hear someone name one of the objects. You think about moving the pointer toward the object. If your companion moves the pointer toward the object at that moment (he is also instructed through earphones), then you are very likely to think that you made the movement. Of course the timing is critical. If the mouse moves just before you had the thought, then you don’t feel you caused it. If the mouse moves too long afterwards, then you don’t feel you caused it either. If the interval is about 1 and 5 seconds between having the thought and the mouse moving, then you will believe you have moved your arm even when this is not actually the case.”

Page last uploaded Wed Feb 14 08:51:34 2024 MST