What is the Mind's Eye? The Science of Imagination, Aphantasia & Consciousness | Adam Zeman

What does it really mean to see with the mind’s eye?In this conversation, neurologist and consciousness researcher Professor Adam Zeman (Cognitive & Behavioural Neurologist, University of Exeter) joins Dr Tevin Naidu on Mind-Body Solution to explore the mysterious link between imagination, memory, and perception - and what happens when the mind’s eye goes dark.Zeman coined the term aphantasia, the inability to form mental images, and has spent decades studying how imagination shapes our sense of self and consciousness. Together, we discuss:- The neuroscience of mental imagery and its vividness- What aphantasia and hyperphantasia reveal about the brain-mind interface- Imagination’s evolutionary and social roles- How disorders of imagery illuminate the nature of consciousness- Why defining "inner experience" remains one of science's deepest puzzlesTIMESTAMPS:(00:00) - Introduction: Why imagination matters and the four big ideas(02:14) - What do we mean by “imagination”? Everyday vs scientific senses(05:46) - How imagination is implemented in the brain: top-down vs bottom-up processes(09:08) - The phenomenology of imagery: vividness, aphantasia, hyperphantasia(12:58) - Aphantasia explained: discovery, definition, and how common it is(16:50) - Measuring imagery: questionnaires, behavioral tasks, and limitations(20:30) - Dreams vs wakeful imagery: why people without imagery often still dream(24:12) - Aphantasia and memory: effects on autobiographical recall and learning(27:54) - Hyperphantasia and creativity: strengths, tradeoffs, and examples(31:28) - Clinical cases & the TIME project: epilepsy, transient amnesia, and memory links(34:50) - Accelerated long-term forgetting: what it reveals about memory consolidation(38:12) - Disorders of visual imagery: aphantasia, prosopagnosia, and related syndromes(41:55) - Therapeutic and performance uses of imagery: sports, music, psychotherapy(45:20) - Objective neural markers: fMRI, activation of visual cortices and network differences(48:56) - Assessing imagery in the clinic: best practices and pitfalls(52:30) - Imagination and consciousness: philosophical implications for “life in the mind”(55:50) - Language, sharing imagination, and why we evolved communicative imagination(59:38) - Dementia, PRESIDE and clinical relevance: early markers and research directions(01:03:50) - Future directions: AI, computational models, and bridging phenomenology + neuroscience(01:07:30) - Closing reflections: practical takeaways for researchers, clinicians, and curious minds EPISODE LINKS:- Adam's Website:- Adam's X: https://twitter.com/zemanlab- Adam's Publications: https://scholar.google.com/citations?user=7BSh2mQAAAAJ&hl=en- Adam's Books: https://www.amazon.com/stores/Adam-Zeman/author/B001H6UT84?ref=sr_ntt_srch_lnk_1&qid=1760539071&sr=8-1&isDramIntegrated=true&shoppingPortalEnabled=true- Science of Imagination: https://www.youtube.com/watch?v=lkYwKjkCJgECONNECT:- Website: https://mindbodysolution.org - YouTube: https://youtube.com/@MindBodySolution- Podcast: https://creators.spotify.com/pod/show/mindbodysolution- Twitter: https://twitter.com/drtevinnaidu- Facebook: https://facebook.com/drtevinnaidu - Instagram: https://instagram.com/drtevinnaidu- LinkedIn: https://linkedin.com/in/drtevinnaidu- Website: https://tevinnaidu.com=============================Disclaimer: The information provided on this channel is for educational purposes only. The content is shared in the spirit of open discourse and does not constitute, nor does it substitute, professional or medical advice. We do not accept any liability for any loss or damage incurred from you acting or not acting as a result of listening/watching any of our contents. You acknowledge that you use the information provided at your own risk. Listeners/viewers are advised to conduct their own research and consult with their own experts in the respective fields.

Episode Transcript

(00:08):
Adam, you work within very diverse fields and you've
managed to bring them all together.
Neuroscience, evolutionary biology, psychology, there's,
there's so much we can discuss. But something I've written down,
which is a quote of yours, you said that what sets us apart is
a life in the mind, the ability to imagine.
Perhaps we could begin by you explaining what do you mean by

(00:31):
that? And what does it mean to live a
life in the mind? So, like many people, I've
always been fascinated or long been fascinated by the question
of what sets us apart from othercreatures on Earth, if, if
anything, does. I mean, I think this interest
goes back to my undergraduate days.
And it struck me over the years that a very strong candidate is

(00:52):
our capacity to detach ourselvesfrom the here and now, recollect
the past, anticipate the future,enter and create the virtual
worlds of science and art. So broadly, the the achievements
of the imagination. And that's what I, what I had in
mind. That quotation is in fact from
Robin Dunbar. It's Brian Dunbar, as you, I'm
sure you know, is an anthropologist who's very much

(01:14):
interested in the same question.And I think his, his thoughts
and mine have converged on the same conclusion that that the
imagination is a is a strong candidate for the the source of
human uniqueness, such as it is.Do you see imagination not
merely as a creative faculty, but as the very medium through
which all human experiences takeplace?

(01:35):
Yeah, so that's a great question.
And I guess it prompts me to saythat one of the difficulties in
thinking and writing about imagination is that it's clearly
not not a term of science. It's a kind of slippery,
slippery term which we use in a number of different ways.
So it may be worth teasing threeof those apart at the outset.
Perhaps we'll work backwards because I think the, the, the
sense of imagination that we most often use colloquially is

(01:57):
what's been called productive imagination, I think by William
James. So that's the, the ability that
underlies our creativity, our capacity to make things that are
both new and, and useful. And that's a rather, we'll come
back to this. It's a rather special sense that
the second sense, which I think is, is in a way core is what's
been called reproductive imaginations.

(02:19):
That's our ability to represent things in their absence,
typically using their sensory properties.
So if I ask you to imagine an apple or imagine your, your
front door or your, your or yourpartner, you'll probably be able
to call to mind the sensory features of apple front door,
door partner. But but look the appearance.

(02:41):
And when you do so, you are, you're engaging in reproductive
imagination of a of a sensory kind.
And I think that that's that's avery colloquial sense sense of
imagination. There's a third sense, which is
less but colloquial, but which you pointed to in your in your
question. Psychologists will occasionally

(03:01):
speak of the the retinal image or the perceptual image.
So that's our immediate experience of a here and no.
And the fact that we can use imagination in that sense, even
if it's not terribly colloquial to do so, reminds us that our
moment to moment experience is acreative act.
I think it's fairly clear that there's a kind of creativity

(03:21):
involved in reproductive and productive imagination.
It's less obvious that there's acreative act involved in our
moment to moment experience, butthere are very good reasons for
believing that there is, and those reasons range from the
psychological. So illusions provide an example.
In the book, I have an image of my partner in fact running over

(03:42):
a bridge and the the same imagesreproduced at several different
distances and she looks much bigger in the distance than she
does in year 2 because your mindmakes an automatic correction
for distance. So that that's a slightly
sophisticated example of the theworkings of the mind in
perception. More obviously, when you look at
the moon and you see the the manin the moon, you're engaging in

(04:04):
peroid earlier. You're you're imposing a pattern
that doesn't exist there. I have a personal teenage
example of waking in the night to see a burglar standing at the
foot of my bed wearing a stripedfootball shirt.
I was terrified. I shouted at him, and over the
next two or three seconds, the image dissolved into a pattern
of light shining through a slatted fence.
So there's a psychological examples of so that's I'm

(04:28):
providing some psychological evidence for believing that
perception is created, but there's also the more
straightforward neurological evidence.
Our experience depends entirely on the activity that's occurring
in our heads, consuming oxygen and glucose every every moment
of our lives. So there are these, I think,
these three senses of imagination, one which I think
is not very colloquial but but is philosophically very

(04:49):
interesting, that the sense thatreminds us that there's
something imaginative about perception itself.
Then there is the the reproductive imagination, our
capacity to, for example, visualize the knuckle in our
mind's eye. And then there's the productive
imagination, our ability to create things which are both new
and useful. And coming back to something I,
I hinted at earlier, it's curious that we use that the

(05:10):
same term for both the productive and the reproductive
imagination. And I guess it has to do with
the fact that many creative people use imagery in their
creative thinking. But we don't have to.
And one good reason for thinkingwe don't have to is that people
who have Fantasia, which I'm sure will come on to discuss
people who lack sensory imagination, can be highly

(05:31):
productive and imaginative in that more general sense.
So sensory imagery is not required for creativity, but
it's often involved in the process.
I'm glad you touched on that because often when I interact
with patients, I noticed that when it comes to imagination,
many people still associate imagination with with fantasy or
childlike childish make believe.Why do you think this is so?

(05:53):
Why do you think imagination remains so misunderstood, even
though it's so pervasive in ordinary experiences?
Yeah, well, I suppose the, the imagination is, is a kind of
gift and a curse. And it can, it can mislead us.
It can it can take us into realms of unproductive fantasy.

(06:15):
There's there's the recently described syndrome of
maladaptive daydreaming. People spend far too much of
their lives lying on their couchor in bed dreaming about what
might be. So that's a, that's a rather
unproductive use of the imagination.
And that's one, one of one of the connotations of imagination.
But, you know, I think people, people generally regard the

(06:38):
imagination as a good thing. In fact, one of the, one of the
reviews of my book said just just that.
And we described Dickens or Tolstoy as highly imaginative
writers. And, and, and, and when we when,
when we use the word in that way, we're commending them.
So it's, it is pluses and minuses for sure.

(06:58):
You know, I think, I think it isin in many ways the source of
our human uniqueness, but it canalso be a be a problem for us.
Your, your book's titled The Shape of things unseen.
Wonderful read a beautiful book,so descriptive.
And one of the things I was thinking about when when you
wrote this, as I read about Ephantasia, which you briefly
just touched on and we'll definitely discuss soon as we

(07:21):
just spoke about this earlier. But when I was writing my
dissertation, I'd quoted some ofyour work and had no idea who
you were at the time. This was many years ago.
And it, it's so great to finallyput a face to the name.
And, and in a case like that, I think it's perfect that we're
talking about this, this puttinga face to the name or trying to
imagine the person you're, you're thinking about or writing

(07:43):
about when you discovered this. Because when I started Med
school, this was about 2011, this concept at Fantasia, this
term did not exist. However, we learn about it, it's
very indirect. We speak about it.
Certain things that are similar,like prosopagnosia, we've got
all these terms and all these similar phenomenon.
And then once I'm tundered bits called 2016 onward, suddenly

(08:04):
this new concept exists. What is it like to almost
rediscover but discover something so unique?
And what's the journey been likesince then?
So it was very serendipitous this this discovery or or
rediscovery as as you as you imply, I must say it's been

(08:24):
enormous fun. It just happens that this
stumbling upon this phenomenon seems to have unlocked a huge
number of really fascinating avenues for exploration.
Maybe we'll I'll tell the story in a little more detail later.
But the I think that the trick in a way related simply to the
creation of a word. So the clearly people must have

(08:44):
existed who lacked a mind's eye,lacked sensory imagination, you
know, since time immemorial, butthey, they didn't have a flag
to, to fly under, so, so to speak.
And because I encountered a number of people who were
describing this phenomenon, it became clear that it it would be
helpful to give it a name. And I consulted an old
classicist friend who suggested that we borrow Aristotle's term

(09:07):
with the mind's eye Fantasia andtagged on an A, hence a
Fantasia. And, and the term caught on the,
the press liked it. So it, it got an airing.
And I initially had a wrote a paper describing a group of 21
people of Athantasia. The number of contacts turned
into 20,000 over the course of the next few years.

(09:30):
And yeah, it's been, it's been, it's been a delight.
It's been, it's been very exciting and unexpected.
Let's try and dissect that a bit.
So what is the mind's eye? For anyone who's not familiar
with that phrase, where does it come from?
What does it mean firstly, and then let's move on to what a
blinds a blind mind's eye would be, or an athentic mind.

(09:51):
So I think the mind's eye is actually a Shakespearean phrase
and it and it refers to our ability to visualize.
So most people, if you ask them to call to mind an apple, their
front door, the the face of their partner will will be able
to do so. And we'll have an experience
that is at least weekly visual place quite a big part in in

(10:13):
autobiographical memory for mostpeople.
So if I ask you to remember a day from your last holiday, the
most memorable day from your last holiday, most people will
again have an experience that's somewhat visual.
They'll be able to remember the look of the place they were in,
the look of the people they werewith.
There may be more to it than visual recollection.
So they might be able to remember sounds or touches or

(10:35):
the OR the feel of the of the experience.
So that is, that's what's meant by the mind's eye, by sensory
imagery. And as I say, most of us possess
sensory imagery, but we seem to vary, vary widely in the
vividness of that imagery. We've used a scale called the

(10:56):
vividness of the image, your questionnaire to try to, to, to,
to get a handle on this. So that invites you to visualize
16 scenarios. For example, you're watching
the, the sun rising above the horizon into a hazy sky.
Again, most people when they do that will have an experience
that's somewhat visual. You can then rate the vividness
your, your image from A5, which means as vivid as real seeing.

(11:17):
And about 10% of people say their imagery is like that to
A1, no image at all, just thinking about it.
And that's the that's the situation for people who like a
mind's eye. So there's, it turns out to be a
group of people, probably about 4% of the population, depending
where you draw the line, who when you give them that sort of
exercise, say, well, you know, I, I know about apples, I can

(11:37):
recognise apples. I know about sun, sun's rising
over the horizon. I can think about them perfectly
well, but I didn't see anything.And typically people who like a
mind's eye will for a long time assume that when others are
speaking about visualizing aboutthe mind's eye, they're, they're
just using words in a purely figurative, metaphorical way.
But then at a certain point theyrealized that actually people

(12:00):
are having an experience which is somewhat visual and and which
they they never achieve. Our work was a kind of
rediscovery rather than a a a brand new discovery because
among others, Francis Gorton, 19th century psychologist who
was the first person to devise aa questionnaire to quantitative
imagery, had noticed that there were some people whose power

(12:22):
visualization was zero, as he put it.
But no one really had focused onthe interesting folk at these
extremes of the of the of the vividness distribution.
It turns out that we focused initially on visual imagery, but
it turns out that most people who are fantasic actually like
sensory imagery more widely, so it isn't usually an isolated

(12:43):
visual phenomenon. Generally they don't have much
of A mind's ear or a mind's fingertip either.
And the idea of imagining spellsand tastes is, is very an alien
to them. And there is a kind of
interesting pattern of associations.
So often people with that Fantasia have difficulty
recognizing faces, not always, but but quite often.

(13:04):
They very typically say that theautobiographical memory is
rather thin, rather factual. They don't have that capacity
for mental time travel, for re experiencing the past, reliving
the past that that many of us have.
There's an association with autism in some folk.
Really interestingly, most people that Fantasia dream
visually. So there's a fascinating

(13:26):
dissociation between wakeful imagery and dreaming imagery.
So most people that Fantasia know, know what it's like to to
visualize because they do so very vividly in their dreams.
They just can't make it happen during wakefulness.
So that's a that's a kind of thumbnail sketch of a Fantasia.
I think it's born Adam at this point, for anyone who's watching

(13:47):
and listening, trying to figure out exactly how is it possible
for someone to even prove this or show this.
You have a you have various different techniques and ways to
do this. One of them being for someone to
imagine the a face of someone orlight, let's say allow the
people to constrict or or or dilate.
Do you want to maybe run through?
You don't have to go through in detail, but at least a few ways

(14:07):
that people can understand exactly how this is tested,
improved. Sure.
So, so one reaction to the findings I've just been
describing might be doubt skepticism on the grounds that
it's very difficult to know whatsomeone else is experiencing.
And how can you be sure that thedifferences that I've been
highlighting aren't simply different ways of describing the

(14:29):
same kind of underlying experience?
And I think there are a number of reasons now for thinking that
the differences that people are pointing to, the introspective
differences are pointing to, aregenuine, are real.

(14:51):
It's helpful, I think, to think of a kind of triangulation
between first person reports, measurements of behaviour and
physiological measurements. So what do I mean by
measurements of behaviour? Well, it is possible to measure
the richness of people's autobiographical memory.
There are quite well developed techniques for doing that, like
the autobiographical interview developed by Brian Levine in

(15:13):
Toronto. And now a number of groups have
shown that when you ask people with a Fantasia or
hyperphantasia, very real imagery to describe their
salient memories from their personal past, people that
Fantasia give much less rich descriptions than people with
with hyperphantasia. So that's a psychological
measure. Then turning to the
physiological measurements, a very nice experiment.

(15:37):
It's not, it's not my technique,but but a nice, a nice technique
that's been applied to aphantasia and adventasia
involves the pupils. So if of course, if you look
into the sun, your pupils will constrict.
If you look into a dark room, your pupils will dilate.
It turns out that if you have aphantasia, you don't see those.
I'm sorry, I've missed a step. If you look into the sun, your
pupils will constrict. Look into a dark room, you will

(15:58):
dilate. If you have imagery and you
imagine looking into the sun or into a dark room, your pupils
behave in the same way. Constrict dilate, if you have
athantasia, you don't see those stripillary responses.
Another nice example involves measurement of the galvanic skin
response, essentially sweating. When you read people really
scary stories. And this is this is work from

(16:21):
John Pearson's group in Sydney. And they showed that normally if
you read such a story to somebody with imagery, they will
there will be a change in their GSR and it'll sweat a little.
And these are quite scary stories.
So you imagine you're, you're lying in the sea on a balmy day.
There's a nice chatter of conversation from the beach.

(16:42):
You're, you're just letting yourself float in the water.
And then conversation works. You look up and you see that all
the heads are turned towards youand you look over your shoulder
and you see a fin advancing and things go from bad to worse in
this story, certainly it made mesweat a bit.
And turns out the people that Fantasia don't have that
galvanic skin response. And they performed the nice

(17:06):
control experimenter showing people that Fantasia scary
pictures to which they do show the skin response.
So it seems to be that lacking imagery prevents the the gut
response, if you like, because imagery mediates between the
verbal description and the autonomic visceral response.
Helps to explain why people thatFantasia don't often don't enjoy

(17:27):
novels very much. They don't enjoy descriptive
writing very much. And then most directly of all,
there's now been worked looking into the brain, and it does seem
there are differences in the brain between people with
imagery and without imagery. I'll give a couple of examples.
So I think we did the first study of this kind a few years

(17:48):
back now. And in that study, we looked at
resting state fMRI. So you just ask your
participants to lie in the scanner and chill.
This is a wonderful technique. You can use it to pick out all
the networks of the of the active brain because they
continue to tick over when, whenyou rest.

(18:09):
And it seems that people with vivid imagery have stronger
resting connections between areas at the front of the brain
that were basically involved in thought and areas at the back of
the brain involved in vision andpeople that Fantasia.
So helping to explain why thought would translate itself
more readily into imagery in in people with their imagery than
people lacking it. And then more recently there's
been, there've not been, there've been a number of

(18:31):
studies, rain imaging studies over just over the last year,
but one of them from Yanghao Liuin, in Paris has shown that
although you do see many of the same kinds of visual activation
in people without Fantasia when they try to imagine that
activation is less well coordinated, less well
integrated, less widely broadcast in the brain than in

(18:53):
people with imagery. So there are, there is, if you
like, a neural signature for, for aphantasia.
So you can you can triangulate between first person reports,
behavioural measures and physiological measures in in
quite a satisfying way, which I think helps to meet the the the
skeptics reasonable doubts aboutaphantasia.

(19:15):
I think it's, it's particularly fascinating because I was
speaking to a friend about this,telling them I'm, I'm about to
chat to you the, the fascinatingwork that's been done.
And I tried to explain exactly what aphantasia is.
And the moment I mentioned it toher, she said, oh, shame and
that there must be such a difficult life.
And I said, no, no, not really. Because a lot of these people

(19:37):
are creative. They don't even know they have
this problem. They're living life completely
normal. So it's not necessarily an
abnormality, it's just atypical.Do you have anything to comment
on that? Yeah, absolutely.
And I think that's that's in a way one of the most interesting
and surprising things about Eventasia.
So often when people first hear about it, as you say, they they

(19:57):
kind of react well, how can they, how can they remember?
How can they think? And Athentasia, although it
makes AI think a big difference to people's inner lives, makes a
surprisingly small difference totheir performance.
And that is? Puzzling and intriguing.
I think it proves that Aristotlewas wrong when he when he wrote

(20:20):
in Diana mirth. The soul never thinks without a
phantasm. Clearly you can you can get by
without much in the way of sensory imagery, it reminds us
that there are a number of ways of representing things in their
absence other than sensory imagination.
Language does does pretty well all the forms of other forms of

(20:41):
of of notation that we use, for example, mathematical notation.
And clearly it's possible to be creative, productive,
imaginative in that broader productive sense in the absence
of imagery. So we have numerous examples
now, including Ed Catmull, the past president of Pixar isn't
who won the Turing Prize for hisdiscoveries, discoveries in

(21:01):
computer animation. Or Craig Venter, who was the
first person I think to decode the genome, who's attributed
some of his scientific prowess to the fact that his mind is not
cluttered by imagery. So I I don't think of aphantasia
as a disorder. I think of it as an intriguing
variation in human experience. And I think it has got pluses
and minuses like imagination itself.

(21:21):
So people with aphantasia often do regret that they can't
visualize the face of a departedfamily member, for example, or
see their girlfriend in in her absence or visualize last last
year's holiday. But it may be that they're
somewhat more present, a bit less troubled by longings and

(21:41):
regrets it Athantasia seems to nudge people in a in a
scientific direction, a little bit more likely to be working in
stems. So there may be some advantages,
cognitive advantages to to Athantasian.
And the other thing to say is that although I think it's very
fascinating, it is of course just one small piece in the much

(22:04):
in the huge jigsaw of human cognition.
So of course there are all sortsof other influences in play in
any individual psyche. And curiously, Athantasia
doesn't even preclude things that you might assume it would
rule out, like being a creative visual artist.
So one big surprise to us early on was that we were contacted by

(22:26):
a growing number of Athantasic artists.
I must have absolutely got over 100 contacts now in my in one of
my files we put together a an exhibition of art by Athentasic
and hypophantasic artists. And many of the Athentasic
artists said, you know, it's actually a stimulus to me to
create because I can't, because I can't see things in my mind's
eye. And I love the visual world I
want to recreated. And it's such an unfathomable

(22:48):
thoughtful for people who don't have this lack of experience
because to us, it's, there's only one way we can perceive
reality. And that's the way we've been
given or, or the way we can perceive it.
Because I was watching that clipthat you played in your Royal
Institute lecture of Little Mermaid and the way he was
painting, the artist is paintingthat and it, and it's
incredible. You can see that there's
something different happening versus the way we would paint.

(23:10):
And it's fascinating to watch that.
So this, this is Glen Keane, who's a, who's a Disney artist,
apparently a well known animatorwho has says he's had many
arguments with his colleagues. They say, but you must be able
to, to visualize. And he says, no, I, I know what
I want to draw and I, I draw it.I can't see it beforehand.
Your work, it's it's been pioneering work.

(23:32):
So this first part of the conversation, I tried to lay out
the landscape of imagination. You were pioneering work in
aphantasia, hyperphantasia, thisabsence of overabundance.
They illuminate sort of a hiddendiversity of inner experience.
And just a few days ago I was speaking to Russell Hilbert
about exploring inner experienceand the fact that he he was has

(23:56):
what's descriptive experience sampling.
And he shows how the inner monologue doesn't exist the same
way we perceive it. And I've been finding these last
few weeks exploring this with different people, it shows how
diverse this experience is. What do you think that these
diverse experiences really reveal about consciousness
itself? Yeah.

(24:18):
Well, yes, I'm glad you mentioned Russ because his his
work, it's a scripted appearancesampling has been has been
pioneering. Well, I said at the beginning
that imagination was was one of the hallmarks of human
cognition. I guess the second hallmark is

(24:39):
difference and that I think reflects our, our neural makeup,
You know, 80 what is it 86,000 million cells in the brain on
average several 1010 thousand connections between for each

(24:59):
neuron. So just a vast storage space for
difference. And we know now that learning
and memory are at least to a fair degree coded in differences
in the, in the strength of, of connections between neurons at
those synopsis. So I think it's, you know, it
shouldn't surprise us that we have very different inner
worlds. I've I was struck while I was

(25:24):
researching for the book and speaking to people who are
highly productive in different fields that they have trained
their brains in such a way that they can kind of switch, switch
their creativity on and off their their their, they've
programmed their brains to be creative in their in their
particular domains. But the, the programs that have

(25:46):
running must be very different to produce, to produce an
entertaining novel versus a theory about the first few
moments of, of, of creation. And I suspect that one of the
reasons that hit that the past strikes us as a foreign country
is the related one that the brains of people, you know,

(26:08):
100,000 years ago were, were very different to us.
So I'm not sure I quite answeredyour question, but I think I
think the the presence of these invisible inner differences
makes sense given what we know about the nature of our brain
and its vast capacity for encoding, encoding difference.

(26:32):
What's tell us about about the science of consciousness or I
mean, I guess it's an article offaith for most people who who
are interested in problem of consciousness.
Not all, but most of that differences in experience
correspond to differences in thestructural function of the
brain. And I think we're exploring
those differences through this kind of work.
The the first part I tried to lay out the landscape of

(26:55):
imagination. What I'd like to do now is just
go into perception as imagination, because in your
recent book you argue that even our experience of the here and
now is itself imaginative. So could you unpack that idea?
In what sense are we imagining the present moment?
Yeah. So we touched on this at the

(27:16):
start. So I'll, I'll maybe run over
some of that ground again and and in a little more detail.
So when we open our eyes and look at the world, it seems that
it's just there for us. There's there's no effort
involved in looking at the garden that outside the window.

(27:37):
I don't have to, I don't have todo any work to to, to, to bring
it into being. But that sense of ease is, I
think, very deceptive. I think the world as we perceive
it depends on creativity within our within our brains on a kind

(27:58):
of generative act relies on a vast store of accumulated skill
and knowledge which which is invisible to us most of the
time. But there are a number of ways
that we can make it somewhat visible.
So illusions provide one example.

(28:19):
We there are numerous wide rangeof illusions which show us that
what we see, what we perceive doesn't always correspond to
what's there. And often and illusions are
explained by the fact that we are making unconscious
inferences. So I gave you the example of a
size distance illusion. If you see the same image

(28:39):
superimposed on a photo close and far, it will look larger in
the distance because your brain,your mind, mind, brain pixel
unconscious compensation for thefor the distance.
Francis Bacon in the 16th century said that sense passes
over to imagination before reason has judged.

(29:02):
And I think he was producing a very modern foot.
Essentially the the idea that Helmholtz developed in in the
19th century. That perception involves a great
deal of unconscious inference. So illusion provides one
example. I, I mentioned pyroid earlier.
We often see forms where there are nuns.

(29:23):
So, you know, I don't like spiders very much.
I often look down at the ground and see a see a spider, which
turns out to be A twist of twistof cotton.
My, my slightly anxious spider fabric mind is, is, is
projecting spider wherever there's a, a shape that might
just be 1 if you like. I'm predicting spiders where,

(29:45):
where there are none. So the, the line of thought
which I'm pursuing here meshes with the idea of the predictive
brain, which I know you've I'm sure you've discussed with
others. I know I see that Carl Friston
has has been one of your interviewees.
And then I guess at the extreme hallucination provides a a very

(30:08):
compelling example of the creativity or generativity of of
the sensory brain. So in states of hallucination,
people perceive things that aren't there at all, as if they
were out in the world. And I give numerous examples in
the book. In one one commonplace, slightly
sad, but but commonplace exampleis a brief, brief and
hallucinations. So people who've lost a partner,

(30:32):
more often than not, we'll experience the presence of the
partners sometime over the over the following months.
Feel a touch, see the, see the look, hear the voice of that
person clearly. You have a tremendous, your
brain is going to make a tremendously strong prediction
that somebody who's been with you for many decades will still
be there. And occasionally that prediction

(30:55):
produces activity in the brain that rises above a certain
threshold and you, you perceive the presence of, of someone
who's, who's no longer there. So there are many, there's a
good deal of psychological evidence for the, the
generativity, the creativity of,of perception.

(31:17):
I think the, the neurological evidence is in a way more, more
straightforward. So it's kind of eerie, isn't it?
We don't, we don't most of the time reflect on the fact that to
be doing anything at all, our heart has to be beating and our
lungs have to be have to be working for us.

(31:38):
But to enjoy any moment of experience, our brains have to
be active. We, we know that we know that
our brains are dynamic, energy consuming, active in a sense
autonomous organs. Your brain at the moment will be
consuming roughly the amount of energy that you need to run a 20

(32:00):
Watt bulb, burning oxygen, burning glucose.
If you deprive it of it, the oxygen and the glucose
experience ceases. So for all those reasons, I
think it's, it's clear that experience is a, a kind of
generative act. It's been described by Chris
Frith, among others, as a, as a controlled hallucination.

(32:23):
So in a sense, we hallucinate hallucinating the world around
us all the time. But most of the time,
fortunately, the hallucination that we experience corresponds
with the reality that lies beyond.
How do we know? Well, because we're here, we,
we're, we're grappling with thatreality successfully.
We, we've evolved and we survive, but we have no access

(32:44):
to that, no direct access to that world around us except
through our experience, of course.
That experience, I think, is nota I think there's overwhelming
evidence that experience is not a kind of direct readout of the
world around us. It's it is something like a
controlled hallucination. Yeah, I think it's A to me,
that's one of the most fascinating things about
experience is that the more you learn about it, the more you

(33:06):
realize that our naive realism towards realities, it it's so
apparent. And and I remember when I wrote
about this, I was it's it's almost like it's it's like
breaking free. It's kind of like realizing that
this is not what we think it is.You mentioned people like
Kristen Seth, all these people who are working on this

(33:27):
controlled hallucination, all these Bayesian brains, these
frameworks that sort of show that we're more like prediction
machines rather than experiential system, seeing
things as they are. But it was something I wrote
down while reading your work wasif perception is imagination
constrained by sensory input, could imagination then be seen
as perception freed from those constraints?

(33:55):
Yes, I think in a sense it can, but but but there's AI think
there's a missing step there. It'll be interesting, I guess,
for those listening to this to know that when we imagine an
apple, imagine a face, imagine asound, we, there's no very good
evidence that we activate the brain regions that we would

(34:19):
activate were we actually looking at that face, at the
apple hearing the sound. So when we, when we engage in
sensory imagery, we are running offline the systems that we use
to perceive the world online. But yes, as you say, imagination
frees us from some of the constraints imposed by by

(34:41):
reality and it allows us to produce virtual imaginary worlds
as as a result using the material which which perception
has previously supplied by by enlarge.
Yeah, I think it's it's it's quite a cool thing to think

(35:03):
about because then it philosophically raises the
deepest question of all if, if perception is itself
imaginative, then does that blurthe distinction between what is
real and what is imagined? And yeah, I guess that's one of
the puzzling features of realityis that we might never know what
the fundamental veridical natureof reality is.
I think it very much blows that distinction.

(35:24):
Absolutely. I mean, that's not, that doesn't
negate the distinction between reality and unreality, because
there's a difference between a controlled and an uncontrolled
hallucination. But no, absolutely.
I, I, I think that's a very profound philosophical point

(35:45):
too. Too profound for.
Yeah, I think, I think in reality, in the sense we should
be clear means consensus reality.
Yeah, yeah, yes. And it's, I think there are,
there's both consensus among individuals and, and also the,
the, the evidence from evolutionand survival that, that we're,

(36:09):
that we're, our perception of the world is good enough.
Our experience is is is doing its job.
Yeah, I think when I read your work, Adam, someone who you
remind me of is Oliver Sacks where very similar.
So neurologists exploring the deeper philosophical picture
with a deep appreciation for thepatients experience, the lived

(36:32):
experience as well as the science.
Do you see that that's fundamentally your goal in life
is to explore this with that feature?
I absolutely do and I'm very flattered by the analogy of
sucks because he he was very much a hero and someone I read
as I was training in urology. So great, the great inspiration
and I think a wonderful writer would love to write as as well

(36:54):
as he did. But yeah, I, I absolutely see
that as my, my mission in a way to try and bring together the
subjective and the objective aspects of, of neurology and,
and neuroscience. In fact, I think that's what
doctors are doing all the time. You know, we're constantly
hearing stories from patients and we're trying to map those

(37:16):
onto a scientific understanding of, of the body and then to
translate back. So, you know, for the patients
who kind of explain their experiences to them in terms of,
of Physiology and, and pathophysiology.
So in a way, journalists, I think in a way doctors I think
have to be rather like journalists kind of translators

(37:37):
moving between those two, those two realms.
Some doctors are, are real scientists, but not very many.
Some are but but all of us, all of us have to have to move
between those those two domains.Yeah, I agree.
I think that as, as medical doctors, when you encounter a
patient, you get to see it via 2lenses.
The, the objective third person scientific experience as well as

(37:59):
the first person subjective phenomenal experience, which is
great because you get to then try your best to correlate as
best as we can. And I often found that that's
exactly what Sax did back in theday.
He was he was a neurologist who behaved like a psychiatrist as
well as a philosopher, which is a a beautiful way to I think he
wrote a book, The Mind's Eyes for Normal Sake.

(38:21):
Yeah, and in fact, he was, he was authentic.
He he got in touch with me not long before he died.
Oh, wow. Adventic.
But had a reasonably vivid mind's ear.
And he was, he was Prosper Agnoisic.
I think. By the way, it makes you a
better doctor, doesn't it? True to bear in mind those two
elements of your work because you don't want to get too lost

(38:42):
in either domain because it really is your job to to remain
attuned to people and their experiences and to the science
that's. I'm, I'm a huge SAX fan.
In fact, those colourful books, these, these colourful ones on,
you know, all Sax's books in a row just.
I turned the turned the camera alittle.

(39:03):
You'd find the same, the same one.
My show. He he was a wonderful writer.
Yeah, I know. Beautiful writer.
He's he's actually the person who got me into being a doctor
in the 1st place. I remember reading his book as a
child. I think it was the The Man Who
Mistook His Wife for a hat, and I remember thinking this is
something I would do if it wasn't for astrophysics.
That was the next best thing, and it was his writing that
actually got me into it. And it's thingy, over time I

(39:24):
think he became more and more attuned to science, didn't he?
I think, I think he was a bit ofa rebel initially and he was
kind of going against. He worked dyke and just chilly.
Yeah, he was quite rebellious. Yeah, but he sort of moved more
into the mainstream as as time went by.
Well, on that note, moving towards science, let's now move
into the science of the imagination.
So at this point, let's discuss the neural systems and shared

(39:45):
meaning. Your book explores imagination
in scientific terms and and one of them was running the mind
offline. How literal is that?
Is imagination just the brain rehearsing action perception
loops in a simulated mode? I think to some extent that's a
fair, a fair description. So clearly if I ask you now to

(40:08):
imagine an apple in your line's eye, you're going to have to do
a wide range of things. You're going to have to
understand what I'm saying, engage so engaging language
systems. You're going to have to remember
what another looks like. So you're going to have to draw
on memory. But it seems that to have an
experience with a visual feel, you then need to use the

(40:30):
information stored in memory to drive your visual system or to
drive your sensory systems from top down.
And so sensory imagination to bedescribed as an echo of
perception or as as weak perception.
And I think, I think that's fairenough.
There's no very good evidence from brain imaging that when we
visualize, we do indeed activatebrain regions and we activate

(40:51):
them in a stimulus specific way.So if you imagine the face,
you're going to activate your fusiform face area, which you
know is is very important for recognizing faces.
If you imagine the sound of Thunder, you're going to be
activating auditory regions. So so yes, I think that sensory
imagery does indeed depend on combination of activity in front

(41:16):
parietal regions, which kind of control your your cognition.
So you have to make to imagine that I believe you'd have to
make a decision that that's whatyou want to do.
You'd have to organise your reign to do that, but then to
have the sensory experience associated with the image of the
output, you'll need to activate those those sensory regions top
top down. The the default mode network is

(41:39):
often associated with imagination, mind wandering,
autobiographical thought. What role do you see this
network playing in shaping our world?
Yeah. So I'm sure that those listening
for Brigham will know that thereare a number of networks
involved in in cognition, some of which studies of the resting

(42:02):
brain have have revealed. The form of network is
particularly fascinating network.
In case anyone doesn't know about it, this is a network of
regions which is which is particularly acted in the
resting brain. So it's it's level activity is
higher in the resting brain thanwhen you engage people in a when
you impose on people an externaltask.
It involves a variety of regionson the inner, the medial aspect

(42:27):
of the frontal and parietal lobes, but also areas in the
temporal lobes which have long been associated with memory.
And it it could be caricatured. It's a kind of daydreaming
network, because it is particularly active when people
are recollecting the past, anticipating the future,
thinking about moral quandaries.It there is some really

(42:51):
interesting evidence that when people are engaged in creative
work, when they're actually producing, writing a song,
ending a picture or writing a novel, that a full network will
be active. But unusually, it will be active
in conjunction with the executive front apparatal

(43:13):
regions which normally are engaged when you are dealing
with an external task. So you have typically in
cognition there's a kind of Cecil relationship and also an
anti correlation between the executive network and the
default mode network. If you're resting and
daydreaming, default mode network is active.
If you've been given a task, tell me as many words as you can
think of in the next minute, beginning with the letter P,
those front bridal networks become active in the creative

(43:36):
state. There seems to be a more
harmonious relationship between the, those front bridal networks
and the and the default mode network, which I think it's
intuitively very appealing. So I think the idea that that
creativity has to do with dreaming lucidly isn't is, is an
appealing idea. They're also in a relationship

(43:57):
with the salience network. This is network of regions which
has to do with attributing valueto to activities and things in
the world. And then I think creativity has
to do with dreaming lucidly about things that matter to us.
So there's the idea that that creativity may involve a
particularly harmonious interaction between the fault

(44:18):
mode, front parietal and Saiyansnetworks.
This is a little bit fanciful, but there is some there is some
empirical evidence now that that's that's the case.
You briefly touching on this, but I think it's best for me to
ask it directly. From an evolutionary standpoint,
why do you think imagination evolved at all?

(44:38):
I mean, what advantage does detaching from the present give
us as a species? Yeah.
Well, I mean, another, another characteristic feature of human
life that distinguishes us from animals is culture.
You know, our lives are absolutely so true by imbued

(44:58):
with culture, where we are constantly using skills,
traditions, artifacts which havebeen developed over centuries,
millennia. The words we use, the, the
clothes we wear, the, the tools we're we're, we're we're we're
constantly working with. And culture ultimately depends

(45:23):
on individual acts of human creativity.
So there is a sense in which ourhuman lives, that the bedrock of
our human lives is imagination in that productive sense, the
the sense of imagination that allows us to produce things that
are both both new and, and useful.

(45:47):
And early on, I, I gave a definition of imagination which
has to do with the capacity to detach cells from here and now.
And that that detachment is really required for these acts
of creativity. We have to remove ourselves from
the from the, the immediate we we have to forget the kind of

(46:10):
immediate biological demands andlose ourselves in creative
tasks, creative work to bring about the the cultural
traditions and artefacts which which define us.
Yeah. And I think one of the things I
wrote here was that you say thatimagination is some is not

(46:30):
simply about we imagining, but rather that we share
imagination. And that's a beautiful image.
Yeah. So, so there are four big ideas
in the book, if you like, which I think we we touched on all but
the last one though. So I'll just very briefly
rehearse them. The first is that we live much

(46:52):
of our lives in our heads. We're very often detached from
the year and now there's overwhelming evidence for that.
And most people listening to this program would probably
agree that it's true from their own experience.
And that becomes a little less puzzling when you appreciate
that your moment to moment experience involves a, a
generative act, a creative act. And as we've been discussing,
when we engage in sensory imagery, we, we run those

(47:15):
perceptual systems that are involved in moment to moment
experience offline. Now, the second or third things
I've said that I think would be true of, of animals.
So I'm sure there are many animals who enjoy conscious
experience. It depends on activity in their
brains. And I think it's quite like you
that many animals can imagine inthe sense, for example, that

(47:36):
they, that they dream animals have REM sleep.
And I think there's no reason tosuppose that they don't enjoy
some conscious experience in their dreams.
The 4th big idea in the book is that what is distinctive about
us is that we have evolved to share what we imagine.
And I think you can see the lastthree million years or so of

(47:58):
human evolution since startup ofscenes first began using tools
in, in those terms, we have become extraordinarily
accomplished mind sharers with the help of language, of course.
But I think I think there are precursors to language or

(48:19):
capacities which are in a way more fundamental to language,
like, like that ability for joint attention which develops
extraordinarily early in, in thelives of human infants.
And our theory of mind, our intuitive understanding of what
is passing through one another'sminds, which which I think is
built on that joint attention that develops so early in, in

(48:42):
the in the, in the shared lives of infants in there parents.
Given the rising of AI currentlyand large language models which
generate creative outputs, but do you think machines can truly
ever imagine? Or is imagination just
inseparable from conscious or embodied experience?

(49:06):
Well, this is such a difficult question and AI is so
impressive, isn't it? That's I'm not sure any of us
quite yet had time to to work out the answer to that question.
Sorry, Adam, but there's on Grok.
If you go into Grok we and there's a section, if you just
click imagine, it just starts toproduce so much high quality,

(49:29):
very, very imaginative and creative images.
But is it really, really an imagination?
So I, I don't think that most, Idon't think that large language
models are conscious have experience.
That would be my intuition. I suspect that most people would

(49:51):
agree with that at the moment. So if you regarded consciousness
as a, as a prerequisite for whatyou're describing as real
imagination, then then no, current AI systems don't have
imagination in that sense. They clearly, they clearly have
some of the elements of imagination, though.
I mean, one, one of the processes involved in

(50:15):
imagination is the ability to produce a huge number of
variations on a theme. You know, a little as as the
genome does in through mutation.And it's probably AI would think
AIM is capable not only of generating variations, but also

(50:39):
selecting between them, which isa kind of another, another
crucial step. So, you know, it's on the way to
producing outputs that are I think it has arrived the at a
state in which you can produce outputs that are are that
somewhat resemble rival those that we produce through

(51:01):
imaginative work. But I don't think it has, I
don't think it has conscious experience of the process and I
don't think that at the moment it's quite capable of achieving
outputs like those that we valuemost highly.
But it may may well get there before law.

(51:24):
I mean, what if the things that these large language models do
is often hallucinate, confabulate, generate completely
incorrect information? And I think that would be the
best way to move on from as a neurologist, as someone in the
medical field, you're often encountering disorders, extremes
and and uses of imagination thatwould otherwise be called
pathological. At what point would you consider

(51:45):
an aphantasic or a hyperphantasic?
A striking example that's to not, not let's say atypical, but
rather disordered. I know if we had to look at it
from a medical perspective, it would be if this is affecting
their life, their quality of life or impacting relationships,
etcetera, causing harm. But from a, let's say,

(52:06):
perceptual standpoint, if you were to look at it in terms of
some someone studying it behind a lab, when do do you see it as
something completely running amok, let's say?
Yeah. I mean, as, as you imply, the
clinically the concern, the question is whether the

(52:27):
experiences are impacting somebody's life in a, in a way
that causes them serious practical disadvantage.
And I think, I think that criterion is actually quite
important because many people have experiences that might be

(52:51):
thought of as pathological, but really aren't because they are,
they're not bothering the individuals and they actually,
they actually have a potential values.
So I mean, an, an example is obvious example is voice
hearing. You know, voice hearing is
associated, of course, with psychosis in some cases and
doesn't, doesn't have a very good reputation generally.

(53:12):
But there's a fair proportion ofpeople, at least 1% of the
population who regularly hear voices which don't disturb them.
They, they, they live quite happily with them, often a
single voice, often a benign 1. And many writers, many authors
describe harnessing voice hearing in their in their

(53:34):
creative work. I think it was very bad breathe
who said that? You know, you, you lie in bed
and when the, when the voices reach a sudden pitch, you, you
get out of get out of bed and write down what they're what
they're saying. That's, that's how he, he, he
created. So I think it's difficult to to

(53:55):
draw a kind of principled line of the kind you were requesting.
And, you know, dynamic, autonomous, generative brains
are producing all kinds of what experiences.
I think I made it many of which can.
Be useful to us. I think I made it difficult by

(54:16):
answering the question while asking it as well.
I mean, it is very difficult to tell when imagination ends and
psychosis begins because it is such a creative sort of
experience. And and a lot of times I've
encountered patients, acutely psychotic schizophrenic patients
who still don't necessarily showsigns of harm to themselves,

(54:37):
others or in any way to the reputation.
And you have to then consider, OK, is this technically an issue
right now? And sometimes it's just not.
Yeah, I I guess creative work, particularly creative fiction,
is interesting to think about inthis context, isn't it?
Because novels don't survive. We don't people don't continue

(55:02):
to read them unless they kind ofwork.
There's a readers provide quite a harsh test for the output of
novelists. So the fact that people continue
to read James Joyce or Virginia Woolf, I think implies that

(55:24):
although somebody reading from the first time might have
thought this is this is crazy stuff.
It actually, it kind of turns keys in, in the locks of
perception successfully. So some things of course, won't.
I mean, I, I remember going to apoetry I, I got a talk at A, at

(55:44):
a poetry festival a few years back and I listened to one
particular reading late in the evening and I thought, you know,
this, this is really just thought disorder.
This, this isn't poetry. And I may have been wrong, but
you know. And, and you may have been right

(56:05):
to be honest, but I may have. Been I may have been right, I
may have been right. And I think, I think the the
kind of audience then or the read, the readership then
provides the the the test. Yeah, in your work, Adam, in in
your work with let's say epilepsy or memory, have you
seen how imagination sort of influences one sense of self or

(56:25):
continuity of memory? So tell me if I'm answering the
wrong question here. But certainly what this, what
your question recently reminds me of is the experience of

(56:46):
people with affantasia as opposed to hypantasia.
So some people at Fantasia have a very, very thin
autobiographical memory verging on what's been described
recently as the syndrome of severely deficient
autobiographical memory, again, the creation of Brian Levine's
group. So these are people who who say
that reading about when they read their own Diaries, it's

(57:08):
pretty much like reading about somebody else's life.
They really can't, they can't reenter their past experiences.
They can't relive them. And that can be a bit
problematic for them. They it can, it can leave you,
leave you with a rather insecuresense of your own identity.
And I I studied a couple of American participants who were

(57:33):
both in the situation actually with that with memory loss
related to epilepsy rather than a Fantasia straightforwardly,
But they said that when they told stories about their past,
they they often felt rather insecure.
They kind of wondered whether whether this was just made-up
because because they couldn't reinhabit these these past
experiences. So I think that the ability to,

(57:59):
to, to relive experiences contributes to a sense of
personal identity and continuityover time and, and helps to, to
give our, yeah, give our memories kind of authenticity
that, that otherwise they can like, I'm not sure whether
that's quite what you're asking.No, I guess the reason why I
brought that up would was because when you look at

(58:20):
disorders like epilepsy or or any sort of neurological
disorder, the question then arises, can imagination be
trained, rehabilitated or or perhaps therapeutically
employed? So what are your thoughts on
this On recovery? Cognitive flexibility?
Yeah. So I think thinking specifically

(58:42):
of people with aphantasia, it seems to be difficult to
cultivate sensory imagination. So many people that Fantasia
say, you know, can I learn, can I learn to visualise?
Quite a lot of people that have Fantasia anecdotally have told
me that they've tried, they've used screening techniques where
you look, look at an object, tryto hold it in your mind's eye,
try to do this for longer periods.
It does seem hard, but I hope itdoesn't easier to to to build

(59:04):
sensory imagination. So my guess is that there's some
biological obstacle there. Look.
Have have you seen Gadem? Have you seen cases where people
have learnt to to change this experience?
I know a lot of your data does show that genetically there is a
factor, so you're more likely tohave it if you someone in your
family does have it. But have you seen any success
stories? Not that.

(59:26):
Not terribly. Not that I have detailed
accounts. I've known quite a lot of people
have said that medication has occasionally given them access
to imagery, which is is really very interesting.
The best person I have is psychedelic type of medication.
What would it be? Is it?
Some, well, sort of psychotropic, sometimes

(59:47):
psychedelic, sometimes other drugs working on the on the CNS,
some something I would love. I hope to study further, but I
haven't seen, I haven't seen really detailed convincing
accounts from people who've beenable to train themselves to to
deal with this. Adam, aren't you?
You're an Exeter, right? So.
I mean, Adam wrote these days. Shusters Hughes is right there.
So psychedelics he yeah, he's right there.

(01:00:10):
So yeah, you can probably help study this.
Yeah, yeah, yeah. But for people who have imagery,
then it it can be used therapeutically for sure.
Dimitri is of course, used a good deal in mental practice by
athletes, by musicians. It can be harnessed in forms of

(01:00:36):
psychotherapy. So yeah, it it, it has.
Did did we touch on dreams and daydreams?
Because I know part of your worktalks about how it's, it seems
to be distinct and I know at some point you mentioned the
fact that people who dream are able to produce these mental
images. Do we have a reason why
neurologically, Is it just because of specific parts of the

(01:00:58):
brain or would you like to explore that a bit deeper?
Yeah, sure. So there's this very, very
intriguing dissociation. Most, it's not from everyone,
but most people who have Fantasia, most people who lack
the ability to call imagery to mind deliberately nevertheless
dream visually. So they experience visual images
in their dreams. And this can seem very puzzling.

(01:01:19):
I think it becomes less puzzlingwhen you know that or when you
learn that the brain is in a really very different state in
wakefulness and dreaming, sleep,rapid eye movement, sleep.
So it's in a different state in a neurochemical sense.
So when we're when we're awake and alert, there's a whole

(01:01:39):
number of whole range of neurotransmitter systems based
in the brain which are working full tilt to maintain
gratefulness and alertness. And in dream sleep, most of
those systems are quiescent. You have a good deal of acetone,
choline around cholinergic drive, but noradrenaline,
serotonin, dopamine systems are all relatively quiescent.
So the brain is in a different neurochemical state in dream

(01:02:02):
sleep to to the state of wakefulness and it's also in a
different state of regional brain activation.
So when we dream, we switch off front variotal regions that are
involved in cognitive control and we activate regions deeper
in the brain, in the brainstem and in the limbic system.
So one way of of caricaturing orcharacterizing the difference
would be that wakeful imagery istop down.

(01:02:24):
I ask you to imagine an apple, you make a kind of conscious
decision to to do so and you canthen drive sensory systems from
the top down. Whereas dreaming is a much more
spontaneous bottom up kind of kind of process.
So there is good evidence that when we experience visual
imagery both in wake from the sun, in dreams, we activate

(01:02:44):
visual cortices. But I think the way you arrive
at that activation is is very different in those two states.
And I think it there's somethingelse we should mention and and
perhaps touching in more detail would be the fact that certain
parts of the brain are in are more affected in aphantasia than
others. So the typical case would be
your patient MX, the one that instead of introduced to all of

(01:03:07):
this exactly which part of his brain had the stroke and and
have you noticed since that certain other regions, perhaps
not the same one, have contributed to authentic states?
Yeah. OK.
So MX is a the patient who interested, got me interested in
this topic about 20 years ago, alittle over 20 years ago.
So this was a patient who's referred to me by his General

(01:03:29):
practitioner with a letter saying this man's lost the
ability to to imagine. And it turned out that
specifically he'd lost the ability to visualize.
He was a very articulate. He's a very articulate man who
previously used to get himself to sleep by visualising the
faces of friends and family could no longer do so.
He said that when he read a novel, he would enter a visual
world. Previously, this was no longer

(01:03:49):
the case. His dreams actually became a
visual initially. So he would have dreams, but
they had a narrative content rather than a a visual content.
So we were very intrigued by this really compelling account
he gave of a change of the experience and in the end did a
brain imaging study, functional brain imaging study to see what

(01:04:10):
what the difference was when he tried to visualize from the
brain activity of people with imagery.
And it turned out that when he looked at famous faces, he had
normal brain activation just like the control participants
who were he was a surveyor. Control participants were
matched for for occupation. But when he tried to visualize,
he hypo activated regions in thevisual brain in the occipital

(01:04:35):
and temporal lobes, areas that most of us activate when we
visualize, producing that faint echo of of perception that we
experience when we visualize. He could no longer activate
those areas. So that seemed to be a nice
neural correlate for the change he described in his experience.
I was affecting or I hypothesized that we might see

(01:04:57):
something similar in people thatwith lifelong hyphantasia, who
we then went on to study quite awhile later.
But it turns out that the story is probably a bit a little bit
more complicated. There is a difference between
brain activity and people with lifelong hyphantasia and people
with imagery, but it's not quiteas simple and it it looks as if

(01:05:19):
it may. There's one particular area that
may well indeed play a key role in this.
This has been prisoned recently,the fusiform imagery node.
So this is an area in the other surface of the temporal lobe
which seems to play a particularly important role in
visualization. It's activity covarius to some

(01:05:39):
extent with the vividness of ourimagery experience.
It's functions not yet fully understood, but it does seem
that variations in the activity of this region may play a a key
role in lifelong adventasia, thewhich is much the commonest form
that accounts for the the great majority of the 4% I mentioned

(01:06:01):
earlier. Adam, where would you like to
see the future of Adventasia research going?
What are the next steps? Are you guys working on anything
specific or do you know any labsdoing something similar?
Where is this headed? Yeah, I mean there's there are,
there are still a huge number ofquestions to answer.
One question is what are the subtypes of apantasia?

(01:06:22):
So I don't think it's a single thing.
I think it's a variation in experience which can occur in a
number of different contexts. So for example, it may be that
there's a subgroup of people with face recognition
difficulties, possumagnosia, or interestingly interesting that
the fusiform place area is quiteclose to the musical mimetry.
Note subgroup of people with particularly severe memory
difficulties, A subgroup with autism.

(01:06:43):
So we need to try to tease out the the various subtypes.
Not surprising that there shouldbe a number of different types
because if you have a complex network of the kind that's
responsible for visualization, you might predict that it could
be perturbed in more than one way.
You mentioned genetics. Oh yeah.
If you are a fantasic, there's aroughly tenfold increase in the

(01:07:07):
likelihood that your first degree relatives will be hinting
at some genes involved in the modulation of imagery.
Vividness wouldn't be surprising.
Genes influencing all the psychological questions, so far
as I know. That's something else.
We're keen to look at more to learn about the the neural

(01:07:28):
basis. There's an interesting question
which is much discussed at the moment about whether people who
have Fantasia have unconscious imagery in in some sense.
I think that has to be true in avery broad sense because people
who have Fantasia are able to recognise things just fine as a
rule, so they know what things look like.
They, they must have stored knowledge of appearances in

(01:07:50):
their brains, which you would have thought is just what you
need to generate imagery. But they can't take that extra
step, even though they can recognize they can't use that
knowledge to generate conscious images.
So in a very general sense, I think there must be unconscious
imagery in in the brains of folkwith an aphantasia.
But whether that's a good description out of finer grain

(01:08:13):
is, is being debated at the moment.
The the nature of unisensory andmultisensory aphantasia is
interesting. So I've said that most people
that Fantasia have diminished imagery in all sense modalities,
but it's not true. But all there are some people
who seem to have very focal visual auditory aphantasia, for
instance. So there's there's more to learn

(01:08:34):
about that more to learn about the mental health associations
of aphantasia and aphantasia. So I've mentioned that
aphantasia is is linked with autism.
It might protect you from PTSD, for example, like avantasia
might perhaps predispose you to psychosis.

(01:08:54):
So really quite a a fair number of of questions for us to keep.
It's it's so it even makes me think about certain other
neurologists and their work. If you take someone who's worked
like Michael Gazzaniga, some of the corpus carsectomy, all the
implications of the parts of thebrain that now see and speak
versus the other. And how would you study those
people who are fantasic if you think of VS Ramachandans phantom

(01:09:18):
limbs? I mean do how are they going to
experience these phenomenon? It's quite an intriguing set of
features because you could studythis with everything.
Yeah. And it's, it's like the Sky's
the limit type of thing with advantage or hyper fantasic
patients. Is there anything in particular
you're looking forward to withinthis research?

(01:09:39):
So I'm really interested in all the topics I've mentioned.
What I'm, I'm, I'm hoping to write another book focusing on
this because the, the book that we've been talking about the
shape of things unseen ranges very widely over the
imagination. And I don't, I don't really feel
I've done justice to our Fantasia, hyper Fantasia yet.
And what I'm particularly looking forward to is actually
talking to people more because I've so much enjoyed my, my

(01:10:01):
conversations with people who enjoy these one of the
intriguing different kinds of experience.
I just, I want to, to get a, a, a closer feel for the, for the
texture of, of their experience.So so conversations on my
research focus for the for the next year or so.

(01:10:22):
When you look at this, let's move into sort of the concluding
features where it comes to philosophy, meaning future of
imaginative science. If if imagination constructs not
just what we perceive, but what we value and mean, what do you
think this tells us about the nature of existence itself?

(01:10:44):
I think it tells us that the universe is much odder than it
seems. You know, we, there's a huge
amount of mystery and I'm not a religious person, but I but I'm
certainly prepared to accept that there's a huge amount we,
we don't understand, probably never will understand that the
universe is a, is a very, it's very fascinating, but also

(01:11:06):
deeply, deeply mysterious place.I think, yes, there's an Auden
poem where he somewhere says that the, the world is much
other than it seems, and I very much subscribe to that view.
I have a recurring feeling sort of moving from the universe to
to to the human, that this general line of work should be

(01:11:30):
helpful in improving human relations.
We talked about the fact that wehave a huge capacity for for
difference, storing difference in our brains.
And I think this this helps to explain the conflicting and

(01:11:57):
sometimes incompatible cultural traditions which we live within.
I think understanding that our brains have this huge story
space for difference and that culture is fundamental to our
lives, but that which culture wehappen to operate in is very
much a matter of chance, highly contingent.

(01:12:19):
That kind of cluster of facts should both make us respectful
of other traditions and also andof course respectful of our own,
but also willing to accept that no tradition has a, is

(01:12:40):
privileged, has a has a claim tosupremacy.
I think it's, I think there's a kind of strong argument for
tolerance from science in in this, in this line of thought.
And tolerance is something we badly need, seems to me.
No, I agree with you. I think at this time of life,

(01:13:02):
it's clear that that is the one thing we we definitely do need.
Before we close off. Adam, I want to do.
There's something I have to ask you.
I mean, I ask everyone this question.
Do you ever think about the mindbody problem as a neurologist,
someone deeply ingrained with tinkering with the human brain
and mind, at what point do you see the separation?
Is there a separation? Is there a mind body problem and

(01:13:24):
do we have free? So it's really what brought me,
drew me into neurology. So I did a philosophy and
psychology degree and it was sort of the mind body problem
that made that, that motivated my decision to become a
neurologist. So actually, I remember just
sitting in, in cafes with a, with friends, I guess aged about
20, just unable to understand why everybody wasn't talking

(01:13:46):
about the mind, brain, mind bodyproblem.
You know, I thought this was such an extraordinary problem
that it, it should be really absolutely in the, in the
foreground. And I, I read a book about
consciousness my, my first book because I was so fascinated by
the topic and I remain fascinated by it.

(01:14:07):
But I guess I've come to the conclusion that as it's
currently posed, the mind, body,mind, brain problem is
insoluble. And I suspect it's insoluble
because the concepts that we areoperating with aren't up to the
task at the moment. I think we probably need to
adjust our understanding of bothmind and matter in in some

(01:14:30):
fairly important ways to, to bring them into line with one
another. But I think that has to be
doable in a sense, because they they clearly, they clearly are
so deeply interconnected that that that there must be sense to
make here. I'm just not sure that I think
the hard problem of consciousness is, as it's

(01:14:53):
typically stated in insoluble. So I've slight, I've somewhat
said it to one side and I, I guess I came to the conclusion
that while consciousness was absolutely fascinating, it's
consciousness per SE is not whatdistinguishes us from other
creatures. And I, I became rather
fascinated by the idea that imagination, as we've been

(01:15:14):
discussing, is the capacity thatthat, that that draws the line
and. And with these imaginative
states, when it comes to certainpeople's word, Benjamin Libbit
others, do you think that peoplehave free will?
So because I find that when someone has a certain definition
of consciousness, then they're left trying to spray in free

(01:15:35):
will. And whether they have one or
not, sometimes it depends on their view of consciousness.
I think all we're compatible is I think that most of all of what
we want free will to do for us is compatible with what we
understand about neuroscience. So yes, we we, we have free
will, but our actions are in a certain, not the sense,
determined. Well, I think, Adam, the final

(01:15:58):
question I have is, do we in some sense imagine the world
into being? Absolutely.
You want to just elaborate on that before we close up?
I think that our apprehension ofourselves and of the world, our

(01:16:21):
mental lives, are the product ofour dynamic, energy consuming,
generative, imaginative brains. Yes, we we imagine ourselves in
the world into being. I think it's absolutely
beautiful. Adam if if someone tuned into
this episode, unfortunately right in this moment, at the
very end, what would be the one thing you'd want them to know

(01:16:43):
about the human brain and mind? Let me, let me just read you the
quotation at the very end of thebook which I came across on a
wall. It was graffiti on a on a wall
in Bloomsbury. I wish I could show you when you

(01:17:07):
are lonely or in distress, the shining light of your own being.