“Most animals begin life with all or most of their survival systems functional. Their independent life thus begins immediately or shortly after birth. Humans are a notable exception. We’re basically helpless at birth and for a long time afterwards. The principal reason is that, because our three-pound adult brain is much larger than our mother’s birth canal, we’re born with a one-pound basic brain that can traverse the canal, but can’t regulate an independent life.
During its initial 20-year post-birth development, our brain adds two pounds of mass and accompanying capabilities. This moves us from being not much more than a wet noisy pet in infancy to the functional autonomy that’s characteristic of adults. A variety of cultural systems that range from the informality of parenting to the formality of classroom instruction nurture this extended development.” (p.9)
“The principal reason that animals have a brain and plants don’t is because animals can move of their own volition and plants can’t. Rooted plants aren’t going anywhere, so they don’t even need to know where they are. What’s the point of knowing that other plants have better access to sunlight and water, or that a logger is approaching, if you can’t do anything about it?
However, if an organism has legs, wings, or fins, it needs a sensory system to provide information about here and there, a decision-making system to determine if here is better than there or there is better than here, a motor system to get it to there if that’s the better option, and a memory system to get back to here after its trip.” (p.19)
“It all begins with a typically pleasant trip of a sperm in search of an egg. Nine months later, our exit trip through our mother’s birth canal and the severing of our umbilical cord signal the beginning of an increasingly independent life of movement in all its glorious complexities. Our basic equipment for this journey through life is a three-part motor system – a leg/foot/toe system at the bottom that’s about half our body’s length and allows us to physically move from here to there and to kick things; an arm/hand/finger system in the middle that extends our reach about two feet and allows us to grasp, carry, throw, and write; and a neck/face/tongue system at the top that initiates digestion and activates a rhythmic flow of air molecules that move linguistic and musical information between and among brains.
These motor systems are excellent but finite. Humans have thus added technological extensions – such as shoes, ladders, wheels, boats, and airplanes – to increase the range and speed of our leg/foot/toe system; hammers, pliers, screwdrivers, gloves, grocery carts, guns, and pencils to increase the capabilities of our arm/hand/finger system; and knives, blenders, cooking, binoculars, microphones, and language to increase the capabilities of our neck/face/tongue system.
Much of our childhood is spent in the development and mastery of personal and technological motor skills. Children seem to intuitively know that if they hope to drive a car at 16, they better get on a tricycle at three. They have to master the integration of perception, arms, and legs in the control of wheels before their parents will give them the keys to the family car. They thus happily spend many hundreds of practice hours on bicycles and skateboards to master wheeled movement in natural space and time.” (p.20)
“Similarly, 21st-century children seem to intuitively know that they also have to master movement in cyber space and time. Video game controls are the electronic equivalent of tricycles, and children typically begin to play with the controls of simple games at about three. … But how do children begin the process of learning the myriad of such intentional movements that they must master? For example, if a mother sticks out her tongue at her observant infant a few hours after birth, the infant will intuitively reciprocate without any conscious knowledge of what a tongue is or prior experience with the complex act of projecting a tongue. The same is true of other early imitative behaviors, such as smiling and clapping hands. Further, many motor skills must begin to develop almost immediately, and most complex motor skills (such as tying a pair of shoes) can’t be learned solely through verbal directions.
So although effective movement is our brain’s defining property, much of the underlying neurobiology of its activation and mastery was an enigma until recently, when mirror neurons were discovered.” (p.21)
“Our brain contains myriads of neural networks that store and retrieve memories of general and specific facts, personal experiences, and motor sequences. We automatically execute frequently used motor sequences, such as grasping a glass, even though glass sizes differ, but we shift from such automatic behaviors to consciously executed variations if the immediate task is sufficiently different from the mastered skill. …
“Suffice it to sat at this point that several brain systems collaborate in learning, planning, and executing conscious and automatic movements. Two systems important to understanding mirror neurons and intentional movement are the motor cortex, which activates the specific muscles involved in a motor sequence, and the premotor area of the frontal lobes, which remembers and primes the motor sequence.
Giacomo Rizzolatti (Rizzolatti & Sinigaglia, 2007) and his team of Italian neuroscientists discovered mirror neurons in the early 1990s. They were studying the brain systems that regulate intentional hand movements in monkeys. they discovered that neurons in the premotor areas of the cortex that remember and prime motor sequences (such as how to grasp an object or to break open a peanut) activate milliseconds before the motor cortex neurons fire and the action occurs. The relevant premotor system thus forms an action sequence that activates the relvant motor cortex system that activates the relevant muscles.” (p.22)
“What amazed the scientists was the discovery one day that this premotor system also activates when their monkey simply observed someone else making that same intentional movement.
These premotor neurons don’t activate at the mere observation of a hand or mouth – only when it is carrying out a goal-directed action. Further, they respond to a hand but not to a tool that is grasping or moving an object because a brain’s motor areas regulate body parts and not tools. When the target of an action is an object (such as picking up a peanut) certain parietal lobe neurons are also activated. Scientists called this system the mirror neuron system.
This discovery was very significant because it identifies the brain systems that create a mental template of an observed intentional movement of someone else, and then prime the responsive imitative behavior. They don’t in themselves generate the response, but rather they enhance its probability. In effect, mirror neurons connect the subjective worlds of the actor and observer.
A cognitive system that allows a brain to automatically simulate and then to imitate the observed goal-directed movements of others would thus be an ideal learning system for complex movements, and that’s the critically important role that mirror neurons play in the maturation of a brain’s movement capabilities.
After the initial monkey research, neuroscientists used neuroimaging technologies to study mirror neurons in humans. They discovered that we have an incredibly complex mirror neuron system that encompasses our entire sensory and perceptual systems, allowing us to both simulate and empathize with the emotional lives and intentional states of others, driving our rich communicative and cultural life. Mirror neurons are thus central to our very existence as a social species, because our immature birth brain must master many motor skills during childhood” (p.23)
“Life would be chaotic, however, if the extended human mirror neuron system was simply a subconscious automatic system that imitated every observed intentional action. Our brain must thus rapidly determine if it’s simply enough to know the state of another person (and so to stifle a yawn) or to reciprocate a movement sequence (such as when someone initiates a handshake or a hug). A common communicated understanding about what’s important and appropriate must therefore exist in both the actor and the observer.” (p.24)
“We can observe the friendly movements of a handshake, but we cannot see what’s occurring inside a speaker’s mouth, where speech sounds are regulated. The mirror neuron system helps to explain how a child learns to speak.” (p.24) “Speech is a complex motor activity, so the infant initially babbles in incoherent imitation; but, over time, in a verbal environment, the child eventually, smooth articulate speech emerges.” (p.25)
Ref: (emphases in black bold and italics in original; emphases in blue bold mine) Robert Sylwester (2013) A Child’s Brain: Understanding how the brain works, develops, and changes during the critical stages of childhood. Skyhorse Publishing: New York