The Mathematics of “Big Brains” / Evolution

From PBS Science, March 2017

Why did humans evolve big brains? We don’t know, but math can help

Where is the math in this article? You’ll need to go to original paper.

by Kristin Hugo

A new model published Thursday in PLOS Computational Biology mathematically illustrates what led to the evolution of humans’ abnormally large brains. (A cliché that is not true – we have the brain the “fits” us.)

Evolutionary biologists devised these equations to tease apart the relationship between human brain size and the cost of maintaining a large brain. (This is physics: the human body and the evolutionary processes that shaped it, conform to physical laws) Over the last few decades, the pace and stages of brain growth in humans have become clearer. From birth to preschool, our brains quadruple in size. Our brains reach 90 percent of their final size by six years old, and they continue to grow slowly through adolescence until stopping in our mid-20’s.

The question is: Why?

Anthropologists have hypothesized — made educated speculations — about what factors in human evolution drive this pace. For example, newborns heavily rely on their families, so they can develop strong social bonds during their youth. (This is stated as if newborns have the intent to rely on other people, in order to develop social bonds; this is backwards! Human infants must rely on other people because they are helpless. The infant displays behavior that ought to elicit parental bonds, but in fact, there are a very high number of parents who do not respond appropriately –  this response ought to be instinctual, but as we commonly see in many domestic animals, this instinctual bond has been interrupted, is undeveloped, or damaged in the mother and other adults)

As humans get older, we increasingly learn to be self-sufficient (or not!); (learn to) use tools and learn about our environments. Scientists speculate both of these habits (?) contribute to brain growth, but they don’t know which of these factors or others have the greatest bearing. We are way off track already – Brain growth depends on NOURISHMENT and adult care – the protection and guidance that will allow the child  to learn to “operate” its body, regardless of the society, culture or group size that the infant will grow within.

A standard mathematical model (of what?) could provide clarity by quantitatively comparing hypotheses. (Or show that “educated speculations” lack credibility as descriptions of “the real world”

You’d think that PBS could hire a Competent science writers, or at least employ a science editor! This is piss-poor, garbled reporting!  An Asperger pet peeve: If we are going to “educate” the public about scientific Activity, we need Accurate language! Otherwise it’s just Blah, blah, blah.

Anthropologists can plug in their hypotheses to the model (not really) which then predicts brain size from birth to adulthood based on those numbers. If those numbers match what we know about the pace of human brain development, then the model supports the hypothesis. (What numbers? This is gobbled-gook!) “With this model, you can obtain predictions for each of the hypotheses to see which hypothesis yields a better prediction,” said evolutionary biologist Mauricio González-Forero of Université de Lausanne in France, who led the study. Aye, yai, yai!

The final model states that adult skill level equals adult brain mass times the cost of maintaining brain tissue divided by the cost of memory times a constant. Stated in laymen’s terms, this idea means as adult brain mass increases, so too does adult skill, assuming that the costs of maintaining the brain mass and memory stay constant. (Aye, yai, yai!!!!)

These costs include eating a lot in order to maintain the brain. (of the right kind of food) Brains make up 2 percent of our bodies, but consume 20 percent of our oxygen and sugars in our food to sustain the activity of billions of neurons. This mental gorging could have been a disadvantage for early humans thousands of years ago, because bigger diets, consisting of more calories, means having to spend more time hunting and foraging for food. If their evolving brains drained too much food and oxygen, then they might have been too tired to fend for themselves. (Yikes!)

God help us! Another naïve neurotypical narrative! First – this is backwards: IF food X provides more calories per “effort to obtain it” (work), you’re in luck – you will focus on obtaining food X: (bears, sharks, and millions of species do this) For early humans, exploiting a new “option” (such as animal protein) results in more calories, a benefit that then can be maximized by improving and tailoring technology toward getting this food AND for other activities as well. Once this “boost in calories” becomes more available, better brain nourishment (especially in children) provides more “brain power” for  developing new technologies and devising better strategies for survival. It’s a feedback process. ) 

Modern social humans (Americans) seek out “crappy food” that deprives them of the nutrition necessary for even minimal brain and body health. This is bad enough, but to starve our children’s brains is a crime!

While there is debate among anthropologists, many believe that social interaction is a major factor in increasing brain size. Knowing people, communicating with them and maintaining relationships takes a lot of brainpower. This is recent “social narrative” about agricultural societies; regardless of “social” influence, the brain runs on REAL ENERGY supplied by FOOD. What we see in contemporary hyper-social juvenalized humans is overconsumption of “crappy food” which fails to  provide adequate  nourishment. Compounded by “social demands” that consume too much of a child’s energy, leaves less energy for children to develop healthy brains and bodies: in many children, learning becomes impossible. What we see is a “shrinking” of brain size over the last 10,000 years of human domestication)

González-Forero’s model counters this narrative and asserts that humans gain more intelligence as they learn to use technology, which University of Wisconsin-Madison evolutionary anthropologist John Hawks describes as a controversial but revealing take on brain development. (Controversial= whacky = magical thinking) Many anthropologists look at the pace of brain growth in terms of social interactions, he added, but “this paper is saying maybe social relationships don’t have anything to do with it. It’s really neat to see such a cool, clear statement of that because it gives us a target.”

The socially-obsessed “naïve narrative” of the evolution of human brain has taken over anthropology and related “human sciences” – at the expense of logical reasoning  grounded in the reality of physical environments.

Logically, we can go much further: social activity can be detrimental to human survival, Energy expended on social activity consumes far more energy than it “supposedly” supplies; social activity redistributes food, water and fossil fuels to ultra-greedy nations, thus depriving millions of human beings the “nourishment” that children must have in order to develop. “Saving” children, by handing out “just enough gruel” to keep them alive temporarily, results in underdeveloped and damaged brains, and is unconscionable social activity.

Contemporary  humans suffer from this very real food-energy drain. We cannot provide clean water and proper nourishment to hundreds of millions of human children, but “spend” enormous amounts of energy on projects with “no energy return” – war, environmental destruction, and billions of useless products (can’t eat them!), the production of which consumes vast amounts of energy (especially human energy) that is needed for “brain growth”.



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