Time Warped (23 page)

Why were they so insistent? In order to stop the scientific calamity of the most famous brain in neuroscience being incinerated.

This outcome averted, ice blankets were packed around the elderly man’s head and his body was driven in a hearse to Boston a hundred miles away. Meanwhile Jacopo Annese, a neuroanatomist was on a plane from California. He had been selected by Suzanne as the perfect person for the job – someone advanced enough in their career to be highly skilled, yet prepared to devote the necessary time to the project. By midnight scans of the brain while it remained inside the skull had been completed. Next morning Suzanne watched through the viewing window of the pathology department while Jacopo and two colleagues carefully extracted the brain from the body. The following day Jacopo flew back to San Diego and ‘Henry’, as he couldn’t help saying, occupied the seat next to him.

It might seem rather tasteless to give a brain, hanging upside down in formaldehyde in a plastic vat inside a cooler, a name. But for the scientists it was somehow appropriate. Professor Corkin had taken responsibility for Henry Molaison, a vulnerable soul in life, and ensured he was well looked after at the Bickford Nursing Home. She had protected his identity – for decades in text books he was known only as ‘H.M.’ – and grown very fond of him. But in scientific terms, it was his brain that made Henry so special. For more than 45 years, Suzanne had thought more about the workings of this brain than any other – what it could remember, what it could learn, what it could predict. Now finally she and Jacopo were to have the opportunity to see inside it.

Why were they so excited? Because Henry had lived two-thirds of his life locked in an eternal present.

When he was 27 years old, Henry underwent brain surgery to try to prevent the multiple epileptic seizures he
experienced daily – seizures that would probably have killed him within a few years if no action had been taken. The surgeon, Dr William Scoville, took a silver straw, inserted it into Henry’s brain and slowly sucked out part of the hippocampus, the tiny seahorse-shaped area deep inside. The operation appeared to be a success. Henry recovered well and the seizures ceased. But Scoville gradually realised that something had gone very wrong. Henry could not remember anything new that happened to him. Although he could recall incidents from his childhood, people he had met the previous day were like strangers to him. Every face was new. Every experience was new. He had no idea what he had been doing even an hour before. The surgery had caused anterograde amnesia. Henry had his old memories, but he could never again make any new ones.

Although Henry’s case features in many neuroscience and psychology textbooks, it usually appears in the chapter on memory. There is, though, another aspect to amnesia, one that’s less well-known: the loss of the ability to imagine the future. Henry exhibited just these twin symptoms: no sense of a past after the accident, but no sense of a future either.

As I’ve illustrated throughout this book, we construct our own sense of time in our minds, but nowhere is this clearer than with our mental images of the future. At will, we can choose to imagine tomorrow, next week or 1,000 years hence. This ability has nothing to do clairvoyance. The chances are that the future we imagine will not turn out exactly that way. Indeed, such is the power of our imagination that we can clearly picture a future that not only won’t happen, but could
never
happen. This strange ability to pitch ourselves
forward in time – called future thinking – is the opposite of memory. But as I’ll show in this chapter, it is connected to it. For the mind uses both our sense of space and our memories to create a sense of the future.

On average people think about the future 59 times a day or once every 16 minutes during waking hours.
⁷⁷
Indeed research in this field reveals a staggering finding: contemplating the future could be the brain’s
default
mode of operation. But this is not wasteful daydreaming or, as the phrase goes, a case of ‘wishing our lives away’.

Mental time-travel into the future matters – and is useful. It affects our judgements, our emotional states and the decisions we make, sometimes for the worse. And my explorations of future thinking will also reveal something rather surprising about the reasons for the fallibility of our memories of the past.

TIME
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TRAVELLING INTO THE FUTURE

There has been more than a century of research into the way our memories work, but future thinking is a far newer area of study. The most significant finding is the degree to which future thinking relies on mental time-travel in the opposite direction – into the past. This can even explain one of the mysteries of memory – why it so often lets us down, why researchers like Marigold Linton found studying her own memory to be so painful. We need our memory to be a reconstructive process, and one that’s flexible and even unreliable, to allow us to imagine the future. The evidence for this idea comes from a range of sources, beginning with
patients like Henry. Hundreds of cases of amnesia have been reported in the medical literature and their doctors have often noted that these patients found it difficult not only to remember the past, but to imagine the future. They are unable to picture what they might do the following day, let alone in a decade’s time. Although many doctors have made this observation, future thinking has only been studied systematically in a handful of these patients, compared with the copious amount of research done on memory skills.

There once was a man known in the medical literature as ‘N.N.’, which stood for ‘No Name’. He was driving up the exit slip-road from a motorway in 1981 when he came off his motorbike and sustained a serious head injury. Like Henry, N.N. doesn’t remember new information and still reacts with horror every time he hears what happened on 9/11.
⁷⁸
He later became known by his real initials K.C. and was visited by the influential memory theorist Endel Tulving. Tulving was famous for differentiating between semantic memory – our memory for knowledge, so for example that Canberra is the capital of Australia; and episodic memory – the memory for the personal events that happen to us, for example visiting Canberra. Tulving asked K.C. some simple questions: ‘What are you going to do tomorrow?’ and ‘What are your plans for the summer?’ K.C. was unable to answer either. When Tulving asked him what was in his mind, he replied that it was blank. Hard as he tried, he could not hold ideas of the future in mind, and 30 years later he still can’t. Some patients, such as one known as D.B., can imagine political events in the future, but find
personal
future events particularly difficult to envisage.
⁷⁹
It’s striking that not only do these patients
struggle to imagine a future when asked to do so, but they appear to have no desire to imagine one either.

Just as semantic memory and episodic memory are different, a similar distinction applies to the way we think of the future. There is a difference between sitting in midwinter
knowing
the fact that it will be warmer when summer comes and
imagining
yourself sitting in the sunshine next summer feeling the heat on your skin. This latter mental time-travel into the future through imagination has been defined as episodic future thinking, which for simplicity I refer to here as future thinking. It is part of a more general system of mental time-travel that Endel Tulving said makes up our autonoetic consciousness. This is the sense we have of ourselves as persisting across time, and it is manifest in our ability to re-experience or pre-experience events. This pre-experiencing involves imagining what an activity might feel like, not merely intending to do it. So you might notice in your diary that you’re meeting some friends for a pub lunch. It is your prospective memory that reminds you to turn up at the right time, but it is future thinking that means you can picture yourself ordering a drink, finding a table and reading the blackboard to see what specials they have. With future thinking you project yourself forwards mentally to imagine the actual experience. This is different from actively planning, and it is this skill that seems to set us apart from other animals.

Mental time-travel need not involve vast stretches of time. Often it will concern what you have just done or are about to do. If you take the example of a job interview, there’s the mental rehearsal of the questions beforehand, followed afterwards by the agonising, repeated replaying of the worst
moments, coupled with the imagination of a possible past, of the things you wished you’d said. These were possible futures. Now they are part of an impossible past.

Demis Hassabis and Eleanor Maguire were the first neuroscientists to carry out a structured investigation of future thinking in people with brain injuries. They found that even when they gave them suggestions for all the sensory details that might be present in a future scenario – the sights, the smells and the sounds – they were still unable to imagine the scene.
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These five patients had a range of scores on tests of IQ and memory skills, but when it came to imagining the future four of them did very poorly, despite the fact that the scenarios used were everyday enough not to appear to necessitate access to detailed memories.

It is not only people with brain injuries who find future thinking difficult. Anyone with a poor autobiographical memory will also find it harder to project themselves into the future. This includes very young children, people with schizophrenia, Alzheimer’s disease or depression and those who are feeling suicidal.
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The more delusions and hallucinations a person with psychosis experiences, the harder it is for them to hold an idea of the future in mind, depriving them of the agency that mental time-travel can bring.
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As the decades pass we discuss our failing memories, but this is accompanied by something we tend to notice less – a decline in our ability to imagine the future. This lends weight once again to the idea that we rely on past memories in order to conjure up ideas of time yet to come.

The part of Henry’s brain that was most damaged was the hippocampus. It gets its name from its shape – it curls
around in a narrow arc similar to a seahorse. Not long ago I stood on an old converted squash court that now houses a brain bank. There were shelves and shelves of brains in vats. The neuroscientist carefully handed me one of their six thousand brains and pointed out the hippocampus. It was extraordinary to think that an area that is only four centimetres long and formed so delicately could hold the key to the lifetime of memories that form a person’s identity. We know this area to be crucial to memory, but the experiences of the patients with amnesia would suggest that it also plays a part in imagining the future. The evidence from these people begins to build up a picture of the way the brain holds ideas of the future in mind, one which is backed up by scans of living brains.

To understand this better, think of something you know you are going to do next week, but not something that happens every week. Now try to come up with a detailed picture of this event. If it’s indoors, what will the room look like? If there are people, what will they be wearing? Look closely at the details you have conjured up, apparently from nowhere, and you will probably find they involve memories from your past. I know that I’m going to Oxford next week to interview a psychology professor about his work on group cohesion. I’ve never met him in person, nor been to his office, yet I can summon up a rough picture of a scene where we sit on faded velvet armchairs in his wood-panelled office. The desk is covered in piles of paper and as well as floor-to-ceiling bookshelves along one wall, there are stacks of books on the carpet too. In fact this picture seems to be a combination of what I saw the last time I went to meet
an Oxford professor and scenes from films like
Educating Rita
. I could be wrong of course and his office might be modern and minimalist. Nevertheless it is clear that my vision of the future is an amalgamation of any relevant memories I can find. By recombining old memories we are able to project ourselves forward into the future, giving us endless combinations from which to select the most plausible possibilities. Like a remix, utilising these memories allows us to preview future events in a window in the mind.

Considering this, it is not surprising that if you scan a person’s brain while asking them to imagine a future event, one of the areas that shows activity is the hippocampus, the repository of memories, the very same area that was sucked out of Henry’s brain with a straw. In fact the regions of the brain used to recall the past largely overlap with those used to imagine the future.
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Memory is essentially a reconstructive process; when we want to re-experience an event we don’t summon up a tape from the library. We reconstruct it and even alter that memory if new information has changed our views since it first happened. A similar process takes place when we imagine the future.

The neural signatures of remembering the past and imagining the future are remarkably alike. Researchers have investigated this by giving people a key word or phrase and asking them to imagine different past and future scenarios involving that word. One researcher, Karl Szpunar, gave people the name Bill Clinton.
⁸⁴
People reported finding the task easy (maybe it’s just me, but one particular Oval Office scene does come to mind, so I hope this didn’t skew their study). Three main regions of the brain were involved both
in thinking about the past and the future. The first is the frontal lobe. This is the area behind our foreheads that houses working memory and is responsible for making decisions and solving problems. The frontal lobes also ensure that memories from the past are not mistaken for real life.