Big brain evolution: changes in sapiens skull shape;addendum (Evolution)

by dhw, Tuesday, February 20, 2018, 11:15 (27 days ago) @ David Turell

DAVID: "the human adult does not have a completed pre-frontal cortex until age 25." […] "What is not complete until age 25 is the complexity of the neuron network and the ability to use that network to its full capacity."
dhw: How can the complexity be “complete” if it continues to add new connections after the age of 25?
DAVID: Simple: a newborn has a brain which is simple and must develop full complexity, which occurs on average finishing in the prefrontal cortex by age 25. This is medically accepted. Of course new complexity appears with new uses after that.

You do not seem to see the contradiction between your two statements above. The complexity is not complete until the age of 25 (i.e. it IS complete at 25). New complexity appears with new uses after that. If you can add something new to what exists, what exists cannot have been complete.

dhw: And what is a fully developed s/s/c?
DAVID: One that has the brain complexity to judge risk taking. Standard psychological theory requires full pre-frontal cortical development.
dhw: Why are you confining the activities of the self/soul to risk taking? And is judgement of risk the activity of the self/soul or of the brain, bearing in mind that according to your dualistic beliefs it is the self/soul and not the brain that does the THINKING.
DAVID: I used risk taking as an example. The judgment about the consequences of any new action by an individual is impaired or limited until the development of the prefrontal cortex is complete.

The development is never complete if it can add new complexities and uses. Most forms of human judgement are impaired or limited by a wide variety of circumstances. Only a God would be able to see the full picture of whatever we make judgements about. And if I were a dualist, I would vehemently deny that judgement depends on the pre-frontal cortex. Every statement you make about this confirms your materialism. See below.

dhw: What does this mean? The article makes it clear that experience shapes the brain’s development. I don’t suppose any of us are aware that our experiences are changing our brains, regardless of age.
DAVID: Please accept that full brain development from birth takes to an average age 25.

I am happy to accept that certain aspects of brain development are completed at around the age of 25. I am not happy to accept the claim that the brain as a whole stops developing at 25 if it continues to develop new complexities as a result of new uses. I am even less happy if a dualist informs me that judgement depends on the development of the pre-frontal cortex.

DAVID (in addendum re the appalling Florida shooting): What does this mean to our discussion? This kid could not reach a rational conclusion. By psychiatric theory his pre-frontal cortex was not physically developed enough to allow him to reach a proper analysis of the outcome of his plan, both as it applies to him and to his victims. […]

dhw: So if anyone aged 25-100 commits an act of indiscriminate slaughter, it must be because their fully developed pre-frontal cortex enables them to make a proper adult judgement. And everyone under 25 is devoid of the ability to reach rational conclusions because their pre-frontal lobe is not physically developed enough etc. I don’t believe it. Please see your response to my final sentence below and apply it, say, to a 24-year-old.

DAVID: Sorry about your disbelief but this is current medical theory about the length of adolescent judgment ability in regard to understanding the consequences of their actions. I've mentioned this many times in the past. Note his attorney is using it.

Defence attorneys use “diminished responsibility” of one sort or another in vast numbers of cases involving all ages, and ultimately it all ties up with the materialist argument that we do not have free will. I remain neutral, but you don’t. You have always argued that the soul/self has free will. Meanwhile, you have not responded to the logical extension of your argument: according to you, no one under the age of 25 is capable of reaching a rational conclusion because their pre-frontal cortex is not fully developed. A mass murderer over 25 has made a proper adult judgement because his pre-frontal cortex is fully developed. Is that what you believe?

But I am not denying what current medical theory tells us. A quick google reveals that the pre-frontal cortex is responsible for regulating our behaviour, emotions, social control, problem solving, abstract thinking, thought analysis, personal expression, decision-making…Not much left for the poor old soul to do, is there? I am not going to argue with it. The problem I have is when a dualist tells me that he accepts all this, but at the same time he believes it is his soul and not his brain that is responsible for regulating his behaviour, emotions, social control etc. etc. Something doesn’t quite add up, does it? What does current medical theory tell us about the soul?

The rest of your post illustrates the same dichotomy.

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