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Professor Thomas Suddendorf
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‘The human mind is a virtual time machine’

Our ability to think about the future makes humans unique. Professor Thomas Suddendorf tells Deputy Editor Shaoni Bhattacharya how this capability has shaped human psychology and evolution.

31 January 2023

The book you've written with Jonathan Redshaw and Adam Bulley has an intriguing title: what do you mean by 'The Invention of Tomorrow'?

'The Invention of Tomorrow' refers to the evolution of our ability to think about the future. Our book is an attempt to get to grips with the nature and origins of this ability and its role in the human story.

Why is the ability for 'mental time travel' or 'foresight' important in human evolution?

The human mind is a virtual time machine. With it you can relive past events and imagine future situations, even if you have never experienced similar situations before. Because humans are mental time travellers, we can prepare for opportunities and threats well in advance, trying to shape the future to our own design. Early humans increasingly predicted the goings-on in their environments – predators and prey, seasons and storms – until eventually they plotted their way to some level of dominance wherever they went. Arguably foresight, the ability to anticipate events and act accordingly, is the most powerful tool at our disposal, even if we often get it terribly wrong.

You highlight that psychology has traditionally focused much more on memory than foresight – why do you think that is?

Perhaps one reason is that memory is easier to study. Experimental psychologists since the 19th century have been presenting participants with materials to then measure how well they are retained later. But ultimately the future is much more important than the past, as that is all anyone can do anything about. 

The book mentions some interesting human case studies – could you tell us briefly about one that illustrates what happens when the brain loses some of this capacity?

In one of the worst cases of amnesia known to science, the English musician Clive Wearing suffered brain damage from a herpes infection that has left him unable to recall a single event from his past. Despite still being lucid and intelligent, Clive cannot form new memories and can track the flow of events only in the order of seconds. He lost not only his ability to recall ever having given a performance, but also his ability to travel mentally into the future and imagine giving a performance next week – or at any future time for that matter. Clive is in no position to plan for the weekend or look forward to a holiday. We do appear to need the same mental time machine to go both backwards and forwards.

Where in the brain does the capability for mental time travel lie, and is there a seminal experiment which shows this?

When participants in a brain scanner are asked to remember the past and imagine the future, it turns out that many of the same brain regions become active. One of these regions, the hippocampus, was severely affected in Clive Wearing's brain. There have been many experiments demonstrating commonalities between mental time travel into the past and into the future. In one of our studies we asked young children questions about their past and future and found a link between their ability to accurately recall what they did yesterday and to report what they would do tomorrow. Similarly, as people age the richness and accuracy of memory and foresight appear to decline in parallel. 

Your book focuses on evolution, but how does our capacity for foresight relate to some mental health conditions, for example anxiety?

Problems with our virtual time machine are central to many psychological challenges and this has become a hot topic in psychopathology. Depression can involve hopelessness about the future. Anxiety involves excessive thinking about possible bad outcomes. Even worry about worrying too much. But foresight is also an avenue for intervention. We seek help because we yearn for a better future, and can plan to resolve the problems we face.  

Which other animals have the ability for foresight?

Foresight is not one ability but the product of a range of capacities working in concert. Other animals have some of these capacities and can act in future-directed ways. In our book we describe curious examples of competences in crows, dolphins, chimpanzees and other animals. For example, chimpanzees may carry a rock a hundred yards to crack open nuts at another location, and in experiments we have found that crows can pick a tool for a problem they will face only a few minutes later. 

Are humans unique in their capacity for imagining the future as Seneca and Schopenhauer suggested, as your book mentions? How do we differ from other species?

There appears to be something profoundly distinct about the human capacity to think about the future. Even those nonhuman animals that demonstrate some competencies tend to fall short when it comes to more remote future events, and when it comes to taking multiple possibilities into account. For example, chimpanzees and crows have not been observed making even simple contingency plans. 

At what point did humans or our hominin forebears evolve foresight – was it in response to anything?

The invention of tomorrow did not happen overnight, as it were. Our ancestors gradually acquired their remarkable mental time machines over millions of years, leaving clues in the archaeological record of their advancing capacities. In the book, we take the reader on a journey through some of the key milestones, such as when our ancestors began to assemble stone-tipped spears that would only later kill from a distance or when they started to craft carrying devices that enabled them to ferry provisions to points in space and time, wherever and whenever they might be needed. Although the precise forces bringing these changes about remain unknown, we discuss several plausible drivers for these advances.

What about the downsides of foresight? In your book you link this to the human propensity for war, causing extinctions and damaging the environment – could you say a little about this?

Foresight comes with many downsides. It confronts us with the most unwelcome facts, such as our own mortality. It gave us more reasons to fight and made fighting more dependent on reason – with all the horribleness this entails.

And being able to think about the future does of course not mean we are clairvoyants. We persistently predict things that do not happen and frequently fail to foresee those that do. And these failures can have treacherous consequences. For instance, to smooth the operation of car engines, the inventor Thomas Midgley Jr. introduced lead to gasoline, which he did not anticipate would turn out to produce one of the worst pollutants ever devised. Nor did he foresee that the CFC (chlorofluorocarbon) he introduced to refrigerators would be a major cause of ozone depletion. 

By and large, we can no longer claim ignorance about the environmental consequences of our actions. Continuing to litter, to emit and to destroy is reckless, and often simply driven by a focus on immediate monetary gains and wilful neglect of factors outside of market forces. In spite of our foresight, we often tend to discount the future, to prioritise short-term benefits at the expense of long-term costs. As the only animal on the planet capable of foreseeing the distant consequences of their actions, we have choices faced by no other creature. Our farsightedness burdens us, and us alone, with responsibility for the future.

How can we humans use our mental time-travelling abilities for good?

Foresight confronts us with many conundrums, and we incessantly debate what should be done to create a better future. On an individual level, we can make better decisions when we are aware of the many shortcomings and biases that affect our thoughts about the future. Throughout the book, we find that – somewhat paradoxically – some of the most remarkable powers of foresight can be derived from awareness of its limits.

On a global scale, we can now foresee many devastating possibilities in terms of pollution, climate change, or mass extinctions. To plot our way out of our troubles we will need to harness our tremendous capacities to predict, plan, and prepare, to strategise, simulate, and scientifically assess. With the right balance of confidence and humility we hope humanity can steer the ship into a brighter tomorrow. Future generations may hold us morally responsible for our choices.

Thomas Suddendorf is a professor of Psychology at the University of Queensland, Australia. The Invention of Tomorrow: A Natural History of Foresight by Thomas Suddendorf, Jonathan Redshaw & Adam Bulley is published by Basic Books (£25), and is available now.