The brain and the up and down worlds

Whenever I was on a fun outing with my kids I would always have the very same reaction from my younger son at the end: “When can we do this again?” (but he would be happy to go home) and the very same reaction from my older daughter “What can we do now?” (and she wouldn’t be happy to go home). Needless to say that my daughter provides a much more difficult challenge for both her parents. But why are children, or people in general so different?

Daniel Z. Lieberman and Michael E. Long start their book on dopamine, The Molecule of More (2018) with an interesting metaphor. Humans experience two worlds, the down world, when you look down and see what you have got, the world of actualities, and the up world when you look up and see the potentialities beyond your daily horizon.

In your your brain the down world is managed by a handful of chemicals-neurotransmitters, they’re called-that let you experience satisfaction and enjoy whatever you have in the here and now. But when you turn your attention to the world of up, your brain relies on a different chemical-a single molecule-that not only allows you to move beyond the realm of what’s at your fingertips, but also motivates you to pursue, to control, and to possess the world beyond your immediate grasp. It drives you to seek out those things far away, both physical things and things you cannot see, such as knowledge, love, and power. Whether it’s reaching across the table for the salt shaker, flying to the moon in a spaceship, or worshipping a god beyond space and time, this chemical gives us command over every distance, whether geographical or intellectual. Those down chemicals-call them the Here & Nows -allow you to experience what’s in front of you. They enable you to savor and enjoy, or perhaps to fight or run away, right now. The up chemical is different. It makes you desire what you don’t yet have, and drives you to seek new things. It rewards you when you obey it, and makes you suffer when you don’t. It is the source of creativity and, further along the spectrum, madness; it is the key to addiction and the path to recovery; it is the bit of biology that makes an ambitious executive sacrifice everything in pursuit of success, that makes successful actors and entrepreneurs and artists keep working long after they have all the money and fame they ever dreamed of; and that makes a satisfied husband or wife risk everything for the thrill of someone else.

Both worlds are influenced by neurotransmitters, the down world by serotonin and others and the up world by dopamine. We all live in both worlds, but to a different extent. According to the authors, people with high levels of dopamine are more mobile, liberal, creative and better abstract thinkers, but are also more at risk for addictions, divorce and mental health problems such as schizophrenia and bipolar. People with higher levels of serotonin are more conservative, traditional and averse to change, but also more stable and reliable.

All in all, if you had a choice you would be better off choosing less dopamine. The long version of the dopamine receptor, the DRD4–7R is often dubbed the wanderlust gene. the allele originated as a rare mutational event and was recently affected by positive selection. The 7R allele is estimated to have emerged 40,000 to 50,000 years ago, which is the same time that major human migration occurred.

If bipolar genes promote emigration, these ambitious people would carry their risk genes with them, and we would expect to find high concentrations of bipolar genes in countries that have lots of immigrants. The United States is populated almost entirely by immigrants and their descendants. It also has the highest rate of bipolar disorder: 4.4 percent, which is about twice the rate of the rest of the world. Are the two related? Japan, which has almost no immigration, has a bipolar rate of 0.7 percent, one of the lowest in the world. People in the United States with bipolar disorder also start to have symptoms at a younger age, a marker of a more severe form of the illness. About two-thirds develop symptoms before the age of 20, compared to only a quarter in Europe. That supports the idea that the gene pool in the United States has a greater concentration of high-risk genes.

Single genes only have small effects, so it’s also important to look beyond genes. Colin G. DeYoung showed that the Big Five factors can be divided into two metatraits: Stability (serotonin-related) and Plasticity (dopamine-related). Stability is defined by one’s maintenance of stability and hypothesised to be related to the neurotransmitter serotonin, while Plasticity is seen in one’s adaptability to novelty and hypothesised to be related to the neurotransmitter dopamine. This is exactly what we would expect from biological adaptations to sedentism vs nomadism, respectively.

While early sedentary farmers would literally have lived mostly in a down world when working their fields, hunter-gatherers would have lived in a world beyond their immediate surroundings, dealing with potentialities most of the time. Where is it best to dig for those hidden underground tubers without wasting energy? Where could that animal that left this track have gone? What species? How far away is it already? Where is it headed? You get the idea. While farmers were deeply immersed in that down world, foragers would have been much more excited about that up world of possibilities.

Our modern world is basically a farmer world, with its 9–5 routine jobs and corporate hierarchy. It’s not a big surprise that people whose relatively recent ancestors were herders and foragers would be more restless in such a world and have a higher risk for all things unwanted in society. “The nail that sticks out gets hammered down” is a Japanese proverb used to describe conformity in Japanese culture. This proverb also makes it clear that genes that make you want to live too much in the up world are selected against socially and therefore experience negative evolutionary selection pressures.

How much we tend to live in this down world shows the relative lack of innovation in corporations despite an abundance of good ideas. Most good ideas are usually rejected by the ongoing organisation which is dedicated to getting today’s job done, and has little time or desire to make the new and different happen. This is how Nokia, the one-time leader in smartphones, quickly became a mobile phone dinosaur. Companies tend to prefer employing people who are good at coping with the down world and that can backfire very quickly when you operate in a fast-changing industry.

If you live more in a world of possibilities than the down world check out my book:

Originally published at on October 14, 2022.



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