Sapiens and Homo Deus

by Yuval Noah Harari

  One groundbreaking experiment was conducted by Daniel Kahneman, who won the 2002 Nobel Prize in Economics. Kahneman asked a group of volunteers to join a three-part experiment. In the ‘short’ part of the experiment, the volunteers inserted one hand into a container filled with water at 14°C for one minute, which is unpleasant, bordering on painful. After sixty seconds they were told to take their hand out. In the ‘long’ part of the experiment, volunteers placed their other hand in a different water container whose temperature was also 14°C. But after sixty seconds hot water was secretly introduced into the container, slightly increasing the temperature to 15°C. Thirty seconds later they were told to pull out their hand. Some volunteers did the ‘short’ part first, while others began with the ‘long’ part. In either case, exactly seven minutes after both parts were over came the third and most important part of the experiment. The volunteers were told they must repeat one of the two parts; and it was up to them to choose which. Fully 80 per cent preferred to repeat the ‘long’ experiment, remembering it as less painful.

  This cold-water experiment is so simple, yet its implications shake the core of the liberal world view. It exposes the existence of at least two different selves within us: the experiencing self and the narrating self. The experiencing self is our moment-to-moment consciousness. For the experiencing self, it’s obvious that the ‘long’ part of the cold-water experiment was worse. First you experience water at 14°C for sixty seconds, which is every bit as disagreeable as what you experience in the ‘short’ part, and then you must endure another thirty seconds of water at 15°C, which is marginally less bad, but still far from pleasant. For the experiencing self, it is impossible that adding a slightly unpleasant experience to a very unpleasant experience will make the entire episode more appealing.

  However, the experiencing self remembers nothing. It tells no stories and is seldom consulted when it comes to big decisions. Retrieving memories, telling stories and making major decisions are all the monopoly of a very different entity inside us: the narrating self. The narrating self is akin to Gazzaniga’s left-brain interpreter. It is forever busy spinning yarns about the past and making plans for the future. Like every journalist, poet and politician, the narrating self takes many short cuts. It doesn’t narrate everything, and usually weaves the story using only peak moments and end results. The value of the whole experience is determined by averaging peaks with ends. For example, in evaluating the short part of the cold-water experiment the narrating self calculates the average between the worst part (the water was very cold) and the last moment (the water was still very cold) and concludes that ‘the water was very cold’. The narrating self does the same thing with the long part of the experiment. It finds the average between the worst part (the water was very cold) and the last moment (the water was not quite so cold) and concludes that ‘the water was somewhat warmer’. Crucially, the narrating self is duration-blind, giving no importance to the differing lengths of the two parts. So when it has a choice between the two, it prefers to repeat the long part, the one in which ‘the water was somewhat warmer’.

  Every time the narrating self evaluates our experiences, it discounts their duration and adopts the ‘peak-end rule’ – it remembers only the peak moment and the end moment, and assesses the whole experience according to their average. This has far-reaching impact on all our practical decisions. Kahneman began investigating the experiencing self and the narrating self in the early 1990s when, together with Donald Redelmeier of the University of Toronto, he studied colonoscopy patients. In colonoscopy tests a tiny camera is inserted into the intestines through the anus in order to diagnose various bowel diseases. It is not a pleasant experience. Doctors wanted to know how to perform this procedure in the least painful way. Should they hasten the colonoscopy and cause patients more distress for a shorter duration, or should they work more slowly and carefully?

  To answer this query, Kahneman and Redelmeier asked 154 patients to report their pain level at one-minute intervals during the colonoscopy. They used a scale of 0 to 10, where 0 meant no pain at all and 10 meant intolerable pain. After the colonoscopy was over patients were asked to rank the test’s ‘overall pain level’, also on a scale of 0 to 10. We might have expected the overall ranking to reflect the accumulation of minute-by-minute reports, that is the longer the colonoscopy lasted, and the more pain the patient experienced, the higher the overall pain level. But the actual results were different.

  Just as in the cold-water experiment, the overall pain level neglected duration and instead reflected only the peak-end rule. One colonoscopy lasted eight minutes, at the worst moment the patient reported a level 8 pain, and in the last minute he reported a level 7 pain. After the test was over this patient ranked his overall pain level at 7.5. Another colonoscopy lasted twenty-four minutes. This time too peak pain was at level 8, but in the very last minute of the test, the patient reported a level 1 pain. This patient ranked his overall pain level at only 4.5. The fact that his colonoscopy lasted three times longer, and that he consequently suffered far more pain on aggregate, did not affect his memory at all. The narrating self doesn’t aggregate experiences – it averages them.

  So what do the patients prefer: to have a short and sharp colonoscopy, or a long and careful one? There isn’t a single answer to this question, because the patient has at least two different selves and they have different interests. If you ask the experiencing self, it would probably choose a short colonoscopy. But if you ask the narrating self, it would prefer a long colonoscopy because it remembers only the average between the worst moment and the last moment. Indeed, from the viewpoint of the narrating self, the doctor should add a few completely superfluous minutes of dull aches at the very end of the test, because it would make the entire memory far less traumatic.15

  Paediatricians know this trick well. So do veterinarians. Many keep in their clinics jars full of treats, and hand a few to the kids (or dogs) after giving them a painful injection or an unpleasant medical examination. When the narrating self remembers the visit to the doctor, ten seconds of pleasure at the end of the visit will erase many minutes of anxiety and pain.

  Evolution discovered this trick aeons before the paediatricians. Given the unbearable torments that many women undergo during childbirth, one might think that after going through it once no sane woman would ever agree to do so again. However, at the end of labour and in the following days the hormonal system secretes cortisol and beta-endorphins, which reduce the pain and create a feeling of relief and sometimes even of elation. Moreover, the growing love towards the baby and the acclaim from friends, family members, religious dogmas and nationalist propaganda, conspire to transform childbirth from a trauma into a positive memory.

  40. An iconic image of the Virgin Mary holding baby Jesus. In most cultures, childbirth is portrayed as a wonderful experience rather than as a trauma.

  40.Virgin and Child, Sassoferrato, Il (Giovanni Battista Salvi) (1609–85), Musee Bonnat, Bayonne, France © Bridgeman Images.

  One study conducted at the Rabin Medical Center in Tel Aviv demonstrated that the memory of labour reflected mainly the peak and end points, while the overall duration had almost no impact at all.16 In another research project, 2,428 Swedish women were asked to recount their memories of labour two months after giving birth. Ninety per cent reported that the experience was either positive or very positive. They didn’t necessarily forget the pain – 28.5 per cent described it as the worst pain imaginable – yet it did not prevent them from evaluating the experience as positive. The narrating self goes over our experiences with a sharp pair of scissors and a thick black marker. It censors at least some moments of horror, and files in the archive a story with a happy ending.17

  Most of our critical life choices – of partners, careers, residences and holidays – are taken by our narrating self. Suppose you can choose between two potential holidays. You can go to Jamestown, Virginia, and visit the historic colonial town where the first English settleme
nt on mainland North America was founded in 1607. Alternatively, you can realise your number one dream vacation, whether it is trekking in Alaska, sunbathing in Florida or indulging in an unbridled bacchanalia of sex, drugs and gambling in Las Vegas. But there is a caveat: if you choose your dream vacation, then just before you board the plane home, you must take a pill that will obliterate all your memories of that vacation. What happened in Vegas will forever remain in Vegas. Which holiday would you choose? Most people would opt for colonial Jamestown, because most people give their credit card to the narrating self, which cares only about stories and has zero interest in even the most mind-blowing experiences if it cannot remember them.

  Truth be told, the experiencing self and the narrating self are not completely separate entities but are closely intertwined. The narrating self uses our experiences as important (but not exclusive) raw materials for its stories. These stories, in turn, shape what the experiencing self actually feels. We experience hunger differently when we fast during Ramadan, when we fast in preparation for a medical examination, and when we don’t eat because we have no money. The different meanings ascribed to our hunger by the narrating self create very different actual experiences.

  Furthermore, the experiencing self is often strong enough to sabotage the best-laid plans of the narrating self. I might, for instance, make a New Year’s resolution to start a diet and go to the gym every day. Such grand decisions are the monopoly of the narrating self. But the following week when it’s gym time, the experiencing self takes over. I don’t feel like going to the gym, and instead I order pizza, sit on the sofa and turn on the TV.

  Nevertheless, most of us identify with our narrating self. When we say ‘I’, we mean the story in our head, not the onrushing stream of experiences we undergo. We identify with the inner system that takes the crazy chaos of life and spins out of it seemingly logical and consistent yarns. It doesn’t matter that the plot is full of lies and lacunas, and is rewritten again and again, so that today’s story flatly contradicts yesterday’s. The important thing is that we always retain the feeling that we have a single unchanging identity from birth to death (and perhaps even beyond). This gives rise to the questionable liberal belief that I am an individual, and that I possess a clear and consistent inner voice that provides meaning to the entire universe.18

  The Meaning of Life

  The narrating self is the star of Jorge Luis Borges’s story ‘A Problem’.19 The story concerns Don Quixote, the eponymous hero of Miguel Cervantes’s famous novel. Don Quixote creates for himself an imaginary world in which he is a legendary champion going forth to fight giants and save Lady Dulcinea del Toboso. In reality Don Quixote is Alonso Quixano, an elderly country gentleman; the noble Dulcinea is an uncouth farm girl from a nearby village; and the giants are windmills. What would happen, wonders Borges, if due to his belief in these fantasies, Don Quixote attacks and kills a real person? Borges asks a fundamental question about the human condition: what happens when the yarns spun by our narrating self cause grievous harm to ourselves or those around us? There are three main possibilities, says Borges.

  One option is that nothing much happens. Don Quixote will not be bothered at all by killing a real man. His delusions are so overpowering that he will not be able to recognise the difference between committing actual murder and dueling with the imaginary windmill giants. Another option is that once he takes a person’s life, Don Quixote will be so horrified that he will be shaken out of his delusions. This is akin to a young recruit who goes to war believing that it is good to die for one’s country, only to end up completely disillusioned by the realities of warfare.

  But there is a third option, much more complex and profound. As long as he fought imaginary giants, Don Quixote was just play-acting. However once he actually kills someone, he will cling to his fantasies for all he is worth, because only they give meaning to his tragic misdeed. Paradoxically, the more sacrifices we make for an imaginary story, the more tenaciously we hold on to it, because we desperately want to give meaning to these sacrifices and to the suffering we have caused.

  In politics this is known as the ‘Our Boys Didn’t Die in Vain’ syndrome. In 1915 Italy entered the First World War on the side of the Entente powers. Italy’s declared aim was to ‘liberate’ Trento and Trieste – two ‘Italian’ territories that the Austro-Hungarian Empire held ‘unjustly’. Italian politicians gave fiery speeches in parliament, vowing historical redress and promising a return to the glories of ancient Rome. Hundreds of thousands of Italian recruits went to the front shouting, ‘For Trento and Trieste!’ They thought it would be a walkover.

  It was anything but. The Austro-Hungarian army held a strong defensive line along the Isonzo River. The Italians hurled themselves against it in eleven gory battles, gaining a few miles at most and never securing a breakthrough. In the first battle they lost 15,000 men. In the second battle they lost 40,000 men. In the third battle they lost 60,000. So it continued for more than two dreadful years until the eleventh engagement. Then the Austrians finally counter-attacked, and in the twelfth battle, known as the battle of Caporreto, they soundly defeated the Italians and pushed them back almost to the gates of Venice. The glorious adventure became a bloodbath. By the end of the war almost 700,000 Italian soldiers were killed and more than a million were wounded.20

  After losing the first Isonzo battle Italian politicians had two choices. They could have admitted their mistake and offered to sign a peace treaty. Austria–Hungary had no claims against Italy and would have been delighted to make a peace treaty because it was busy fighting for its survival against the much stronger Russians. Yet how could the politicians go to the parents, wives and children of 15,000 dead Italian soldiers and tell them: ‘Sorry, there has been a mistake. We hope you won’t take it too hard, but your Giovanni died in vain, and so did your Marco.’ Alternatively they could say: ‘Giovanni and Marco were heroes! They died so that Trieste would be Italian, and we will make sure they didn’t die in vain. We will go on fighting until victory is ours!’ Not surprisingly, the politicians preferred the second option. So they fought a second battle, and lost another 40,000 men. The politicians again decided it would be best to keep on fighting, because ‘our boys didn’t die in vain’.

  41. A few of the victims of the Isonzo battles. Was their sacrifice in vain?

  41.© Bettmann/Corbis.

  Yet you cannot blame only the politicians. The masses also kept supporting the war. And when after the war Italy did not get all the territories it demanded, Italian democracy placed at its head Benito Mussolini and his fascists, who promised they would obtain a proper compensation for all the sacrifices the Italians had made. While it’s difficult for a politician to tell parents that their son died for no good reason, it is far more painful for parents to say this to themselves – and it is even harder for the victims. A crippled soldier who lost his legs would rather tell himself, ‘I sacrificed myself for the glory of the eternal Italian nation!’ than ‘I lost my legs because I was stupid enough to believe self-serving politicians.’ It is much easier to live with the fantasy, because the fantasy gives meaning to the suffering.

  Priests discovered this principle thousands of years ago. It underlies numerous religious ceremonies and commandments. If you want to make people believe in imaginary entities such as gods and nations, you should make them sacrifice something valuable. The more painful the sacrifice, the more convinced they will be of the existence of the imaginary recipient. A poor peasant sacrificing a valuable bull to Jupiter will become convinced that Jupiter really exists, otherwise how can he excuse his stupidity? The peasant will sacrifice another bull, and another, and another, just so he won’t have to admit that all the previous bulls were wasted. For exactly the same reason, if I have sacrificed a child to the glory of the Italian nation or my legs to the communist revolution, that’s usually enough to turn me into a zealous Italian nationalist or an enthusiastic communist. For if Italian national myths or communist propaganda are
a lie, then I will be forced to concede that my child’s death or my own paralysis have been completely pointless. Few people have the stomach to admit such a thing.

  The same logic is at work in the economic sphere too. In 1999 the government of Scotland decided to erect a new parliament building. According to the original plan the construction was expected to take two years and cost £40 million. In fact it took five years and cost £400 million. Every time the contractors encountered unforeseen difficulties and expenses, they went to the Scottish government and asked for more time and money. Every time this happened the government said to itself: ‘Well, we’ve already sunk tens of millions into this and we’ll be completely discredited if we stop now and end up with a partially built skeleton. Let’s authorise another £40 million.’ Several months later the same thing happened again, by which time the pressure to avoid ending up with an unfinished building was even greater. And a few months after that the story repeated itself, and so on until the actual cost was ten times the original estimate.

  Not only governments fall into this trap. Business corporations often sink millions into failed enterprises, while private individuals cling to dysfunctional marriages and dead-end jobs. Our narrating self would much prefer to continue suffering in the future, just so it won’t have to admit that our past suffering was devoid of all meaning. Eventually, if we want to come clean about past mistakes, our narrating self must invent some twist in the plot that will infuse these mistakes with meaning. For example, a pacifist war veteran may tell himself, ‘Yes, I’ve lost my legs because of a mistake. But thanks to this mistake I understand that war is hell, and from now onwards I will dedicate my life to fight for peace. So my injury did have some positive meaning after all: it taught me to value peace.’

  42. The Scottish Parliament building. Our sterling did not die in vain.