|Objectivism holds that all humans are rational animals. We all have the same general range of abilities. Cultural context and individual choice are the determinants that make us different. Furthermore, at any stage in life, any individual can choose to change in almost any manner. Learning to play a musical instrument might be harder for an older person, the fact remains that Tschaikowski chose a career in music at 23, and so, learning even the most complex tasks is possible at almost any age, given sufficient will.|
On the other hand...
No two human brains are alike — by design. Diversity propels evolution by enhancing a species' ability to adapt to changing environments. How does this relate to dyslexia? Hold that thought while we talk about the brains of children with reading difficulties.
Permanence of brain sex differences and structural plasticity of the adult brain
Bruce S. McEwen
The Effects of Music Training on Children's Brain and Cognitive Development
In their book, Brain, Mind, and Behavior, Floyd E. Bloom, a neuropharmacologist, and Arlene Lazerson, a professional writer specializing in psychology, state, “Experience [learning] can cause physical modifications in the brain.” This is confirmed by Michael Merzenich of the University of San Francisco. His work on brain plasticity shows that, while areas of the brain are designated for specific purposes, brain cells and cortical maps do change in response to experience [learning].
The article quoted below is significant, since it delivers more evidence to confirm these findings. The source is the TLC Magazine, Vol. 4(2), published by the South African Medical Association. The title of the article is “Drive a cab and increase your brain power”:
“A study in London has found that an area of the brain associated with navigation was larger in London's famed taxi drivers than in other people.
Drs. Ruben and Raquel Gur of the University of Pennsylvania found that women's brains have fewer neurons than men's brains on average, but are “wired together” more efficiently; visible structural differences help explain why women tend to be more skilled in verbal tasks, while men tend to be more adept at spatial tasks
Among the Gurs' other findings: Women have more tissue linking the brain's left and right hemispheres and therefore tend to employ "whole-brain" thinking, while men tend to employ one hemisphere or the other preferentially, depending on the task before them.
May 1999, Journal of Neuroscience
That we might be differentiable by the nature of our very different brains might explain much about human behavior. It might not change our perceptions of rights under law or moral action in a social context. Just because women are smarter than men, does not men that men should lose their rights to own property, for instance. (Of course, that is a self-interested assertion on my part. )