7
Memory Overload
EVOLUTION DID NOT ENDOW HUMANS with the ability to play
football. True, it produced legs for kicking, elbows for fouling and mouths for
cursing, but all that this enables us to do is perhaps practise penalty kicks by
ourselves. To get into a game with the strangers we find in the schoolyard on any
given afternoon, we not only have to work in concert with ten teammates we
may never have met before, we also need to know that the eleven players on the
opposing team are playing by the same rules. Other animals that engage
strangers in ritualised aggression do so largely by instinct – puppies throughout
the world have the rules for rough-and-tumble play hard-wired into their genes.
But human teenagers have no genes for football. They can nevertheless play the
game with complete strangers because they have all learned an identical set of
ideas about football. These ideas are entirely imaginary, but if everyone shares
them, we can all play the game.
The same applies, on a larger scale, to kingdoms, churches and trade
networks, with one important difference. The rules of football are relatively
simple and concise, much like those necessary for cooperation in a forager band
or small village. Each player can easily store them in his brain and still have
room for songs, images and shopping lists. But large systems of cooperation that
involve not twenty-two but thousands or even millions of humans require the
handling and storage of huge amounts of information, much more than any
single human brain can contain and process.
The large societies found in some other species, such as ants and bees, are
stable and resilient because most of the information needed to sustain them is
encoded in the genome. A female honeybee larva can, for example, grow up to
be either a queen or a worker, depending on what food it is fed. Its DNA
programmes the necessary behaviours for whatever role it will fulfil in life.
Hives can be very complex social structures, containing many different kinds of
workers, such as harvesters, nurses and cleaners. But so far researchers have
failed to locate lawyer bees. Bees don’t need lawyers, because there is no danger
that they might forget or violate the hive constitution. The queen does not cheat
the cleaner bees of their food, and they never go on strike demanding higher
wages.
But humans do such things all the time. Because the Sapiens social order is
imagined, humans cannot preserve the critical information for running it simply
by making copies of their DNA and passing these on to their progeny. A
conscious effort has to be made to sustain laws, customs, procedures and
manners, otherwise the social order would quickly collapse.
For example, King
Hammurabi decreed that people are divided into superiors, commoners and
slaves. Unlike the beehive class system, this is not a natural division – there is no
trace of it in the human genome. If the Babylonians could not keep this ‘truth’ in
mind, their society would have ceased to function. Similarly, when Hammurabi
passed his DNA to his offspring, it did not encode his ruling that a superior man
who killed a commoner woman must pay thirty silver shekels. Hammurabi
deliberately had to instruct his sons in the laws of his empire, and his sons and
grandsons had to do the same.
Empires generate huge amounts of information. Beyond laws, empires have
to keep accounts of transactions and taxes, inventories of military supplies and
merchant vessels, and calendars of festivals and victories. For millions of years
people stored information in a single place – their brains. Unfortunately, the
human brain is not a good storage device for empire-sized databases, for three
main reasons.
First, its capacity is limited. True, some people have astonishing memories,
and in ancient times there were memory professionals who could store in their
heads the topographies of whole provinces and the law codes of entire states.
Nevertheless, there is a limit that even master mnemonists cannot transcend. A
lawyer might know by heart the entire law code of the Commonwealth of
Massachusetts, but not the details of every legal proceeding that took place in
Massachusetts from the Salem witch trials onward.
Secondly, humans die, and their brains die with them. Any information
stored in a brain will be erased in less than a century. It is, of course, possible to
pass memories from one brain to another, but after a few transmissions, the
information tends to get garbled or lost.
Thirdly and most importantly, the human brain has been adapted to store and
process only particular types of information. In order to survive, ancient huntergatherers
had to remember the shapes, qualities and behaviour patterns of
thousands of plant and animal species. They had to remember that a wrinkled
yellow mushroom growing in autumn under an elm tree is most probably
poisonous, whereas a similar-looking mushroom growing in winter under an oak
tree is a good stomach-ache remedy. Hunter-gatherers also had to bear in mind
the opinions and relations of several dozen band members.
If Lucy needed a
band member’s help to get John to stop harassing her, it was important for her to
remember that John had fallen out last week with Mary, who would thus be a
likely and enthusiastic ally. Consequently, evolutionary pressures have adapted
the human brain to store immense quantities of botanical, zoological,
topographical and social information.
But when particularly complex societies began to appear in the wake of the
Agricultural Revolution, a completely new type of information became vital –
numbers. Foragers were never obliged to handle large amounts of mathematical
data. No forager needed to remember, say, the number of fruit on each tree in the
forest. So human brains did not adapt to storing and processing numbers. Yet in
order to maintain a large kingdom, mathematical data was vital. It was never
enough to legislate laws and tell stories about guardian gods. One also had to
collect taxes. In order to tax hundreds of thousands of people, it was imperative
to collect data about peoples incomes and possessions; data about payments
made; data about arrears, debts and fines; data about discounts and exemptions.
This added up to millions of data bits, which had to be stored and processed.
Without this capacity, the state would never know what resources it had and
what further resources it could tap. When confronted with the need to memorise,
recall and handle all these numbers, most human brains overdosed or fell asleep.
This mental limitation severely constrained the size and complexity of
human collectives. When the amount of people and property in a particular
society crossed a critical threshold, it became necessary to store and process
large amounts of mathematical data. Since the human brain could not do it, the
system collapsed. For thousands of years after the Agricultural Revolution,
human social networks remained relatively small and simple.
The first to overcome the problem were the ancient Sumerians, who lived in
southern Mesopotamia. There, a scorching sun beating upon rich muddy plains
produced plentiful harvests and prosperous towns. As the number of inhabitants
grew, so did the amount of information required to coordinate their affairs.
Between the years 3500 BC and 3000 BC, some unknown Sumerian geniuses
invented a system for storing and processing information outside their brains,
one that was custom-built to handle large amounts of mathematical data. The
Sumerians thereby released their social order from the limitations of the human
brain, opening the way for the appearance of cities, kingdoms and empires. The
data-processing system invented by the Sumerians is called ‘writing’.
Signed, Kushim
Writing is a method for storing information through material signs. The
Sumerian writing system did so by combining two types of signs, which were
pressed in clay tablets. One type of signs represented numbers. There were signs
for 1, 10, 60, 600, 3,600 and 36,000. (The Sumerians used a combination of
base-6 and base-10 numeral systems. Their base-6 system bestowed on us
several important legacies, such as the division of the day into twenty-four hours
and of the circle into 360 degrees.) The other type of signs represented people,
animals, merchandise, territories, dates and so forth. By combining both types of
signs the Sumerians were able to preserve far more data than any human brain
could remember or any DNA chain could encode.
19. A clay tablet with an administrative text from the city of Uruk,
c.3400–3000 BC. ‘Kushim’ may be the generic title of an officeholder, or the
name of a particular individual. If Kushim was indeed a person, he may be
the first individual in history whose name is known to us! All the names
applied earlier in human history – the Neanderthals, the Natufians, Chauvet
Cave, Göbekli Tepe – are modern inventions. We have no idea what the
builders of Göbekli Tepe actually called the place. With the appearance of
writing, we are beginning to hear history through the ears of its
protagonists. When Kushim’s neighbours called out to him, they might
really have shouted ‘Kushim!’ It is telling that the first recorded name in
history belongs to an accountant, rather than a prophet, a poet or a great
conqueror.1
At this early stage, writing was limited to facts and figures. The great
Sumerian novel, if there ever was one, was never committed to clay tablets.
Writing was time-consuming and the reading public tiny, so no one saw any
reason to use it for anything other than essential record-keeping. If we look for
the first words of wisdom reaching us from our ancestors, 5,000 years ago, we’re
in for a big disappointment. The earliest messages our ancestors have left us
read, for example, ‘29,086 measures barley 37 months Kushim.’ The most
probable reading of this sentence is: ‘A total of 29,086 measures of barley were
received over the course of 37 months. Signed, Kushim.’ Alas, the first texts of
history contain no philosophical insights, no poetry, legends, laws, or even royal
triumphs. They are humdrum economic documents, recording the payment of
taxes, the accumulation of debts and the ownership of property.
Partial script cannot express the entire spectrum of a spoken language,
but it can express things that fall outside the scope of spoken language.
Partial scripts such as the Sumerian and mathematical scripts cannot be
used to write poetry, but they can keep tax accounts very effectively.
Only one other type of text survived from these ancient days, and it is even
less exciting: lists of words, copied over and over again by apprentice scribes as
training exercises. Even had a bored student wanted to write out some of his
poems instead of copy a bill of sale, he could not have done so. The earliest
Sumerian writing was a partial rather than a full script. Full script is a system of
material signs that can represent spoken language more or less completely. It can
therefore express everything people can say, including poetry. Partial script, on
the other hand, is a system of material signs that can represent only particular
types of information, belonging to a limited field of activity. Latin script, ancient
Egyptian hieroglyphics and Braille are full scripts. You can use them to write tax
registers, love poems, history books, food recipes and business law. In contrast,
the earliest Sumerian script, like modern mathematical symbols and musical
notation, are partial scripts. You can use mathematical script to make
calculations, but you cannot use it to write love poems.
20. A man holding a quipu, as depicted in a Spanish manuscript
following the fall of the Inca Empire.
It didn’t disturb the Sumerians that their script was ill-suited for writing
poetry. They didn’t invent it in order to copy spoken language, but rather to do
things that spoken language failed at. There were some cultures, such as those of
the pre-Columbian Andes, which used only partial scripts throughout their entire
histories, unfazed by their scripts’ limitations and feeling no need for a full
version. Andean script was very different from its Sumerian counterpart. In fact,
it was so different that many people would argue it wasn’t a script at all. It was
not written on clay tablets or pieces of paper. Rather, it was written by tying
knots on colourful cords called quipus. Each quipu consisted of many cords of
different colours, made of wool or cotton. On each cord, several knots were tied
in different places. A single quipu could contain hundreds of cords and
thousands of knots. By combining different knots on different cords with
different colours, it was possible to record large amounts of mathematical data
relating to, for example, tax collection and property ownership.2
For hundreds, perhaps thousands of years, quipus were essential to the
business of cities, kingdoms and empires.3 They reached their full potential
under the Inca Empire, which ruled 10–12 million people and covered today’s
Peru, Ecuador and Bolivia, as well as chunks of Chile, Argentina and Colombia.
Thanks to quipus, the Incas could save and process large amounts of data,
without which they would not have been able to maintain the complex
administrative machinery that an empire of that size requires.
In fact, quipus were so effective and accurate that in the early years
following the Spanish conquest of South America, the Spaniards themselves
employed quipus in the work of administering their new empire. The problem
was that the Spaniards did not themselves know how to record and read quipus,
making them dependent on local professionals. The continent’s new rulers
realised that this placed them in a tenuous position – the native quipu experts
could easily mislead and cheat their overlords. So once Spain’s dominion was
more firmly established, quipus were phased out and the new empire’s records
were kept entirely in Latin script and numerals. Very few quipus survived the
Spanish occupation, and most of those remaining are undecipherable, since,
unfortunately, the art of reading quipus has been lost.
