Picture a power plant with three separate layers of technology from three different eras, all still in operation, stacked one atop the other. The most recent layer, computer technology, is functioning via vacuum tubes from the 1940s, which in turn control still older pneumatic mechanisms that rely on pressurized gases. What is the purpose of such a convoluted system? Wouldn’t it have been more elegant and efficient to simply start over with the most modern technology? Probably, but the need for continuous power precluded shutting the system down while the entire plant was rebuilt. Instead, engineers continued to build onto existing structures. John Allman, evolutionary neuroscientist from the California Institute of Technology, points out that the triple-layered, or triune, human brain was constructed on essentially the same principles.
Evolution’s reputation as “survival of the fittest” is often taken to mean evolution toward perfection. More accurately, it means employment of the best available adaptation at the time of event, such as abrupt climate change or the outbreak of a new disease. Like the power plant, nature isn’t able to take the development of a species offline and wait for the optimal solution. If the adaptation or mutation works, the species survives to play another day. The human brain is an undoubtedly an engineering marvel, but like any structure that’s been repeatedly renovated, it has a few quirks.
Some people balk at the idea that the human brain is less than optimal. But think about it. The period of human existence is relatively short. Bacteria have existed for 3 billion years, and mammals for 300 million. Humans have been around for a few hundred thousand, at most. Language, complex culture and capacity for deliberate thought, the newest developments in the evolution of humankind, have been around for about 50,000 years. By evolutionary standards, that’s not much time to get the kinks out. The genome of humans and monkey are 98.5% identical. That means the vast majority of our genetic material evolved through creatures who didn’t have language, didn’t have culture and didn’t deliberately reason, so those capacities have been built on a genetic structure originally adapted for very different purposes.
In the video clip below, Daniel Siegel, clinical professor of psychiatry at the UCLA School of Medicine, demonstrates a hand model of the brain. The wrist and palm represent the brain stem, or reptile brain, which dates from at least half a billion years ago. It performs most of our bodily housekeeping including respiration, balance, alertness and other functions that were as critical to a dinosaur as they are to a human. (If you can’t see the UTube video player below, please click on this link https://www.youtube.com/watch?v=DD-lfP1FBFk
Curling our thumb into the palm of our hand shows us the location of the limbic or mammalian brain. It has more to do with our animal survival than with our human potential, functions involving what some researchers call the “four F’s”: fighting, feeding, fleeing, and … behaviour associated with reproduction. The amygdala and the hippocampus reside here, and together they allow us to feel and create memories of rage, fear, and pleasure. The amygdala, in particular, is a key player in the human tendency to irrational and over-reactive fear, a tendency that kept us alive on the savannah, but which actually works against the nuanced response required to meet modern fears and frustrations such as financial worries, traffic congestion and your mother in law’s criticisms.
This more subtle behaviour is the job of our higher brain, the neo-cortex, illustrated by drawing our four fingers down over the thumb. This thin, blanket-like layer governs things such as language and decision making, and like the power plant, does so in ways that often depend upon the older systems. With complex, sticky root systems, the cortex adheres to the deeper structures of the brain through a hopelessly incomprehensible thicket of neural connections. The vitally human area, the mid pre-frontal cortex (mid -PFC) is in the space directly behind our foreheads, and is represented by the fingernails of our two middle fingers. The mid-PFC is the home of attuned communication, insight, intuition, empathy, moral reasoning, fear regulation, emotional balance and flexibility in response.
Ideally, all parts of our brain function and communicate fluidly and gracefully, the separate elements linked into a cohesive whole. Dr. Siegel calls this integration, and shares many examples in his book Mindsight . Integration is achieved through developing and thickening that sticky root system from the neo-cortex down into the brain stem, allowing us to become responsive, rather than reactive. We are able to avoid the extremes of chaotic behaviour on one hand and rigidity and inflexibility on the other. Integration helps us avoid anxiety, depression, obsession, and addiction, which plague us when the neural connections between our older brains and our neo-cortex are less well developed. Our internal worlds become clearer, and we are able to meet the external world with poise and flexibility.
How do we promote integration? Through mindfulness meditation. Easily said and actually, fairly easily done. Little or no equipment or capital outlay required. There are numerous ways to go about it, including guided meditation downloads for your iPod and classes in meditation itself. Mindfulness Based Stress Reduction clinics, available in many major cities, are an excellent resource.
The human brain is a marvellous and delicate instrument whose wonders are still revealing themselves. We threw a lot of challenge its way with the demands of the industrial revolution, and have revved up the speed exponentially with the digital revolution and the internet. Tools like mindfulness meditation help level the playing field and give our brain a better chance of meeting the demands for instant and continuous communication. Think of it as a booster shot for evolution.