Here′s why your brain is a time machine

Here's why your brain is a time machine and why we're different from other animals

Our lives seem controlled – even constrained – by time. But unlike other animals, humans can revisit the past and have visions of the future, as neuroscientist Dean Buonomano tells DW's Zulfikar Abbany.

Here's a sobering thought, lifted straight from Dean Buonomano's latest book, Your Brain is a Time Machine: How does the brain's architecture shape our ability to answer questions that it did not evolve to address? Among the many things the brain certainly did not evolve to understand was the brain itself. Another is the nature of time.

DW: So let's start with one of your own questions. Time: what the hell is it? Can you put it in a nutshell?

Dean Buonomano: Probably not! Or else philosophers over the past thousand years would have done so! Part of the fascination with time, the mystery of time, and the trouble we have defining it - you know, we all know what it is unless we're asked to explain what it is - is that it is more than one thing. I give this contrived example in the book, where I say, 'Einstein's talk on the nature of time started on time and seemed to last a long time.'

So we use the word time to mean many different things. We use time to mean clock time, and that's the easiest. Time is what clocks tell. But we're talking about the nature of time, the physical nature of time, what time is - is time a dimension, where the past and the future are equally real? Or is only the present real? That's the question of the nature of time, and it's a very deep question which I try to discuss.

Yes, you present this idea of two camps - in the one you have the "presentists," for whom only the present is real, and in the other you have the "eternalists."

And for the eternalist, the past, present and future are equally real. Eternalists treat time much like people treat space. For example, I know you're in Germany and you know I'm in Los Angeles, and they are different points in space. But we accept that those points in the east and the west are equally real. That's the case with time for eternalists. The past and the future are equally real. They just happen to be at an arbitrary point in what we call the present.

Grafik - Dean Buonomano zu Zeit - Two views of the nature of time

Two views of the nature of time: presentism versus eternalism

And where would you place yourself in that?

I think in physics there is a tendency to embrace eternalism, and that's in part due to Einstein's theory of relativity. But physics doesn't have any evidence that the universe is eternalist. There are reasons to believe it is based on interpretations of Einstein's theory of relativity. But I tend to favor presentism, in which there is something special about the present. The present is real, but the past and the future aren't real. But time is still relative, because my present is different from your present. 

How does that fit in with the idea of our brains being time machines?

Well, all animals have memories in the sense that they learn from the past. Pavlov's dog will salivate in response to the bell, because in the past, it remembers, or there is information there, that when that bell is presented food will be presented shortly after. But that doesn't mean the animal is reminiscing.

You and I, when we say remember we tend to mean some kind of conscious recollection. The terms are a bit fuzzy here, but when I say, 'Remember your last birthday or a wonderful trip you took,' you can actually revisit that in your head.

But even if other animals think about the past, the big difference is the future. The concept of saying, 'I have to get up early tomorrow because I have a phone meeting with Zulfikar in Germany,' that kind of thing, where I'm consciously preparing for the future, animals probably don't do that.

Dean Buonomano

Dean Buonomano: we may be losing touch with some of our internal clocks

Then there's the way we learn the concepts of time as children. You describe a lovely experiment involving kids and slugs …

Yes, and I think this is a good transition, because part of the reason why other animals are unable to conceptualize the past, present and future, or have a concept of the passage of time, is because it's really complicated, and kids show this.

There are these very old experiments that have been confirmed where, if you show five year olds two little trains, or slugs, starting at the same time, and one of them travels farther than the other, but they both end at the same time, children will think that the one that traveled farther, and which was just going at a faster speed, was traveling for more time, because they don't have this clear distinction, or concept, of the amount of time. But if you think about it, you feel sorry for children because it's so confusing.

Grafik - Dean Buonomano zu Zeit: Ego-moving and time moving perspective

If your meeting on Wednesday gets "moved forward" by two days, what day do you think it's on now? Monday or Friday?

I wonder whether our using clocks in the external world is just a way of getting a handle on time, because clock time is arbitrary. We round the number of hours in a day to 24, but it's not strictly 24 hours, is it? So is this another case of humans trying to control nature in a way that perhaps we can't?

That's a good perspective in the sense that you said we use clocks to get a handle on the passage of time. It's not natural for children to pick up the idea of a clock. It's a thing we learn culturally.

And our ancestors a hundred thousand years ago, even if they had a clock, they probably had no use for it most of the time. All animals look at the sunrise and sunset, so in a sense that's a clock. But, yes, I think for humans, the concept of clocks emerged fairly late in our evolution.

So do you think we might eventually lose a sense of time as our lives get more digital or even space bound? I'm thinking about the idea that we can no longer store telephone numbers in our heads, but also with space travel, some of our concepts of space time are completely different to what we have on Earth.

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No, I don't think so. You use it [time] in different ways. And we can learn to do timing better if what you do in your life, or in your interests, relies on it. But, on another hand, what you're saying is true in the sense that we rely on external time. I don't go to sleep when I'm tired - I go to sleep when the clock says it's midnight. We're overriding our internal clocks, but they might be more important than external ones. So in a sense I think we're losing touch with some of our internal clocks. There is some truth to that.

Dean Buonomano is a professor of neurobiology and psychology at UCLA and a leading theorist on the neuroscience of time. His latest book, Your Brain is a Time Machine: The Neuroscience and Physics of Time, is published by W.W. Norton (2017).


The NFL's first CTE diagnosis

"Iron Mike" Webster won four Super Bowls as a center for the Pittsburgh Steelers in the 1970s. However, after his career ended, the many hits to the head that he had received as a football player took their toll on his health. He died in 2002 at the age of just 50. After his death, Webster was diagnosed as having had chronic traumatic encephalopathy (CTE), a neurodegenerative disease.


A Hollywood film

Bennet Omalu, a forensic neuropathologist (pictured above, second from left) was the first to diagnose CTE in Webster and other former NFL players. He continued his research despite widespread and strong resistance to his findings. In 2015 director Peter Landesmann (above, right) directed the film "Concussion," in which actor Will Smith (left) played Omalu.


Gradual changes to the brain

Symptoms such as loss of speech, depression and dementia, which can be an indication of CTE, were first observed in boxers decades ago. Repeated blows to the head release the tau protein which accumulates in the brain. Those affected can experience changes to their personality, problems with aggression and even become susceptible to thoughts of suicide.


Suicide and a final wish

Between 2008 and 2015 Terry Long, Tom McHale, Jovan Belcher, Adrian Robinson and Junior Seau were among the former NFL players who committed suicide. In 2011, Dave Duerson, a former safety, shot himself through the heart instead of in the head. In his suicide note he asked that his brain be examined to see if he had CTE. Doctors found clear signs that he had had the disease.


The biggest stage

Head injuries occur in soccer as well. In the final of the 2014 World Cup in Rio de Janeiro, German midfielder Christoph Kramer was knocked out. He soldiered on for 14 minutes after the injury, which was a big risk, because a second hit shortly afterwards increases the danger of long-term damage. Even now, there is no universally agreed procedure for diagnosing brain injuries on the sidelines.


Risk varies by position

Brain injuries in soccer tend to occur when two players clash heads when going for ball or as the result of an elbow to the head. A recent study by the Federal Institute of Sports Sciences has found that the risk of head injury in soccer varies according to a player's position. Defenders are most at risk, followed by midfielders and strikers. The risk is by far the lowest for goalkeepers.


Which is the worst sport for concussions?

A study conducted by the Federal Institute for Sports Sciences, showed that rugby players are at the highest risk among athletes of suffering concussion. They are followed by American football players, ice hockey players and basketball players. Brain injuries are not as common in soccer, but in Germany, where it is the biggest sport, in absolute terms, it is where the most concussions occur.

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