Transcriber: Amanda Zhu Reviewer: Rhonda Jacobs
Okay.
Let's start with an experiment.
What color is the letter F?
Some of you might have checked the slide just like I did
to see if there's an F up there.
There isn't.
Some of you might instinctively know what color F is.
What if I told you
that F was the golden yellow color of wheat fields in summer?
Would you think I'd drunk too much caffeine before coming on stage?
Would you think I was just making this up?
Or would you want to argue with me?
Would you be thinking F isn't yellow, F is green, or F is pink?
Some of you might be on the same page as me already,
and if you're not,
then allow me to welcome you to the world of synesthesia.
Synesthesia is a neurological condition,
sometimes called the cross-wiring of senses,
where a stimulation of one sense -
touch, taste, sound, sight -
causes the experience of another.
And the type of synesthesia I've just been talking about,
where F's are yellow or green or pink,
is called grapheme-color synesthesia,
and it's the most common kind.
For people with this type of synesthesia,
graphemes - so letters or numbers -
have colors.
And whilst these colors might differ between individuals,
for the individuals themselves,
they remain the same throughout their life.
These are my personal colors, and they don't change.
Once you've got it, you've pretty much got it forever.
And these are the hallmarks of synesthesia,
and these need to be present
in order for synesthesia of any kind to be diagnosed.
The synesthetic experience must be involuntary,
so it happens whether you like it or not.
And it must be consistent;
it remains the same throughout your life.
It must be unidirectional,
which means that graphemes evoke colors, but colors don't evoke graphemes.
And it must be automatic, so it happens completely without effort.
But today I'm not going to be talking about the most common type of synesthesia;
that would be far too easy -
instead, I'll be talking about synesthesia at its most rare.
Some of you might have had an idea of what I was talking about
when I asked you what color is F.
But what if I had said, What shape is next week?
Well, for one percent of you in the audience -
that's about 10 lucky people -
this should still make perfect sense
because this is what's known as time-space synesthesia.
For people with time-space synesthesia,
time itself has a form,
and this form takes physical shape around the person.
And sometimes this form looks like a hula hoop
or like a roller coaster,
moving through and around the body.
Sometimes it looks more like a halo, encircling the head
and moving as the head moves, or not,
depending on the person.
And these are illustrations by time-space synesthetes themselves.
The science writer Alison Motluk describes her synesthesia
as if she herself was riding a roller coaster,
starting off in January
before moving down all the way through spring and summer,
and then coming back up through autumn and winter
to finish again in January.
And this, as we can see,
is very much a vertically oriented synesthesia,
running parallel to her body like this.
In contrast, the writer Emma Yeomans
talks about a horizontally oriented synesthesia.
So, on a typical working day for her,
she sits firmly in the present with her laptop
whilst to her right, tea steams into her past,
and to her left,
papers and notes cover her future.
And this is much more of a horizontally orientated synesthesia.
But we can see that in both cases,
the person remains at the center of the synesthetic form.
Now, you might be thinking
this is all so far from the reality of how I experience time.
A visible personal calendar that goes with you wherever you go
might sound like something that you have on your phone,
not something that you have in your brain.
But I want to suggest that actually,
when we all talk about time, we use something similar -
we use metaphor.
A metaphor works like this:
you have an abstract concept - let's call it X;
and a concrete concept - let's call it Y.
Now, in this case,
time is the abstract concept while space is the concrete concept.
It's much easier for us to get our heads around space
than it is around time.
Since time is too abstract for the brain to process by itself,
it needs to be given a context.
And by using data
gathered from the auditory, visual, or tactile centers of the brain,
we're able to judge the distance between and the location of events
that happen in time,
giving these events a spatial context.
And so time, X, is mapped onto space, Y.
And by the way,
this mapping is so powerful, so fundamental to cognition
that the act of moving in space or even thinking about moving in space
alters how we perceive time passing.
Studies have shown that just imagining moving forward in a queue
or taking a train journey
dramatically alters how we perceive time in the real world.
And this relationship, of course, is reflected in our language
and this universal rule that time is space.
I bet you've used at least three or probably all of these in the past week.
The deadline has been moved forward
or pushed back;
the time is coming.
Everywhere we look, we run into this rule,
that time is space.
And it's this rule which allows us to create an internal mental timeline.
So how many of you
have spoken about something you wished you'd done yesterday
or something that you want to do tomorrow?
You might have used gestures like this
to emphasize that you're talking about the past or about the future.
All of us in this room, synesthetic or not,
have a mental timeline,
a preference to associate certain areas of our personal space with the past
and other areas of our personal space with the future.
And so, I will suggest that this means time-space synesthesia,
as in the external visual form,
isn't actually a discrete entity;
instead, it's part of a much longer continuum on which we all sit,
where at one end,
the relationship between time and space in the brain
is visualized as an external form
and at the other, it's experienced internally.
Think about it.
This is the axis on which we usually talk about our time.
It runs like this, often through our body,
so we say that we face the future and we put the past behind us.
And we can track this internal synesthesia
with the principles of synesthesia that I mentioned before.
So, is it consistent?
Yes, this doesn't tend to change throughout our lives.
Is it involuntary?
Yes, we can't help that we make these associations.
Is it unidirectional?
Yes, we need to map time onto space because it's so abstract,
but we don't need to map space onto time.
And it's automatic;
most of us don't even know that we're doing it.
So, congratulations, you all have synesthesia.
But you cannot go yet, unfortunately,
because this isn't where the story ends.
Although the relationship between time and space might be universal,
the details of that relationship are highly mediated
by the context and the culture in which our brains develop.
Okay, second experiment.
Imagine that I give you a piece of paper like this,
and imagine that I ask you to draw on that piece of paper
a timeline running from your birth to the present day.
On what side of the paper would you put your birth?
Now, I'm willing to bet that for most of you,
your instinctive answer is that you put it on the left,
with the rest of your life running across the page to the right.
And I'm also willing to bet that for most of you,
your first language, the one you grew up speaking,
runs from left to right across the page.
And my final bet
is that if I'm wrong about your first language,
then I'm also wrong about the placement of your birth,
since studies have shown
that those whose first language runs from right to left, like Arabic,
are more likely to put the event of their birth on the right of the page.
And this means that the mental timeline I was just talking about,
running like this,
isn't universal at all.
It was thought to be for a long time,
but it's recently been discovered
that different cultures visualize time as running along axes
as varied as left to right, right to left, up to down, back to front,
even north to south and east to west.
So here's an example.
The Pormpuraawan are an Indigenous Aboriginal community in Australia,
and if you ask a Pormpuraawan individual
to order photos of a person aging in order from the youngest to the oldest,
they will invariably put the oldest photos of the person on the west
and the youngest photos to the east.
And this is regardless of where they are in the room or their orientation;
they know where west and east is,
and they will order the photos in those directions.
So for the Pormpuraawan, time itself runs from east to west.
And for the Aymara of the Andes,
time runs along a similar axis as it does for us,
but it's reversed.
So the Aymara logic is, well, we've experienced the past -
we know it, we've seen it -
so it should lie in front, where we can look at it,
whilst the future, which remains unknown,
lies behind us.
So for the Aymara,
future events sit here, and past events sit here.
And this is reflected, as it is for us in English, in their language.
So the Aymara word for "last year" literally means front year, or side year.
But I think the most fascinating example of this variation in timelines
comes from the Yupno people of Papua New Guinea.
And the Yupno are geographically isolated by a very steep mountain range,
so their access to lots of Western technologies,
like clocks and calendars,
as well as electricity and domestic animals,
is highly limited.
And the Yupno express their time according to their landscape.
A team of anthropologists living with the Yupno
noticed that if you ask a Yupno person about the past,
they will gesture downhill towards the mouth of the river,
which is so integral to their way of life;
and if you ask them about the future,
they will gesture uphill
towards the peak of the mountain, and the source of their local river.
And again, this remains the same wherever they are in the landscape
and even how far away they are from their local river.
So for the Yupno,
time itself and the flow of time is represented by the flow of their river.
So what implications does this have for synesthesia?
Western time-space synesthete's forms, as you've seen before,
look a lot like clocks or calendars;
they usually run in clockwise or calendrical format around a circle.
But what might these forms look like for time-space synesthetes
growing up among the Yupno or among the Aymara
in a world without access to Western technology?
Well, the simple answer is we don't know,
since synesthesia studies have overwhelmingly focused
on the experiences of Western university students like me,
but we can look at other types of synesthesia for clues.
So there's a variation of time-space synesthesia,
which is called sequence-based synesthesia,
and it looks a bit like this.
So people with the sequence-based synesthesia,
instead of seeing time,
they see strings of numbers as having forms and shapes.
So this is a typical number form of someone with this type of synesthesia.
And in our modern age in the West,
the twists and the breaks that we see in these synthetic forms,
they always happen in intervals of 10 -
so 10, 20, 30, 40 -
and this represents the fact
that in the West, we all live under a very pervasive decimal culture.
Everything is in decimals.
But this hasn't always been the case, not even in the UK.
So 150 years ago, Victorian statistician Francis Galton was doing his research,
and luckily for us,
he was also recording examples of sequence-space synesthesia.
And this is a form that he recorded in 1881 from a British person.
And at first glance,
this form might look pretty similar to the one I just showed you,
and in fact, it has a long stretch here across the middle,
which has numbers ordered in decimal order.
But what's interesting here is where the breaks lie.
And we can see that the breaks lie on one side at 12,
and then at the other side, at 112 and 120,
and this reflects the fact that in Victorian Britain,
the dominant numerical system was the duodecimal system.
And what I also love about this form
is that you can see a perfectly reproduced clock face
just here on the right.
I think it's great.
But the point is that as culture changes, so does synesthesia.
So it's conceivable, even probable,
that people growing up in a culture without Western influence
would display a completely different time-space synesthetic form
to those that we see today in our research,
perhaps even one that doesn't focus on the body
but one that focuses on the landscape,
which as far as we know, has never been seen.
And the likelihood is
that in focusing all of our attention on Western accounts of synesthesia,
we're missing out on an extraordinary range
of cultural and synesthetic variation
that is only paralleled
by the extraordinary range of humans on this planet.
So, beyond being, I think, quite interesting,
why is any of this important?
Well, getting to grips
with this idea of a synesthetic continuum and its amazing variety
could help us to better grasp
how different areas of the brain develop and work together.
Research into brain connectivity has helped us understand so much,
from sleep to addiction to memory,
but we still have a lot further to go.
And I think that launching a dedicated expedition
to the furthest lengths of this synthetic continuum
could help us reveal vital information
about the remaining mysteries of cognitive function.
For example,
synesthesia reveals unexpected connections between different areas of the brain,
so it could easily be used
to help understand how cognitive decline works
and maybe to even prevent it,
or to help patients recover from traumatic brain injury.
And moving beyond science to society,
I believe that truly understanding how cultural differences
can shape this tangible reality that we see around us,
even shaping time itself,
can really help us get to grips
with the concept of seeing the world from other people's points of view.
If we can begin
by dispensing with this outdated idea that we have rigid sensory borders
and instead, come to accept that we all sit somewhere together
yet at separate points on a continuum of experience,
then perhaps we can take one step closer
towards dispensing with unnecessary social divisions altogether.
And maybe that might even mean one step further
towards inhabiting a world
that is extraordinarily and joyfully unbound.
Thank you.
(Applause) (Cheers)