Human Nature

Did Money Eat Our Brains?

Our heads got bigger for two million years. For at least ten thousand years, they’ve been getting smaller. Is the Money-Zombie Apocalypse upon us?

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By Steve Roth

“This invention will produce forgetfulness in the minds of those who learn to use it, because they will not practice their memory. Their trust in writing, produced by external characters which are no part of themselves, will discourage the use of their own memory within them. You have invented an elixir not of memory, but of reminding.”

— Thamus, King of all Egypt, to the inventor god Theuth, in Socrates’ whimsical fable in Plato’s Phaedrus*

Human brains have been getting smaller for ten or twenty thousand years.

After growing rapidly for a couple of million years, doubling from roughly 750 to 1,500 cubic centimeters, human brains have shrunk by about ten percent over just ten or twenty millennia. (So they’ve been getting smaller maybe twenty times faster than they got bigger.) Imagine taking an ice cream scoop out of your brain. That’s about the size of it.

What’s with that? Absent some remarkable confluence of brain-enhancing mutations ten or twenty thousand years ago (none discovered so far), we have to assume that our memory and/or processing capacity is less than it was. Big brains are darned expensive to build and run (in addition to killing lots of mothers in childbirth), so there’s serious natural-selection pressure preferring smaller ones. But how did those pressures shift to alter the cost/benefit tradeoff so rapidly, opting for smaller brains and presumably less capacity?

There are quite a few theories and speculations explaining our vanishing gray matter. You can read some about them here. None has gained wide acceptance. Several have been pretty thoroughly rejected.

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I’d like to suggest another: money did it to us.

The most popular explanation these days for humans’ million-year brain expansion is the need for social accounting in steadily larger and more complex groups. Keeping track of all those interactions with all those people over a lifetime is a memory- and processor-intensive task. Add to that: gossip, language’s unruly stepchild — keeping track of what all those people said about all those other people’s interactions. Those with the brain power to manage that memory (and so “win” that complex social game) ended up with more grandchildren. Voilà: bigger brains.

So what happened back then to lessen those brain-power demands and advantages? In one word, writing. And in its earliest forms, writing just consisted of tallies. Tallies of various types extend back tens of thousands of years, and became widespread in the last ten or twenty millennia. (So the timing fits.) These tallies are numeric accountings, employing some unit(s) of account to tot up the value of tribute goods, services rendered, commodities, everyday exchanges, dowries, bride-prices, and endless others. Tallies using arbitrary units of account constitute the social-accounting technology we call “money.” (This is all long before coins were invented, around 700 BCE.) We think innately in terms of something resembling balance sheets, though not of course of the formal variety that emerged with double-entry accounting. We see similar “tallying up” and later reciprocity in some animals, but to a far lesser degree.

Written tallies provided a way to keep track of some portion of those social interactions and relationships — gives and takes, owning and owing — clearly a portion that was considered important, or they wouldn’t have been written down. Accounting tallies won’t help you remember your brother-in-law’s report of what your second cousin said about your sister’s boyfriend, but they will save you from having to remember that he owes you something for the two pigs and the bushel of yams you gave him three years ago.

The memory-offloading utility of writing then expanded vastly five thousand years ago, when it started to encompass words — the infinite expanse of combinatorial language.

Those with smaller brains who took advantage of this outsourcing technology could succeed as well as big-brainers, without sacrificing calories (and childbearing mothers’ lives) to those big brains. They had more grandchildren, and smaller brains spread through the population.

In short, the technology of money (then writing), passed down through cultural learning, changed the selection pressures on human evolution. The benefit-to-cost ratio of big brains went down, so brains got smaller.

This cultural/genetic co-evolution is exactly what happened to our large intestines, which are small by primate standards. We figured out how to process food before eating it, using chipping, grinding, soaking, chopping, etc., and especially cooking. These technologies predigest our food, and remove or transform many poisons that other primates process within their bodies. Spread and passed down through the generations via cultural learning — an innate ability that is almost purely human — these culturally learned practices made the larger large intestine unnecessary. So bodies that used less resources by growing and maintaining smaller large intestines tended to live longer, and have more grandchildren. (The small intestine didn’t shrink, by the way; its full length is still needed to absorb nutrients after the food is broken down.)

This same process affected almost every part of our bodies. Because of our inventions, both technological and social — transmitted and spread through cultural learning and cultural evolution — we’re almost certainly much weaker than our common ancestor with chimpanzees. (An adult male chimpanzee is strong enough to break a man’s back.) Our weak and ineffectual bodies have co-evolved out of our cultures to the point that without our culturally transmitted knowledge and practices, we simply could not survive.

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It’s possible that — for better or for worse — we’ve evolved to the point that we couldn’t survive without money.

That may or may not be a scary thought. But when it comes to outsourcing our brains, ask yourself: can you remember your best friend’s phone number without checking your smart phone?

Socrates wept.

Another way to think about it: we’ve domesticated ourselves. Domesticated animals have smaller brains than wild animals, presumably because they’ve outsourced some of their brain-work — to humans. We’ve outsourced it to…other humans, the human collective, the “hive mind” that collects, retains, and transmits cultural learning, and to the technologies transmitted through culture. We are nature’s best learning and teaching machines.

Money is one prime example of a core human technology that evolved and spread through culture, and cultural learning. Our evolved, innate ability for that kind of cultural learning is — to co-opt the title from Joseph Henrich’s great book — the secret of our success. Credit for much of the thinking here should go to him.


* Socrates was speaking, and Plato was writing, in a time when bards could still sing all twelve books of the Trojan cycle from memory (we’ve got two of those books, the Iliad and the Odyssey). More precisely, they could sing-and-improvise, inserting familiar “pop-music” jingles, epithets, and catch-phrases that made the words and music both metrical and memorable — and catchy. But those bards were disappearing, even as writing became widespread. Socrates and Plato were witnesses to the very cultural transition described here — just as we are witnesses, today, to the brain-eating effects of the iPhone. Kids these days.

2016 August 22

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  • Christian Holata

    The average person – say a tax accountant – spent 5 years in order to fill their minds with systemic horse shit. Then they waste 50 hours a week applying their systemic horse shit in order to prolong the suffering for everybody in this socioeconomic insanity.

    Then they get stuck in traffic jams and when they finally arrive home they don’t tend to engage in wisdom and intelligence improving activities but to hang out with other zombies of the system and/or to watch an episode of Zombocalypse IV on Amazon Prime.

    Their whole world view is defined by the narrative of fictional debt and “not enough money”. They believe in #bullshitjobs, poverty, war, pointless competition and destroying everything that matters in the name of economic “growth”.

    So money – or rather money which got created as interest bearing debt – is not only tremendously limiting our collective intelligence, creativity, empathy and general development … it’s also shaping the little remaining potential in horrible ways … it’s programming and conditioning the vast majority into highly materialistic, fear and ego driven morons.

    All of this is much more acute and important than the evolutionary long-term implications of technology on our bodies and/or minds. The big issue is not money … the big issue is the way we create money as interest bearing debt.

    A society which features a cooperative monetary system and a debt/interest free #basicincome instead of poverty, #bullshitjobs and climate change would look _COMPLETELY_ different in _EVERY_ way. It would be empathic, creative, intelligent, evolving, etc., etc., …

    Evolution is stifled by this narrative of artificial scarcity and fictional debt which central banks and their political puppets are flooding us with nonstop … not by money itself.

  • Duncan Cairncross

    I would like to see some data backing up that claim
    As far as I can see people were bigger and fitter (and probably had bigger brains) as hunter/gatherers – when agriculture came along so did malnutrition and smaller people

    So we have a probable step downwards in brain size about 4,000 years ago

    BUT in the last hundred years
    People have been growing taller (and presumably increasing in brain size) -due to nutrition
    Also we have the “Flynn Effect”

    “The Flynn effect is the substantial and long-sustained increase in both fluid and crystallized intelligence test scores”
    Showing an INCREASE in intelligence over the last century

    Absent any new data I would describe this article as nonsense

  • X-7

    Nice knowledge-dot connecting. Really interesting. Didn’t know our brains were shrinking. Important. Thank you.
    Shrinking bio processor … cultural coding feeds back on biological coding? I think so.
    Adding complexity: Think the generation of code, including monetary code, is fundamental physics: relationship infrastructure. (Might David Deutsch’s Constructor Theory of Information support this?? Intuit that per my limited understanding, not sure.)
    Attached graphic (yes, tad obnoxious, apologies) is part of foundation for this piece:
    The Price Is Wrong:
    Software code is to monetary code as alphabet code was to pictograph code … and think that software code is a survival-necessary coding structure for a eusocial species attempting to process / navigate environs that are complexifying exponentially. Bryan Atkins

  • Candice H. Brown Elliott

    This “decrease” in brain size has also coincided with the rise in agraculture and life expectancy of adults (infant mortality remained much the same over this period and only very recently decreased due to better healthcare). Brains shrink with age. Thus, the average age of a skull has increased… and as a consequence, the average size of the brain that was contained in said older average aged skull has decreased. No, we are NOT getting “dumber”.

  • George McKee

    Dare I say that this is typical male-oriented thinking that “bigger = better”? Elephants and dolphins and whales have bigger brains than humans. Does this mean that the stories about elephants’ memories should be taken as true? We don’t even have scientific consensus on the memory capacity of humans.

    Even the cop-out of “all other things being equal” doesn’t really apply to brain size and intelligence. The myth of the slow, stumbling giant could apply to brains as well: shorter neural path lengths could mean faster thinking, while the longer pathways in bigger brains could lead to slower reactions. In a more densely connected social world enabled by agriculture, out-thinking your peers may mean getting to the rewards first.

    Evolution can come up with other innovations that affect thinking beyond simple size changes. Invertebrates such as octopuses and squids have bigger neurons than vertebrates, because vertebrates have acquired glial cells whose myelin allows nerve impulses to be isolated from each other far more effectively and allows those impulses to travel the length of neural axons far more rapidly. This creates efficiencies that allow vertebrate neurons to be packed together more closely, giving greater density of processing capability. Are these evolutionary processes towards higher density of connections occurring even today? Maybe human brains are shrinking in the same way that computer memory and processor features are shrinking, where your phone is far more powerful than a desktop PC of just a few years ago.

    What other innovations are possible and ongoing in brain and neuron capability? We don’t have a clue. Advanced genomics, proteomics and “connectomics” may help identify anomalies in neurodevelopmental processes that may have cognitive consequences, but connections to economics are exceedingly far-fetched.