NOTES FOR WHAT SOME CALL POST-BIRTH GESTATION
I'm using some earlier sequences to deal with each issue in order. This one is the second stage of human development, but the last of the brain to develop, so it extends through several stages of maturation. I begin to suspect that some people never really develop through the last stage and that what some people attribute to college education, is merely the brain achieving maturation.
This entry is preparation for the next, which is about writing as narrative through the whole length of life. Stories are a way of testing the ideas developed in the pre-frontal cortex. It is also the location of empathy, which is a way of inhabiting stories. Some people feel this is the future of evolution, because when people tell the stories and understand each other, the ensuing progress helps the survival of all.
Another reason for liking to have cats around is that they have no pre-frontal cortex. That part of the brain that is behind the forehead. Cats have no forehead. This is the reason humans say that cats are amoral, because "morality" is in that part of the brain. Both Aesop and Napi represent progress and survival, but cats tell no stories.
First a quick review of the main parts of the brain. (Wiki)
- Cerebrum: This is the biggest part of the brain, and it's responsible for thinking, remembering and feeling. This is where the cerebral cortex and its various lobes (including the frontal and temporal lobes) reside.
- Cerebellum: The area in charge of motor control.
- Brain stem: The engine driving many of your baby's most vital functions, including heart rate, breathing and blood pressure.
- Pituitary gland: This pea-sized gland releases hormones into your body that are responsible for growth, metabolism and more.
- Hypothalamus: This area deals with body temperature, hunger and thirst, sleep and emotions.
The evolutionary appearance of the pre-frontal cortex is a marker for the line between mammals and humans. Primates may be somewhere in between, waiting for the evolution of words, but they have at least a Theory of Mind and signs of empathy, or at least sympathy.
Each paragraph below is from a Google explaining the prefrontal cortex:
"Many authors have indicated an integral link between a person's will to live, personality, and the functions of the prefrontal cortex. This brain region has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior."
"The most typical psychological term for functions carried out by the prefrontal cortex area is executive function. Executive function relates to abilities to differentiate among conflicting thoughts, determine good and bad, better and best, same and different, future consequences of current activities, working toward a defined goal, prediction of outcomes, expectation based on actions, and social "control" (the ability to suppress urges that, if not suppressed, could lead to socially unacceptable outcomes)."
"The frontal cortex supports concrete rule learning. More anterior regions along the rostro-caudal axis of frontal cortex support rule learning at higher levels of abstraction."
"The brain develops in a back to front pattern, and the prefrontal cortex is the last portion of the brain to fully develop. ... Experience can play a role in the development of the prefrontal cortex, and children exposed to a variety of stimuli and challenges may develop more quickly."
"The rational part of a teen's brain isn't fully developed and won't be until age 25 or so. In fact, recent research has found that adult and teen brains work differently. Adults think with the prefrontal cortex, the brain's rational part."
In the days when people believed in lobotomies, they deliberately cut the prefrontal cortex connections with the rest of the brain, ties that are multiple and crucial. The result was a pre-human. A mammal, but not much different from a chimp. But looking back to paleo-times, it's impossible to define the prefrontal cortex. It's continuous and only gradually appeared. Method of definition makes a difference in even exactly where the pre-frontal cortex stops being "pre-". But we could look at the container of the part, which persists in bone fossils.
"The supraorbital ridge is a nodule or crest of bone situated on the frontal bone of the skull. It forms the separation between the forehead portion itself (the squama frontalis) and the roof of the eye sockets (the pars orbitalis). Normally, in humans, the ridges arch over each eye, offering mechanical protection. In other primates, the ridge is usually continuous and often straight rather than arched. The ridges are separated from the frontal eminences by a shallow groove. The ridges are most prominent medially, and are joined to one another by a smooth elevation named the glabella.
Typically, the arches are more prominent in men than in women, and vary between different ethnic groups. Behind the ridges, deeper in the bone, are the frontal sinuses.
"The most composed articulation of the spatial model was presented by Moss and Young (1960), who stated that "the presence… of supraorbital ridges is only the reflection of the spatial relationship between two functionally unrelated cephalic components, the orbit and the brain" (Moss and Young, 1960, p282). They proposed (as first articulated by Biegert in 1957) that during infancy the neurocranium extensively overlaps the orbit, a condition that prohibits brow ridge development. As the splanchocranium grows, however, the orbits begin to advance, thus causing the anterior displacement of the face relative to the brain. Brow ridges then form as a result of this separation."
(Try working "splanchcranium" into a conversation.)
Reading the analysis of very early skulls is very strange and focussed on small changes over time. One theory is all about the structure being created by the engineering stresses of the face holding up everything else and therefore the force of chewing (they say mastication) creates a strong structure but soft food makes the face collapse and the forehead bug out. So does that make the brain cavity in the prefrontal region bigger or less?
This foto troubled me:
Wolf Robe or Ho'néhevotoomáhe (b. 1838-1841, d. 1910, Oklahoma)
A Southern Cheyenne chief of the southern Cheyenne.
The medallion is a peace medal.
Is his nose so big and his forehead so short because he could smell forbidably but had no moral feelings about it? Is he an excellent mammal but a limited thinker?
This is a European soccer player. Small nose. Thick brow. Morality?
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