- Published: September 26, 2012
- Written by Joshua P. Preston
In an article published in the Proceedings of the National Academy of Sciences, researchers at the Columbian College of Arts are giving further insight into the evolutionary history of our cognitive development. In studying the brains of both chimpanzees and humans, they discovered that myelin, which is "fatty insulation surrounding axon connections of the brain", ceases developing in our distant cousins long before it does for us. In fact, in humans it fully develops only once we have entered early adulthood.
The developmental timing of myelination is important because it establishes connectivity among parts of the growing brain, which is essential to higher-order cognitive functions, such as decision-making and emotional regulation. These cognitive functions are known to mature relatively late in humans, after the time of adolescence. Also, this period of persistent myelin development during early adulthood in humans is a time of particular vulnerability to neuropsychiatric diseases, including schizophrenia, bipolar disorder, and depression.
This research is important for several reasons but I find it particularly interesting since it affirms, once again, that our legal system must accommodate the full diversity of brains that find their way before the bench. Right now, the legal system does differentiate between "youth" and "adulthood" but does so on purely artificial lines - if you commit a crime the day before your 18th birthday, you will be held to a different level culpability than if you had committed said crime a day after. Such distinctions are necessary since a line must be drawn somewhere but such lines are arbitrary and assumes that at this level of adulthood one has a full understanding of the consequences of their actions. Research like this reminds us that that is not true. Instead of having a bright line, we should be more flexible in how we distribute punishment - and once we do this, it will only follow that a fair and equitable legal system will be one that scales punishment according to the brain on trial whether we regard the individual as an "adolescent" or not.