Time Warped

by Claudia Hammond

  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.83 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.

  The second area is the parietal lobe. These are found one on each side towards the back of the head, at the top. It is here that sensory signals from the rest of the body are processed and it is also where letters are combined into words and words into thoughts. Intriguingly, part of this area also allows us to find our way around the world. This navigational function sheds more light on the shared mechanisms for thinking about time and space that I was discussing in Chapter Three. It suggests that we might conjure up the past by imagining pictures in the mind’s eye, just as we do when we’re trying to find our way to a place we have visited previously. The patients with amnesia found it particularly difficult to imagine the spaces in which new events might take place.85 When asked to imagine a future scenario where they were standing in the main hall of a museum, people without brain injuries tend to describe features such as a marble floor, a domed ceiling or paintings on the wall, but the people with amnesia were unable to add these elements to their vision of the room. They didn’t find the task any harder and even considered their imaginary room to be quite realistic, but were less likely to mention objects, feelings, senses or anything to do with the location of themselves in the room. Somehow the spatial context was missing, backing up the idea that we use space in order to construct a sense of time in our minds.

  The third area activated by thinking about either the past or the future is the medial temporal lobe. This contains the all-important hippocampus, and regulates memory, learning, language and emotions. Although the same parts of the brain are used, imagining the future takes more brain power than remembering the past. I love the fact that the further into the future we transport ourselves, the more active the hippocampus becomes. It is intriguing too that some of the brain regions used to imagine the future are also employed when we consider what someone else might be thinking, when we try to simulate their state of mind. This suggests that during future thinking we are doing something similar – simulating our own state of mind in another time and place. There is still much to be learnt about the workings of this process, but it does appear to be something that’s uniquely human.

  CAN YOUR DOG PICTURE NEXT WEEK?

  If you have ever owned a dog it is tempting to believe that in idle moments your dog thinks back fondly on the best walks you have ever had together, reminiscing about the time they found a dead rabbit, the afternoon where they were allowed to run wild in fields chasing other dogs, the occasion where they managed to strain enough at the lead to reach some chocolate buttons caught under a shop counter. Unfortunately it is unlikely that dogs recall these happy times at all. They can remember how to navigate their way to a favourite patch of grass, and will tug at the lead to get there, but as far as we know they have no way of remembering the individual events that occurred there. This would suggest that they can’t time-travel into the future either. They can’t decide to picture themselves on Christmas Day lying by the fire gnawing a bone. So if dogs can’t do it, what about other animals that are known for their intelligence?

  Panzee is a female chimpanzee who is clever enough to distinguish a pint from a half pint. Using a keyboard she can identify certain foods and objects and after years of training from Charles Menzel, an anthropologist at Georgia State University in Atlanta, she has learned to use 256 different symbols. Yet she displays no evidence of future thinking. She can point to the place where she has hidden some food previously, but this demonstrates that she has memorised the location, not that she can remember the action of hiding the food or picture retrieving it. There are of course animals that appear to plan ahead. How about the impressive accuracy with which squirrels return to the precise spot to dig up the nuts they buried there several months earlier? You could interpret this as evidence both of a reliable memory and an understanding of their future needs during the changing seasons. However, some naturalists now believe that squirrels simply start digging in typical hiding places and have no idea whether they are finding their own cache or one buried by another squirrel. You could argue that by hiding food at all they are planning for the future, but an instinct to hoard food is not the same as imagining themselves feeling hungry in the future and making plans accordingly.

  Of the animals that have been studied, it is a bird called the western scrub jay which comes closest to having the human concept of a past and a future. These birds not only look smart with their shiny, blue plumage, they are smart. Native to North America, they belong to the same family as rooks, crows and ravens and are among the most intelligent of all birds, but it is their tendency to hoard that interests comparative psychologists like Nicola Clayton at Cambridge University. If they experience a food shortage they learn to gather food and hide it for later. In experiments conducted at Cambridge University, Nicola Clayton has found scrub jays will even plan for the future when they have everything they need in the present.

  Nuts stay fresher for longer underground than dead worms. Scrub jays know this and will select caches accordingly, demonstrating that they not only remember where they hid the food, but what it was and how much time has elapsed since they created the cache. They even remember which other birds were watching them when they hid the food and will re-cache if they know they were observed by other birds and have previously stolen food themselves (not all of them do). This suggests they
are utilising their experience rather than relying on instinct alone to plan for the future and it provides compelling evidence for their planning skills and reliance on memory. The latest research from Costa Rica has revealed that 21 other species of bird, from the orange-billed nightingale thrush to the white-whiskered puffbird, might have similar skills. It has just been discovered that in a practice known as bivouac-checking, these birds learn to check ant nests (or bivouacs) at the end of a day in order to follow the army of ants the following day when they go out on raids, sweeping through the forest to drive out insects.86 This appears to be evidence of memory and planning.

  But again the question has to be asked as to whether this demonstrates future thinking in the human sense. In order to hoard or re-cache food the birds do not necessarily have to imagine themselves in a future where there is none. Once again it is important to distinguish between knowledge of the past and future and actually re-experiencing the past or pre-experiencing the future. If I ask you to imagine where the scissors are located in your house, there is a difference between you picturing them lying in a drawer and remembering the action of putting them back there the last time you used them.

  Another very intelligent animal, the dolphin, shows signs of the ability to time-travel mentally into the recent past. Dolphins can be trained to ‘do something they’ve not recently done’, so at a given signal they will perform a trick they have not done for some time. This suggests that they do have some recent autobiographical memory, but again the evidence of true mental time-travel in animals just isn’t there. Some people find this disappointing; we seem to like the idea that animals have memories and imaginations like ours, especially when it comes to our pets. A psychologist who has done a great deal of work in this field, Thomas Suddendorf, even apologises for being such a killjoy.87 And it’s not just animals who are so deprived. Babies are forced to live in the here and now too, unable to escape mentally into the future. It is not until the age of three or four that they begin to be able to imagine a future where they might feel differently, where they can anticipate or fear events. This imagining helps them to begin to develop the crucial skill of emotional regulation, where they find ways to control their emotions. Adults can comfort themselves with the knowledge that the agonising pain from a badly stubbed toe will not last forever, because they know this from experience and can easily imagine a future where their toe doesn’t hurt at all. Babies are stuck in the present, unaware that they might feel differently in the future.

  WHAT ARE YOU DOING TOMORROW?

  Before I begin an interview for a radio programme, I need to ask the person a question to get them talking enough to check the sound levels. The classic question is, ‘What did you have for breakfast?’ but too many people give one-word answers like ‘nothing’ or ‘toast’, responses too short to be of any technical use. So I like to ask people what they are planning to do that afternoon or the following day. Last week a woman told me she was going straight back home because two tree surgeons had arrived at her house with chainsaws to sort out a tree in her garden, but appeared to be drunk. She was keen to get back to discover what would be left of her garden, or even of the men themselves. The answers I get are rarely this dramatic. It is an easy question, or it is if you are an adult. If you are three years old it is much more difficult. In one experiment only a third of three-year-olds could give a plausible answer as to what they might do the next day, but within a year or two their sense of the future has developed to the extent that two-thirds of them can do it.88

  With any tests on young children there is always the issue of whether it is really their thinking that is holding them back or their verbal ability. Can we be sure that they understand the wording of the question? Most three-year-olds know that tomorrow is in the future, although they don’t always realise that it denotes the next day. What they do know is whether or not they like pretzels. So to overcome any verbal difficulties the psychologist Cristina Atance gave a group of children some pretzels to eat. Once the salt had made them thirsty she gave them a choice of more pretzels or a glass of water. Most kids chose water. But when she asked them what they would like to have the next day, while most adults opt for more pretzels, most small children still chose the water, unable to pitch themselves mentally forward into a future where they would no longer be thirsty and would be keen for more pretzels.89 If you think back to the areas of the brain involved in imagining the future, it is not surprising that toddlers find it difficult. Two out of three of these areas, the parietal and frontal lobes, do not develop sufficiently until the second or third year of life. This suggests that small children have an extreme form of the empathy gap that we can all experience on occasion, which leaves us unable to imagine that we might feel differently in the future. If you’re packing to go on holiday to a hot country, but at home it’s snowing, it is tempting to pack plenty of socks and a jumper because it’s so hard to imagine ever feeling too hot.

  MEMORIES FOR EVENTS THAT NEVER HAPPENED

  Ten years ago I took part in an experiment on pain tolerance that involved submerging my arm into a bucket of iced water and holding it there for as long I could. At first it seemed fine and I thought I could handle the discomfort. It was only cold water after all. Then a deep ache gradually spread up my arm and the pain got worse and worse. I can still remember the feeling of all-encompassing agony that was impossible to ignore. I could stand just 90 seconds before I pulled my freezing, numb arm out of the water. There is just one problem with this memory; it didn’t actually happen. Until recently I was convinced that it did. I had recorded myself taking the pain test, along with a male and female volunteer, for a radio programme on sex differences in pain tolerance. When I was making a new programme on pain relief this seemed like the perfect piece of archive to include. I found the tape and handed it to the producer, describing to her the torture of holding my arm in that bucket and how I’d discovered that I had a low pain threshold. The patient producer listened to an hour of audio, searching for the part where I put my arm into the icy water, but it turns out that I didn’t do it. I had bravely recorded two other people taking the test, without doing it myself. I am convinced I can remember exactly what that pain was like, but I recorded the whole session and so the evidence is there, or rather isn’t there, on the tape. It didn’t happen.

  This fallibility of memory is uncomfortable, but it could be the consequence of our ability to imagine the future. The fact that memories are so crucial to future thinking could explain one of the long-standing mysteries of memory – why it so often lets us down. Elizabeth Loftus has become one of the most eminent living psychologists for her demonstration that memory is not like a videotape. These are some of my all-time favourite experiments. They’re relatively simple, yet so cleverly constructed that they have had a huge impact on the way the law courts consider evidence from eye witnesses in criminal trials. Loftus succeeded in implanting false memories in people’s minds, not through hypnosis, but simply by convincing them that they remembered events that had never taken place. Using interviews with relatives to give her some background information about true events, she would then discuss the past with an individual and make them believe they had been lost in a shopping centre as a child or remembered kissing a giant green frog or that they met Bugs Bunny at Disneyland. This might sound plausible until you recall that Bugs Bunny is a Warner Brothers character, so he’s never going to be allowed into Disneyland. Our memories are flexible. They don’t enter our minds perfectly formed and then remain intact in the mind’s archive, waiting for us to call them up. Decades of evidence demonstrates that we change memories as we lay them down, we alter them again if new information comes to light, and then, if it helps us to make sense of events, we change them again when we recall them. Memory is reconstructive. None of this is done dishonestly or even consciously. But while the flexible nature of our memories presents a problem for the reliability of eyewitness testimony, this same flexibility could be the key to us imagining the fut
ure at all.

  If memories were fixed like videotapes, then picturing a new situation would be time-consuming. Let’s pretend that you want to picture yourself arriving by double-decker bus at a tropical beach for the wedding of Johnny Depp to your best friend. In an instant you can do this. If memories were rigid this would be a complex process. You would need to do the equivalent of finding your personally taped memories of sitting on buses and visiting your best friend, and then you’d need to order up clips from the mind’s archive of films starring Johnny Depp and TV programmes featuring tropical beach weddings. These memories could be years, even decades apart. Once you have extracted all the necessary elements you’d then need to splice them together to invent this scene. Cognitively it sounds like hard work and would be if we had to do it this way. In fact the flexibility of our memories makes it relatively easy because we can meld all these different memories together seamlessly to invent a new imaginary scene, one which we have never even contemplated before, let alone witnessed. The flexibility of memory seems to be the key to imagining a future.90 Our millions of fragments of memories from different times of our lives are not set in stone; they can change, giving us endless, instant imaginative possibilities. Our unreliable memories might feel like a deficit, but they facilitate mental time-travel into the future.

  It is obvious that we learn from experience, but taking this one step further perhaps the primary purpose of memory has nothing to do with looking back, but more to do with allowing us to look forward and imagine possible futures. This is not a new idea. Medieval illustrations of the mind from the fourteenth century depict memories like snakes feeding into the imagination and, long before this, both Aristotle and Galen described memories not as archives of our lives, but as tools for the imagination. It was in 1985 that the Swedish neuroscientist David Ingvar proposed the modern version of this idea. Since then there has been a flurry of studies on future thinking, although, as I’ve mentioned, this research is still dwarfed by the attention given to memory.