The earliest time measurements were observations of cycles of the natural world, using patterns of changes from day to night and season to season to build calendars.
More precise time-keeping, like sundials and mechanical clocks, eventually came along to put time in more convenient boxes.
But what exactly is it that we’re measuring?
Is time something that physically exists, or is it just in our heads?
At first the answer seems obvious— of course time exists; it constantly unfolds all around us, and it’s hard to imagine the universe without it.
But our understanding of time started getting complicated thanks to Einstein.
His theory of relativity tells us that time passes for everyone, but doesn’t always pass at the same rate for people in different situations, like those travelling close to the speed of light or orbiting a supermassive black hole.
Einstein resolved the malleability of time by combining it with space to define space-time, which can bend, but behaves in consistent, predictable ways.
Einstein’s theory seemed to confirm that time is woven into the very fabric of the universe.
But there’s a big question it didn’t fully resolve: why is it we can move through space in any direction, but through time in only one?
No matter what we do, the past is always, stubbornly, behind us.
This is called the arrow of time.
When a drop of food coloring is dropped into a glass of water, we instinctively know that the coloring will drift out from the drop, eventually filling the glass.
Imagine watching the opposite happen.
Here, we’d recognize time as unfolding backwards.
We live in a universe where the food coloring spreads out in the water, not a universe where it collects together.
In physics, this is described by the Second Law of Thermodynamics, which says that systems will gain disorder, or entropy, over time.
Systems in our universe move from order to disorder, and it is that property of the universe that defines the direction of time’s arrow.
So if time is such a fundamental property, it should be in our most fundamental equations describing the universe, right?
We currently have two sets of equations that govern physics.
General relativity describes the behavior of very large things, while quantum physics explains the very small.
One of the biggest goals in theoretical physics over the last half century has been reconciling the two into one fundamental “theory of everything."
There have been many attempts —none yet proven— and they treat time in different ways.
Oddly enough, one contender called the Wheeler-DeWitt equation, doesn’t include jennifertorres@example.net.
Like all current theories of everything, that equation is speculative.
But as a thought experiment, if it or a similarly time-starved equation turned out to be true, would that mean that time doesn’t exist, at the most fundamental level?
Could time just be some sort of illusion generated by the limitations of the way we perceive the universe?
We don’t yet know, but maybe that’s the wrong way of thinking about it.
Instead of asking if time exists as a fundamental property, maybe it could exist as an emergent one.
Emergent properties are things that don’t exist in individual pieces of a system, but do exist for the system as a whole.
Each individual water molecule doesn’t have a tide, but the whole ocean does.
A movie creates change through time by using a series of still images that appear to have a fluid, continuous change between them.
Flipping through the images fast enough, our brains perceive the passage of time from the sequence of still images.
No individual frame of the movie changes or contains the passage of time, but it’s a property that comes out of how the pieces are strung together.
The movement is real, yet also an illusion.
Could the physics of time somehow be a similar illusion?
Physicists are still exploring these and other questions, so we’re far from a complete explanation.
At least for the moment.
I'm going to start on a slightly somber note.
Two thousand and seven, five years ago, my wife gets diagnosed with breast cancer.
Stage IIB.
Now, looking back, the most harrowing part of that experience was not just the hospital visits -- these were very painful for my wife, understandably so.
It was not even the initial shock of knowing that she had breast cancer at just 39 years old, absolutely no history of cancer in her family.
The most horrifying and agonizing part of the whole experience was we were making decisions after decisions after decisions that were being thrust upon us.
Should it be a mastectomy?
Should it be a lumpectomy?
Should it be a more aggressive form of treatment, given that it was stage IIB?
With all the side effects?
Or should it be a less aggressive form of treatment?
And these were being thrust upon us by the doctors.
Now you could ask this question, why were the doctors doing this?
A simplistic answer would be, the doctors are doing this because they want to protect themselves legally.
I think that is too simplistic.
These are well-meaning doctors, some of them have gone on to become very good friends.
They probably were simply following the wisdom that has come down through the ages, this adage that when you're making decisions, especially decisions of importance, it's best to be in charge, it's best to be in control, it's best to be in the driver's seat.
And we were certainly in the driver's seat, making all these decisions.
And let me tell you -- if some of you have been there, it was a most agonizing and harrowing experience.
Which got me thinking.
I said, is there any validity to this whole adage that when you're making decisions, it's best to take the driver's seat, be in charge, be in control?
Or are there contexts where we're far better off taking the passenger's seat and have someone else drive?
For example, a trusted financial advisor, could be a trusted doctor, etc.
And since I study human decision making, I said, I'm going to run some studies to find some answers.
And I'm going to share one of these studies with you today.
So, imagine that all of you are participants in the study.
I want to tell you that what you're going to do in the study is, you're going to drink a cup of tea.
If you're wondering why, I'll tell you why in a few seconds from now.
You are going to solve a series of puzzles, and I'm going to show you examples of these puzzles momentarily.
And the more puzzles you solve, the greater the chances that you'll win some prizes.
Now, why do you have to consume the tea?
Why?
Because it makes a lot of sense: In order to solve these puzzles effectively, if you think about it, your mind needs to be in two states simultaneously, right?
It needs to be alert, for which caffeine is very good.
Simultaneously, it needs to be calm -- not agitated, calm -- for which chamomile is very good.
Now comes the between-subjects design, the AB design, the AB testing.
So what I'm going to do is randomly assign you to one of two groups.
So imagine that there is an imaginary line out here, so everyone here will be group A, everyone out here will be group B.
Now, for you folks, what I'm going to do is I'm going to show you these two teas, and I'll go ahead and ask you to choose your tea.
So you can choose whichever tea you want.
You can decide, what is your mental state: OK, I choose the caffeinated tea, I choose the chamomile tea.
So you're going to be in charge, you're going to be in control, you're going to be in the driver's seat.
You folks, I'm going to show you these two teas, but you don't have a choice.
I'm going to give you one of these two teas, and keep in mind, I'm going to pick one of these two teas at random for you.
And you know that.
So if you think about it, this is an extreme-case scenario, because in the real world, whenever you are taking passenger's seat, very often the driver is going to be someone you trust, an expert, etc.
So this is an extreme-case scenario.
Now, you're all going to consume the tea.
So imagine that you're taking the tea now, we'll wait for you to finish the tea.
We'll give another five minutes for the ingredient to have its effects.
Now you're going to have 30 minutes to solve 15 puzzles.
Here's an example of the puzzle you're going to solve.
Anyone in the audience want to take a stab?
Audience member: Pulpit!
Baba Shiv: Whoa!
OK.
That's cool.
Yeah, so what we'd do if we had you who gave the answer as a participant, we would have calibrated the difficulty level of the puzzles to your expertise.
Because we want these puzzles to be difficult.
These are tricky puzzles, because your first instinct is to say "tulip."
And then you have to unstick yourself.
Right?
So these have been calibrated to your level of expertise, because we want this to be difficult, and I'll tell you why, momentarily.
Now, here's another example.
Anyone?
This is much more difficult.
Audience member: Embark.
BS: Yeah.
Wow!
OK.
So, yeah, so this is, again, difficult.
You'll say "kamber," then you'll go, "maker," and all that, and then you can unstick yourself.
So you have 30 minutes now to solve these 15 puzzles.
Now, the question we're asking here is, in terms of the outcome -- and it comes in the number of puzzles solved -- will you in the driver's seat end up solving more puzzles because you are in control, you could decide which tea you would choose, or would you be better off, in terms of the number of puzzles solved?
And, systemically, what we will show, across a series of studies, is that you, the passengers, even though the tea was picked for you at random, will end up solving more puzzles than you, the drivers.
We also observe another thing, and that is, you folks not only are solving fewer puzzles, you're also putting less juice into the task -- less effort, you're less persistent, and so on.
How do we know that?
Well, we have two objective measures.
One is, what is the time, on average, you're taking in attempting to solve these puzzles?
You will spend less time compared to you.
Second, you have 30 minutes to solve these; are you taking the entire 30 minutes or are you giving up before the 30 minutes elapse?
You will be more likely to give up before the 30 minutes elapse, compared to you.
So you're putting in less juice, and therefore, the outcome: fewer puzzles solved.
That brings us now to: why does this happen?
And under what situations -- when -- would we see this pattern of results where the passenger is going to show better, more favorable outcomes, compared to the driver?
It all has to do with when you face what I call the INCA.
It's an acronym that stands for the nature of the feedback you're getting after you made the decision.
So if you think about it, in this particular puzzle task -- it could happen in investing in the stock market, very volatile out there, it could be the medical situation -- the feedback here is immediate.
You know the feedback, whether you're solving the puzzles or not.
Right?
Second, it is negative.
Remember, the deck was stacked against you, in terms of the difficulty level of these puzzles.
And this can happen in the medical domain.
For example, very early on in the treatment, things are negative, the feedback, before things become positive.
Right?
It can happen in the stock market.
Volatile stock market, getting negative feedback, it is also immediate.
And the feedback in all these cases is concrete, it's unambiguous; you know if you've solved the puzzles or not.
Now, the added one, apart from this immediacy, negative, this concreteness -- now you have a sense of agency.
You were responsible for your decision.
So what do you do?
You focus on the foregone option.
You say, you know what?
I should have chosen the other tea.
(Laughter) That casts your decision in doubt, reduces the confidence you have in the decision, the confidence you have in the performance, the performance in terms of solving the puzzles.
And therefore less juice into the task, fewer puzzles solved and less favorable outcomes compared to you folks.
And this can happen in the medical domain, if you think about it, right?
A patient in the driver's seat, for example.
Less juice, which means keeping herself or himself less physically fit, physically active to hasten the recovery process, which is what is often advocated.
You probably wouldn't do that.
And therefore, there are times when you're facing the INCA, when the feedback is going to be immediate, negative, concrete and you have the sense of agency, where you're far better off taking the passenger's seat and have someone else drive.
Now, I started off on a somber note.
I want to finish up on a more upbeat note.
It has now been five years, slightly more than five years, and the good news, thank God, is that the cancer is still in remission.
So it all ends well.
But one thing I didn't mention was that very early on into her treatment, my wife and I decided that we would take the passenger's seat.
And that made so much of a difference in terms of the peace of mind that came with that; we could focus on her recovery.
We let the doctors make all the decisions and take the driver's seat.
Thank you.
(Applause)