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Now you see it, now you don't: what optical illusions tell us about our brains

Illusions can offer insights into how the visual system processes images.

Maurits Escher: where do the staircases lead?

The human brain is a network of about 20 billion neurons – nerve cells – linked by several trillion connections. Not to mention glial cells, which scientists used to think were inactive scaffolding, but increasingly view as an essential part of how the brain works. Our brains give us movement, language, senses, memories, consciousness and personality. We know a lot more about the brain than we used to, but it still seems far too complicated for human understanding.

Fortunately, the brain contains many small networks of neurons that carry out some specific function: vision, hearing, movement. It makes sense to tackle these simple modules first. Moreover, we have good mathematical models of nerve cell behaviour. In 1952, Alan Hodgkin and Andrew Huxley wrote down the “Hodgkin-Huxley equations” for the transmission of a nerve impulse, which won them the 1963 Nobel Prize in Medicine. We also have effective techniques for understanding small networks’ components and how they are linked.

Many of these simple networks occur in the visual system. We used to think that the eye was like a camera, taking a “snapshot” of the outside world that was stored in the brain like a photo stuck in an album. It uses a lens to focus an image on to the retina at the back of the eye, which functions a bit like a roll of film – or, in today’s digital cameras, a charge-coupled device, storing an image pixel by pixel. But we now know that when the retina sends information to the brain’s visual cortex, the similarity to a camera ends.

Although we get a strong impression that what we are seeing is “out there” in front of us, what determines that perception resides inside our own heads. The brain decomposes images into simple pieces, works out what they are, “labels” them with that information, and reassembles them. When we see three sheep and two pigs in a field, we “know” which bits are sheep, which are pigs, and how many of each there are. If you try to program a computer to do that, you quickly realise how tricky the process is. Only very recently have computers been able to distinguish between faces, let alone sheep and pigs.

Probing the brain’s detailed activity is difficult. Rapid progress is being made, but it still takes a huge effort to get reliable information. But when science cannot observe something directly, it infers it, working indirectly. An effective way to infer how something functions is to see what it does when it goes wrong. It may be hard to understand a bridge while it stays up, but you can learn a lot about strength of materials when it collapses.

The visual system can “go wrong” in several interesting ways. Hallucinogenic drugs can change how neurons behave, producing dramatic images such as spinning spirals, which originate not in the eye, but in the brain. Some images even cause the brain to misinterpret what it’s seeing without outside help. We call them optical illusions.

One of the earliest was discovered in Renaissance Italy in the 16th century. Giambattista della Porta was the middle of three surviving sons of a wealthy merchant nobleman who became secretary to the Holy Roman emperor Charles V. The father was an intellectual, and Giambattista grew up in a house in Naples that hosted innumerable mathematicians, scientists, poets and musicians. He became an outstanding polymath, with publications on secret codes (including writing on the inside of eggshells), physiology, botany, agriculture, engineering, and much else. He wrote more than 20 plays.

Della Porta was particularly interested in the science of light. He made definitive improvements to the camera obscura, a device that projects an image of the outside world into a darkened room; he claimed to have invented the telescope before Galileo, and very likely did. His De refractione optices of 1593 contained the first report of a curious optical effect. He arranged two books so that one was visible to one eye only and the other to the other eye. Instead of seeing a combination of the two images, he perceived them alternately. He discovered that he could select either image at will by consciously switching his attention. This phenomenon is known today as binocular rivalry.

Two other distinct but related effects are impossible figures and visual illusions. In rivalry, each image appears unambiguous, but the eyes are shown conflicting images. In the other two phenomena, both eyes see the same image, but in one case it doesn’t make sense, and in the other it makes sense but is ambiguous.

Impossible figures at first sight seem to be entirely normal, but depict things that cannot exist – such as Roger Shepard’s 1990 drawing of an elephant in which everything above the knees makes sense, and everything below the knees makes sense, but the two regions do not fit together correctly. The Dutch artist Maurits Escher made frequent use of this kind of visual quirk.

In 1832, the Swiss crystallographer Louis Necker invented his “Necker cube” illusion, a skeletal cube that seems to switch its orientation repeatedly. An 1892 issue of the humorous German magazine Fliegende Blätter contains a picture with the caption “Which animals are most like each other?” and the answer “Rabbit and duck”. In a 1915 issue of the American magazine Puck, the cartoonist Ely William Hill published “My wife and my mother-in-law”, based on an 1888 German postcard. The image can be seen either as a young lady looking back over her shoulder, or as an elderly woman facing forwards. Several of Salvador Dalí’s paintings include illusions; especially Slave Market With the Apparition of the Invisible Bust of Voltaire, where a number of figures and everyday objects, carefully arranged, combine to give the impression of the French writer’s face.

Illusions offer insights into how the visual system processes images. The first few stages are fairly well understood. The top layer in the visual cortex detects edges of objects and the direction in which they are pointing. This information is passed to lower layers, which detect places where the direction suddenly changes, such as corners. Eventually some region in the cortex detects that you are looking at a human face and that it belongs to Aunt Matilda. Other parts of the brain are alerted, and you belatedly remember that tomorrow is her birthday and hurry off to buy a present.

These things don’t happen by magic. They have a very definite rationale, and that’s where the mathematics comes in. The top layer of the visual cortex contains innumerable tiny stacks of nerve cells. Each stack is like a pile of pancakes, and each pancake is a network of neurons that is sensitive to edges that point in one specific direction: one o’clock, two o’clock and so on.

For simplicity, call this network a cell; it does no harm to think of it as a single neuron. Roughly speaking, the cell at the top of the stack senses edges at the one o’clock position, the next one down corresponds to the two o’clock angle, and so on. If one cell receives a suitable input signal, it “fires”, telling all the other cells in its stack: “I’ve seen a boundary in the five o’clock direction.” However, another cell in the same stack might disagree, claiming the direction is at seven o’clock. How to resolve this conflict?

Neurons are linked by two kinds of connection, excitatory and inhibitory. If a neuron activates an excitatory connection, those at the other end of it are more likely to fire themselves. An inhibitory connection makes them less likely to fire. The cortex uses inhibitory connections to reach a definite decision. When a cell fires, it sends inhibitory signals to all of the other cells in its stack. These signals compete for attention. If the five o’clock signal is stronger than the seven o’clock one, for instance, the seven o’clock one gets shut down. The cells in effect “vote” on which direction they are detecting and the winner takes all.

Many neuroscientists think that something very similar is going on in visual illusions and rivalry. Think of the duck and rabbit with two possible interpretations. Hugh R Wilson, a neuroscientist at the Centre for Vision Research at York University, Toronto, proposed the simplest model, one stack with just two cells. Rodica Curtu, a mathematician at the University of Iowa, John Rinzel, a biomathematician then at the National Institutes of Health, and several other scientists have analysed this model in more detail. The basic idea is that one cell fires if the picture looks like a duck, the other if it resembles a rabbit. Because of the inhibitory connections, the winner should take all. Except that, in this illusion, it doesn’t quite work, because the two choices are equally plausible. That’s what makes it an illusion. So both cells want to fire. But they can’t, because of those inhibitory connections. Yet neither can they both remain quiescent, because the incoming signals encourage them to fire.

One possibility is that random signals coming from elsewhere in the brain might introduce a bias of perception, so that one cell still wins. However, the mathematical model predicts that, even without such bias, the signals in both cells should oscillate from active to inactive and back again, each becoming active when the other is not. It’s as if the network is dithering: the two cells take turns to fire and the network perceives the image as a duck, then as a rabbit, and keeps switching from one to the other. Which is what happens in reality.

Generalising from this observation, Wilson proposed a similar type of network that can model decision-making in the brain – which political party to support, for instance. But now the network consists of several stacks. Maybe one stack represents immigration policy, another unemployment, a third financial regulation, and so on. Each stack consists of cells that “recognise” a distinct policy feature. So the financial regulation stack has cells that recognise state regulation by law, self-regulation by the industry, or free-market economics.

The overall political stance of any given political party is a choice of one cell from each stack – one policy decision on each issue. Each prospective voter has his or her preferences, and these might not match those of any particular party. If these choices are used as inputs to the network, it will identify the party that most closely fits what the voter prefers. That decision can then be passed to other areas of the brain. Some voters may find themselves in a state akin to a visual illusion, vacillating between Labour and Liberal Democrat, or Conservative and Ukip.

This idea is speculative and it is not intended to be a literal description of how we decide whom to vote for. It is a schematic outline of something more complex, involving many regions of the brain. However, it provides a simple and flexible model for decision-making by a neural network, and in particular it shows that simple networks can do the job quite well. Martin Golubitsky of the Mathematical Biosciences Institute at Ohio State University and Casey O Diekman of the University of Michigan wondered whether Wilson’s networks could be used to model more complex examples of rivalry and illusions. Crucially, the resulting models allow specific predictions about experiments that have not yet been performed, making the whole idea scientifically testable.

The first success of this approach helped to explain an experiment that had already been carried out, with puzzling results. When the brain reassembles the separate bits of an image, it is said to “bind” these pieces. Rivalry provides evidence that binding occurs, by making it go wrong. In a rivalry experiment carried out in 2006 by S W Hong and S K Shevell, the subject’s left eye is shown a horizontal grid of grey and pink lines while the right eye sees a vertical grid of grey and green lines. Many subjects perceive an alternation between the images, just as della Porta did with his books. But some see two different images alternating: pink and green vertical lines, and pink and green horizontal lines – images shown to neither eye. This effect is called colour misbinding; it tells us that the reassembly process has matched colour to grid direction incorrectly. It is as if della Porta had ended up seeing another book altogether.

Golubitsky and Diekman studied the simplest Wilson network corresponding to this experiment. It has two stacks: one for colour, one for grid direction. Each stack has two cells. In the “colour” stack one cell detects pink and the other green; in the “orientation” stack one cell detects vertical and the other horizontal. As usual, there are inhibitory connections within each stack to ensure a winner-takes-all decision.

Following Wilson’s general scheme, they also added excitatory connections between cells in distinct stacks, representing the combinations of colour and direction that occur in the two “learned” images – those actually presented to the two eyes. Then they used recent mathematical techniques to list the patterns that arise in such a network. They found two types of oscillatory pattern. One corresponds to alternation between the two learned images. The other corresponds precisely to alternation between the two images seen in colour misbinding.

Colour misbinding is therefore a natural feature of the dynamics of Wilson networks. Although the network is “set up” to detect the two learned images, its structure produces an unexpected side effect: two images that were not learned. The rivalry experiment reveals hints of the brain’s hidden wiring. The same techniques apply to many other experiments, including some that have not yet been performed. They lead to very specific predictions, including more circumstances in which subjects will observe patterns that were not presented to either eye.

Similar models also apply to illusions. However, the excitatory connections cannot be determined by the images shown to the two eyes, because both eyes see the same image. One suggestion is that the connections may be determined by what your visual system already “knows” about real objects.

Take the celebrated moving illusion called “the spinning dancer”. Some observers see the solid silhouette of a dancer spinning anticlockwise, others clockwise. Sometimes, the direction of spin seems to switch suddenly.

We know that the top half of a spinning dancer can spin either clockwise or anticlockwise. Ditto for the bottom half. In principle, if the top half spins one way but the bottom half spins the other way, you would see the same silhouette, as if both were moving together. When people are shown “the spinning dancer”, no one sees the halves moving independently. If the top half spins clockwise, so does the bottom half.

Why do our brains do this? We can model that information using a series of stacks that correspond to different parts of the dancer’s body. The brain’s prior knowledge sets up a set of excitatory connections between all cells that sense clockwise motion, and another set of excitatory connections between all “anticlockwise” cells. We can also add inhibitory connections between the “clockwise” and the “anticlockwise” cells. These connections collectively tell the network that all parts of the object being perceived must spin in the same direction at any instant. Our brains don’t allow for a “half and half” interpretation.

When we analyse this network mathematically, it turns out that the cells switch repeatedly between a state in which all clockwise cells are firing but the anticlockwise ones are quiescent, and a state in which all anticlockwise cells are firing but the clockwise ones are quiescent. The upshot is that we perceive the whole figure of the dancer switching directions. Similar networks provide sensible models for many other illusions, including some in which there are three different inputs.

These models provide a common framework for both rivalry and illusion, and they unify many experiments, explain otherwise puzzling results and make new predictions that can be tested. They also tell us that in principle the brain can carry out some apparently complex tasks using simple networks. (What it does in practice is probably different in detail, but could well follow the same general lines.)

This could help make sense of a real brain, as new experiments improve our ability to observe its “wiring diagram”. It might not be as ambitious as trying to model the whole thing on a computer, but modesty can be a virtue. Since simple networks behave in strange and unexpected ways, what incomprehensible quirks might a complicated network have?

Perhaps Dalí, and Escher, and the spinning dancer can help us find out. 

Ian Stewart is Emeritus Professor of Mathematics and Digital Media Fellow at the University of Warwick

MOISES SAMAN/MAGNUM
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The price of a life

In 2014, Islamic State fighters murdered thousands of Yazidis and kidnapped many others, mostly women and children. Their desperate relatives are now trying to buy them back.

1. Taken

On the morning of 3 August 2014, a 58-year-old chef known as Abu Majed faced the most agonising decision of his life. Earlier that summer, Islamic State (IS) fighters had overrun vast areas of northern Iraq. Now, they were closing in on the villages and towns that surround Mount Sinjar, a jagged ridge of rock that rises abruptly from the flatlands and extends for tens of kilometres towards the Syrian border. Abu Majed’s village, Khanasur, had few defences and would fall to the militants. How should he protect his family?

A popular, humorous man, Abu Majed learned to cook in Baghdad in the 1970s before returning to Khanasur to open his gazino, an outdoor restaurant where young people liked to gather for grilled meat, beer and whisky among trees strung with fairy lights. He had five children and was fiercely proud of all of them. They were at the top of their classes at school and his two eldest wanted to study medicine. To Abu Majed – who, like almost everyone else in Khanasur, had descended from a long line of subsistence farmers – these ambitions were remarkable.

Abu Majed’s restaurant had been a haven during many turbulent years in Iraq. He kept it open through the repressive reign of Saddam Hussein and during the violence that followed the US-led invasion of Iraq in 2003. But the threat now posed by the jihadists was greater than anything that had come before – especially because the villagers of Khanasur are Yazidis, an isolated and marginalised religious minority that has lived for centuries in north-west Iraq.

Having heard reports of the jihadists’ brutality elsewhere, Abu Majed was certain that IS’s main target would be the Yazidi men. The best option was for his family to split. After sending his wife and four youngest children – then aged between eight and 15 – to shelter with another family in the village, he walked with his eldest son towards Mount Sinjar. Abu Majed was still on the ascent when his phone rang. On the screen, he saw his daughter’s number. “They’ve captured us,” she whispered.

Abu Majed decided to turn back to try to rescue them, accepting that it would probably be a suicide mission. When he and his son arrived the following day in Khanasur, it was deserted. Devastated and distraught, they returned to Mount Sinjar, joining tens of thousands of fellow Yazidis stranded on the summit with no food, clean water or protection from the fierce sun.

They were trapped. The mountain was surrounded by IS fighters who had rampaged through the nearby villages, slaughtering thousands of Yazidis and taking thousands more hostage. Sometimes they gave people the choice between converting to Islam and death; some converted and were murdered anyway.

A few days into the siege, Iraqi and then American, British and Australian military aircraft began dropping food parcels and water on to the mountain. Often they unloaded from a great height to avoid coming under fire from IS militants and the bottles would burst on impact, water seeping into the yellow dust. When the helicopters could fly low enough, dozens of people struggled to climb aboard so that they could be airlifted to safety – but few made it off the mountain that way. Abu Majed and his son saw old people and infants succumb to starvation. “People were saying, ‘We wish we would die here. Maybe they [IS] could just strike us with chemical weapons.’”

On 7 August, four days after Abu Majed fled to Mount Sinjar, the US launched an aerial campaign to break the siege. At the same time, Syrian Kurdish forces known as the People’s Protection Units (YPG) forced a way through IS lines and opened up a humanitarian corridor a week later. On 14 August, a ragged column of people walked down the mountain and across the sun-bleached landscape into Syria. At great risk, Abu Majed and his son slipped back into Khanasur to salvage a few precious family photographs. Then they walked for 14 hours to the Syrian border. There, they hitched a lift in another family’s car to reach Kurdistan, a semi-autonomous region in northern Iraq.

In March, I met Abu Majed in Dohuk, a city of 350,000 people in the fertile mountains of western Kurdistan, where an uneasy peace prevails. At checkpoints evenly spaced along the city’s main tributaries, grim-faced soldiers scrutinise passing drivers with unsettling diligence. There is a feeling of claustrophobia: the memory of IS’s advance is still so recent and the front lines are close.

Abu Majed is short and bald, with a wide moustache and a narrow, drawn face. He cried several times as he told me his story when we met in an empty café, and each time he would stare down at his untouched tea until the tears stopped. Then he would quietly apologise. He lives alone in a camp for internally displaced people (IDPs) in the nearby town of Shariya and cooks for a battalion of Yazidi soldiers. The work is unpaid but it is a distraction from his sense of loss and loneliness. His eldest son, who fled with him to Mount Sinjar, is a boarder at a pharmacy college. The rest of his family are hostages.

Abu Majed last heard from his wife and three youngest children in October 2015, when they borrowed a smuggled phone from a fellow hostage for a few minutes – just long enough to tell him they were still alive and in Tal Afar, an IS-controlled city in north-west Iraq. He had not heard anything from his eldest daughter, Majida, since March 2015. Then, a few weeks before we met, he received a telephone call from a people smuggler.

 

2. The Yazidis

The United Nations estimates that at least 5,000 Yazidis were murdered in August 2014 and between 5,000 and 7,000 were taken hostage. In the months that followed, news began to spread – through hushed phone calls from hostages and the testimony of escapees – of IS’s systematic violence against its Yazidi prisoners. The men and older boys were separated from their relatives and usually killed. Women and children were kept in cramped and filthy conditions, in prisons and old school buildings, where they were deprived of food and water and forced to convert to Islam. Unmarried or younger women and girls were sold into sexual or domestic slavery or given as gifts to fighters. Boys, some as young as eight, were sent to training camps to become jihadists. This January, the UN estimated that 3,500 Yazidis were still in IS captivity.

The IS fighters who brutalise Yazidi boys in training camps or rape and humiliate female slaves have a brutal sense of religious righteousness. A pamphlet released by the group in 2014 instructs that: “It is permissible to buy, sell, or give as a gift female captives and slaves, for they are merely property, which can be disposed of as long as that doesn’t cause [the Muslim community] any harm or damage.” It specifies that it is “permissible” to have “intercourse with the female slave who hasn’t reached puberty”. Should a woman attempt to escape, she should be punished in a manner that “deters others from escaping”.

In March, the US joined the European Parliament in ruling that IS’s crimes against Yazidis constituted genocide. The Yazidis use the word ferman to refer to the atrocity (it is an Ottoman term meaning “royal decree”) and say that throughout their almost 7,000-year history, they have survived scores of attempts to wipe out their people. In 2007, they were the victims of the second most deadly terrorist attack in modern history – after 9/11 – when Sunni militants killed more than 500 people in simultaneous bomb attacks on two Yazidi villages near Sinjar. They describe the events of
August 2014 as the 73rd ferman.

There are perhaps half a million Yazidis, most of whom live in Iraq, though there are smaller communities in Armenia, Georgia, Germany, Russia and Syria. They have historically remained cut off from the rest of society. This is partly because of long-standing discrimination. Under Saddam Hussein, the Yazidis of Sinjar were banned from teaching their own language – Kurmanji, or Northern Kurdish – and in the 1970s, they were displaced from their ancestral farmlands and homes on the mountain and forced into “collective villages”. (Abu Majed’s village of Khanasur is one such settlement.)

Their isolation is also partly through choice. You can only become a Yazidi by birth and Yazidis cannot marry non-believers, or even outside their own caste or sect. They are discouraged from sharing their religious beliefs, which are largely transmitted orally, with outsiders.

One morning, I visited Lalish, the holiest site in the Yazidi religion, to which all followers must make a pilgrimage at least once in their lives. The shrines are built on a hillside, about 30 kilometres south-east of Dohuk. Visitors and pilgrims take off their shoes in the car park, because every stone in Lalish is sacred. There were a few families and young men with selfie sticks but before the ferman Lalish would have been much busier on a fine spring day. The grey stone shrines, with distinctive conical rooftops, are dedicated to Sheikh Adi and his companions. Sheikh Adi was an 11th-century prophet – or, perhaps, a god – who organised Yazidi society into castes: the laymen, called the murids, and their assigned spiritual guides, known as the sheikhs and pirs.

In a courtyard, I met Sheikh Hussein, whose family has looked after Lalish for generations. He has a thick beard and was wearing a red-and-white keffiyeh knotted into a turban and a baggy khaki jacket with matching Kurdish pantaloon trousers. He chain-smoked slim cigarettes. He told me that he believed the ferman was a punishment from God, because Yazidis had grown distant from him. “What happened to Yazidis was because people don’t remember God, but now people remember God,” he said.

The Yazidi God, Melek Taus, takes the form of a peacock. Parallels between Melek Taus and Azazel, or Lucifer – the angel who, according to Jewish, Christian and Islamic tradition, rebelled against God – have contributed to the belief that Yazidis are devil-
worshippers, a slur that has been used throughout history to justify their persecution. Yazidis do not worship the devil, although unlike Christians, Muslims or Jews, they do not believe that God is purely good. If God is omnipotent, they argue, surely he could defeat the devil? The Yazidi God can be angry and cruel.

 

3. The smugglers

When the chef Abu Majed was contacted by the people smuggler, he was initially suspicious. The smuggler was an Arab Muslim from the town of Sinjar, to the south of the mountain, and IS’s massacres have deepened many Yazidis’ mistrust of their Muslim neighbours. Yet his ethnicity and religion were advantageous: the smuggler could move across IS territory without attracting too much attention and could speak to jihadists in their own language, Arabic.

The smuggler told Abu Majed that his eldest daughter was being forced to work as a nurse in a hospital in Raqqa, the IS stronghold in Syria. He offered details that seemed to fit with the little information Abu Majed had gleaned from speaking to former hostages. The smuggler said that for $18,000 he could buy his daughter from IS and bring her home. Abu Majed has decided to trust him. He has no money but told me that when he receives confirmation from the smuggler that the deal with IS has been agreed, he will start “begging” for funds from his relatives, friends, NGOs – anyone who could help him.

With few other options, despairing Yazidis have resorted to dangerous and expensive ways of rescuing their loved ones from IS captivity. Some, such as Abu Majed, try to scrape together tens of thousands of dollars to pay middlemen – many of them Arab Muslims – who promise to buy slaves from IS fighters in order to liberate them. 

Others have placed their faith in another class of hostage smuggler – often fellow Yazidis – who say that they have devised elaborate schemes for rescuing slaves and sneaking them out of the jihadists’ territory. Their networks extend deep into IS-controlled Iraq and Syria but the operations are planned in Iraqi Kurdistan, where tens of thousands of Yazidis are sheltering in sprawling camps.

Sinjar district is nominally part of Iraq but many Kurds believe that it should be part of Iraqi Kurdistan. The Kurdish regional government (KRG) has sought to extend its influence over the area. In November 2014, the KRG set up its “Office of Kidnapped Affairs” in Dohuk to maintain records of missing people, to ensure that survivors receive assistance and to organise hostage rescues. One afternoon, I arrived at the pink villa where the office is based to meet its director, Hussein al-Qaidi, a Yazidi former NGO worker and meat trader.

Al-Qaidi told me that 2,426 Yazidi hostages have been liberated since August 2014, including 1,204 children and 895 women. He said that more than 1,000 of them had been rescued directly by the office, which runs a network of people smugglers able to work within IS territory. A few Yazidis had escaped without help and in the remainder of cases hostages’ families had independently paid a smuggler to bring their relatives home. In these instances, the Office of Kidnapped Affairs refunds the money.

Al-Qaidi would not detail how rescue missions are conducted, saying that this would threaten future operations. Most of the families I spoke to believed that they were making payments to IS to free their loved ones but al-Qaidi insisted that his office never deals with IS operatives directly. “If you believe this money strengthens Da’esh, it’s not true. It does not go to Da’esh fighters,” he said, using the Arabic acronym for IS.

Al-Qaidi said that the Yazidi hostage crisis had created a perverse trade and a group of “war businessmen” who were pushing up the price of smuggling missions. The KRG is the office’s sole funder and its finances are in a desperate state because of the low oil price, the cost of the war against IS and monetary disputes with the Iraqi government. KRG officials and front-line Kurdish fighters – the peshmerga, or “those who face death” – have not been paid for months. Three families I spoke to, who are internally displaced and yet had somehow raised tens of thousands of dollars to pay smugglers, said that they were still waiting for refunds from the office. The smugglers told me that, for months, no government repayments had been made.

When I asked al-Qaidi what he would do if his office could no longer afford rescues, he said that he had a “plan B”, which he could not divulge. He did say, however, that his office was about to make a big announcement. He was working on a rescue mission to save 19 Yazidi hostages and if I called the next day, he might tell me more.
The following afternoon, I visited a Yazidi couple who have become a crucial part of the smuggling chain and sometimes work as volunteers for al-Qaidi’s office. They live in an apartment in an upmarket gated complex in Dohuk. Khaleel al-Dakhi, 38, is a former lawyer, tall and slim with a cool, confident demeanour.

Moments after we met, he held up his smartphone to display the photograph of a beautiful young woman wearing a tight, red T-shirt, with long, fair hair that she had flicked over one shoulder. He waited for a moment, seemingly enjoying my confusion. Then he told me that she was a Yazidi sex slave who had been put on sale for $11,000.

The photo was sent to al-Dakhi by a Yazidi friend who was posing online as an IS fighter in order to buy and liberate hostages. The friend had obtained a password for an internet chat room through which Yazidi slaves are traded. He forwards information on to al-Dakhi, who keeps a record of where women are being held and by whom.

Al-Dakhi and his wife, Ameena Saeed Hasan, are from the same village as Abu Majed but were already living in Dohuk when IS invaded Khanasur. Hasan had worked as an MP in Iraq’s national parliament until just weeks before the Sinjar crisis. In late 2014, her phone rang incessantly as IS hostages called her to plead for help. At first, she focused on gathering information on where hostages were being kept and how they were being treated, which she passed on to the Iraqi government. Then, she realised, “The government didn’t do anything.”

Using Hasan’s political connections and al-Dakhi’s business ones, they were able to mobilise a network of sympathetic Arab Muslims living in IS-controlled parts of Iraq to help them carry out rescues. They, too, were reluctant to discuss their techniques in detail but said in general hostage smuggling works like this: first, the hostage will provide Hasan or al-Dakhi with precise details of their location and their captor’s routines; then, the couple will co-ordinate with their smuggling network to locate a nearby safe house to which the hostage can flee and from where a smuggler can collect them. The hostage will often be passed between several different smugglers, chosen for their ability to blend into the community, and kept in a number of safe houses until they can travel to the IS border. Al-Dakhi liaises with the peshmerga on the front-line checkpoints so that the escapees are allowed into Kurdistan.

He often drives to the border, or even into the militants’ territory, despite the danger. When the women first see him, they sometimes rip off their headscarves, or kneel to kiss the ground, or break into a run. “They’ve been through all these terrible situations. They have suffered so much and in those moments they can’t believe they’ve made it,” al-Dakhi told me.

He is adamant that no money goes to IS. “We don’t buy hostages, we steal them,” he said. He estimates that he and his wife have rescued over 100 women and children, but they say that it is becoming ever harder to carry out a successful mission. IS has split up many groups of hostages. Increasingly the women are on their own and do not have access to a phone. Smugglers are demanding higher payments because of the rising danger. Six smugglers in al-Dakhi’s network have been killed. On one occasion, an IS fighter pretended on the phone to be a young Yazidi boy and then murdered the smuggler sent to rescue him. Another time, a smuggler was killed by a militant who disguised himself as a female hostage by wearing a black niqab.

 

4. Freedom

I contacted the Office of Kidnapped Affairs several times to ask if the rescue of the 19 Yazidis had been successful and each time was asked to call back. Then, I chanced upon the man who brought the hostages home: Abdallah Sherim, a 41-year-old Yazidi who felt compelled to help with rescues after 56 members of his extended family were kidnapped. I met him near Dohuk, in his brightly painted house on a small hill that overlooks Khanke IDP camp, where rows of blue-and-white tarpaulin tents are pitched close together in the churned-up roadside mud.

Sherim used to work as a trader between Sinjar and Aleppo in Syria. When his terrified relatives began to call him from captivity, he contacted his former business associates, who helped him find Syrians he could trust to assist him in carrying out rescue missions. He claimed to have liberated more than 200 Yazidis, including 24 members of his family. He showed me photographs of two nephews he had smuggled home a year earlier. They had since been resettled in Germany and had sent him snaps in their new football kit.

As we spoke, one of his sons turned up the volume on the TV. It was showing Nuce Ezidixan, a Yazidi news hour that is broadcast daily. Just as I was about to ask him to turn the volume down, I saw on the screen al-Qaidi from the kidnapping office – and then Sherim. They were posing next to the 19 liberated hostages: five women and 14 children. Al-Qaidi did not mention on the television, as Sherim later did, that nine of the smugglers involved in the mission had been captured. Nor did he mention the $6,500 per person the rescue had cost, money the families had raised themselves.

One of the 19 hostages rescued by Sherim’s network and then paraded on Yazidi TV was the 25-year-old Jehan (she asked that I did not use her full name). She is tall and broad-shouldered, with a deep, hoarse voice, and was wearing a long, flowery dress and a threadbare brown headscarf. Her hands were tattooed with the words ya allah – “O, God” – over and over. Her name ran up her right forearm in crude Roman capitals and on that hand was also written, el-hurriya, in Arabic script: “freedom”. All the female hostages had inked that same word on to one another’s hands but when her friend had tattooed her arm, six or seven months earlier, Jehan could not imagine what it would feel like to be free.

I spoke to her in the Rwanga IDP camp in western Kurdistan, where she was staying with the uncle who had paid $6,500 for her release. The camp houses as many as 15,500 people in white prefabricated cabins. It was dusk and groups of women squatted outside their front doors, preparing piles of foraged leaves to cook with oil and serve with rice or bread for dinner.

Jehan’s family rose stiffly from the floor when I arrived. Three sides of their single-room cabin were lined with faded mattresses and a neat pile of blankets occupied one corner. It was becoming chilly and we huddled close to a small kerosene stove. Jehan said that since her release, three days earlier, she had been unable to sleep. She could not stop worrying about her four siblings and her mother, who were still missing and believed to be in IS hands.

They were from Kocho, a village that IS did not attack until 15 August 2014, a day after the siege on Mount Sinjar was broken. When the jihadists stormed Kocho, the men were separated from the women and then shot. The UN estimates that up to 700 men and boys were murdered that day. Jehan was taken with other women, girls and infants by bus to the city of Mosul, 150 kilometres away, where she was later sold into “marriage” to an 18-year-old Libyan fighter with ambitions to become a suicide bomber. They lived together in Raqqa for six or seven months. He forced her to say Islamic prayers and made her promise to teach them to her family. In his will, he granted her freedom. According to IS’s religious leaders, if a fighter liberates his slave, he is guaranteed a
place in heaven.

When her “husband” blew himself up on a suicide mission in Syria in mid-2015, Jehan was free to move wherever she wished within IS territory. Perhaps she could even have planned an escape but she did not know then if she had any family to go home to. Instead, she stayed with an aunt who was kept as a slave in the city of Tal Afar. She moved several times and spent her final months in IS hands living in a guest house in Raqqa. It was populated by would-be jihadi brides who had joined the extremist group from all over the world: the UK, the US, France, New Zealand, Turkey and Pakistan. The women could browse paper files resembling CVs, which listed fighters’ interests and achievements alongside their photographs, to find a husband. She says that her role in the guest house was simply to study the Quran.

Towards the end of 2015, international air strikes on Raqqa intensified, causing terror in the guest house. In February, the five Yazidi women staying there persuaded IS militants to transfer them, together with their 14 children, to a small village. There they were less closely monitored by the jihadists and one hostage succeeded in calling her husband. In turn, the husband called Sherim, the rescue co-ordinator in Dohuk, who engineered an escape plan.

One day at noon, an Arab woman knocked on the door of the house – as they had been told by Sherim to expect – and drove the 19 hostages to the village of Tal Hamis. They spent a week hiding there, before a sheep farmer collected them and took them to his tent, where they stayed for one night. Another Arab smuggler walked them towards the town of Kobane, which has been under Syrian Kurdish control since January 2015, following a fierce four-month battle with IS. The smuggler instructed the women and children  to follow his footsteps exactly to avoid stepping on landmines.

In Kobane, a Kurdish smuggler met them and drove them to a Yazidi shrine in Sinjar, almost 500 kilometres away. There they met Sherim, who accompanied them for the final drive to Dohuk.  Jehan has since been questioned by Kurdish government agents and received medical check-ups but no other support, she says.

Hussein, the uncle who paid for her release, was one of the hundreds of men from Kocho rounded up for execution. He was shot three times, once in the back and twice in the leg and then lay, still as a corpse, among the dead bodies of his friends and neighbours until he could escape. He has been living in Rwanga for over a year and he is heavily in debt. Before he paid for Jehan’s release, he had already spent $20,000 buying back his wife. One of Jehan’s sisters recently managed to call him: she is being held as a slave in the Iraqi city of Fallujah but no one can afford the cost of her release. Another of Jehan’s uncles, named Salem, told me that he had spent $70,000 to buy back his relatives. The family raised the money by borrowing from displaced families in Rwanga and now some of their debtors are asking when they will be paid back. “We’re dead with our eyes open,” Salem said.

On a stormy morning, I travelled from Dohuk to Sinjar. Beyond the main checkpoint out of Kurdistan, there were few cars. We followed a potholed road that runs along the Syrian border. We passed Arab and Yazidi villages flattened in the fight against IS, grey houses whose concrete roofs had sometimes shattered into great, heavy plates and other times had curved and distorted to resemble folds of cloth. The driver listened to a new Yazidi radio station that played prayers, traditional love songs and poetry. “This time, it was a real ferman,” the voice on the radio said, speaking over the militaristic music. “The volcano of hunger came to our mountain . . .” The IS front line has now been pushed back to the south of Mount Sinjar. As they departed, IS left behind booby traps to kill or maim the first Yazidis to return to their abandoned homes or search for their relatives’ remains.

Some Yazidis feel that they can never go back  to their former houses, in villages of ghosts. Many have left for Europe, some illegally and others through special programmes: Germany has resettled around 1,000 Yazidis. Many people in IDP camps told me that they could never feel safe in Iraq again, each repeating the same story. They said that hours before IS invaded, the peshmerga stationed in the area, who were affiliated with the ruling Kurdistan Democratic Party, repeatedly promised that civilians would be protected and told them not to leave their homes. But the peshmerga unexpectedly retreated, taking their weapons with them. Before the Yazidis were attacked, they were betrayed. And long before that final betrayal, they were neglected and sidelined by Iraq’s Muslim majority.

There are other Yazidis who say they will never leave their homes, their shrines and the mountain that protected them during the darkest days of the ferman. The mayor of Snune, the largest town north of the mountain, told me that of the 23,000 families that lived in Sinjar Province in 2014, around 5,000 have come back. They have little to return to: few areas have running water, or electricity, or functioning schools and health clinics. Most are surviving on food handouts from NGOs, Iraq’s government or Kurdish fighters from Turkey.

Finally we reached Khanasur, the home village of the chef Abu Majed. Other than the checkpoint, guarded by two teenage female Yazidi fighters, the once bustling main street was empty. The shops, beauty salons and cafés were boarded up, the shutters spray-painted with the names of peshmerga battalions from Iraqi Kurdistan, Turkey and Syria. At the edge of the village, beyond an abandoned football pitch, we found Abu Majed’s restaurant. The rain had stopped and the cloud had lifted to reveal the long, rugged form of Mount Sinjar.

By peering over the high concrete wall, I could see the roof of the simple bungalow in which Abu Majed and his wife and five children once lived, as well as the tops of the trees in the restaurant garden, which were still strung with unlit fairy lights. A goatherd approached from the nearby scrubland, shaking her head. “Poor Abu Majed,” she said.

Sophie McBain is an NS contributing writer

Sophie McBain is a freelance writer based in Cairo. She was previously an assistant editor at the New Statesman.

This article first appeared in the 26 May 2016 issue of the New Statesman, The Brexit odd squad