0:00:02 > 0:00:05Imagine if you picked up the paper one morning but you couldn't read it.
0:00:05 > 0:00:08The letters looked foreign, unrecognisable.
0:00:08 > 0:00:12But you realised you could still write.
0:00:12 > 0:00:14So, you can write but you can't read.
0:00:16 > 0:00:17Imagine what it would be like
0:00:17 > 0:00:20if you'd never been able to recognise anyone.
0:00:20 > 0:00:22Not even your closest family and friends.
0:00:22 > 0:00:25No matter how many times you'd seen them,
0:00:25 > 0:00:27you still couldn't recognise their face.
0:00:28 > 0:00:32And what if you couldn't see and you couldn't hear?
0:00:32 > 0:00:37But you had to find a way to make sense of the world.
0:00:37 > 0:00:41So your only way to communicate was through touch.
0:00:44 > 0:00:48Wow, look at that! Look at that!
0:00:48 > 0:00:51Or what if you'd only ever seen the world in 2-D,
0:00:51 > 0:00:55and then, in your fifties, you developed 3-D stereo vision?
0:00:57 > 0:00:59Imagine how you would react
0:00:59 > 0:01:03if the world started popping out at you for the first time.
0:01:06 > 0:01:09These are the questions neurologist and writer Oliver Sacks
0:01:09 > 0:01:13has been trying to come to terms with for 50 years.
0:01:43 > 0:01:48I wish I could do what Spock sometimes does in Star Trek,
0:01:48 > 0:01:55when he puts his hand, I think, on the head and by a Vulcan trick,
0:01:55 > 0:01:58is able to fuse minds and know what's going on.
0:01:59 > 0:02:00What's going on?
0:02:04 > 0:02:09Dr Oliver Sacks is the most famous neurologist in the world.
0:02:11 > 0:02:15With his gift for storytelling, he's managed to cross over
0:02:15 > 0:02:17from medical science into popular culture,
0:02:17 > 0:02:22with bestsellers like The Man Who Mistook His Wife For A Hat, and Awakenings.
0:02:23 > 0:02:27Three years ago, I made a documentary with Sacks.
0:02:27 > 0:02:31We discussed how music can be used to overcome neurological conditions.
0:02:33 > 0:02:36I met several of his case studies, including Matt,
0:02:36 > 0:02:41whose love of drumming helped him control his extreme Tourette's.
0:02:41 > 0:02:43CLEARS THROAT
0:02:43 > 0:02:45DRUM ROLL
0:02:52 > 0:02:55It's Sacks' humanity and his curiosity which have driven
0:02:55 > 0:02:59and inspired him for over half a century.
0:02:59 > 0:03:02Follow my finger with your eyes.
0:03:02 > 0:03:06And he's often drawn on his own experience, his own ailments,
0:03:06 > 0:03:10in order to understand the challenges facing others.
0:03:13 > 0:03:17But it's only now, after discovering a cancerous tumour in his eye,
0:03:17 > 0:03:20that he has finally chosen to explore the wonders
0:03:20 > 0:03:23of sight and perception
0:03:23 > 0:03:26and the catastrophes that ensue when things go wrong.
0:03:28 > 0:03:32In his new book, The Mind's Eye, Sacks goes back to his own childhood,
0:03:32 > 0:03:36and finally owns up to a lifelong inability
0:03:36 > 0:03:38to recognise or remember faces.
0:03:41 > 0:03:44It's been about three years since I've seen Sacks.
0:03:44 > 0:03:47Having read about his severe face blindness,
0:03:47 > 0:03:51I was wondering if there's any way that he'd recognise me.
0:03:51 > 0:03:54When I came in right now, I was laying bets
0:03:54 > 0:03:57as to whether you would recognise me or not.
0:03:57 > 0:04:00How did you know it was me as I came in?
0:04:00 > 0:04:01Erm...
0:04:01 > 0:04:03Well, I didn't.
0:04:03 > 0:04:08I experimentally said, "Nice to see you again,"
0:04:08 > 0:04:13to the...to a plausible person, which happened to be you.
0:04:13 > 0:04:16So, Oliver, I'm going to give you a little test here.
0:04:16 > 0:04:20- I was afraid of that. - All right, here's the first.
0:04:22 > 0:04:25Do you recognise that person?
0:04:25 > 0:04:26Erm...
0:04:29 > 0:04:34I know I should, because otherwise you wouldn't be showing it to me.
0:04:34 > 0:04:38Erm... Er...
0:04:38 > 0:04:44She is young, she is black, she is famous, so I would infer,
0:04:44 > 0:04:49I would think there's a good chance of it being Obama's wife.
0:04:49 > 0:04:52OK, that's the first bit. Now here's the next one.
0:04:58 > 0:05:03I don't know, no idea.
0:05:03 > 0:05:05OK. Do you know who that is?
0:05:08 > 0:05:12He's from a slightly unusual angle,
0:05:12 > 0:05:15but I would think that that's the husband.
0:05:15 > 0:05:20- That's a good way of putting it, the husband of whom?- Of Obama's wife.
0:05:20 > 0:05:23That's the husband of Obama's wife? Well, you done well there, that's true.
0:05:23 > 0:05:28- That's one you've got right. - I'm sorry, not two right?
0:05:28 > 0:05:32No, you didn't get the first one right. Now what about this one?
0:05:35 > 0:05:37Well, she's grey-haired,
0:05:37 > 0:05:43she has an imperious look, I would guess, the Queen.
0:05:43 > 0:05:46So you've done not badly.
0:05:46 > 0:05:50- It was Elvis Presley who you hadn't recognised.- I see.
0:05:50 > 0:05:52And did you show me both Obama and Mrs Obama?
0:05:52 > 0:06:00- No, I showed you Oprah Winfrey.- Oh, yeah.- You got Obama and the Queen.
0:06:00 > 0:06:01OK.
0:06:02 > 0:06:05Is it a strain not being able to recognise people?
0:06:05 > 0:06:09Well, sometimes it's a relief! No.
0:06:09 > 0:06:13People can be greatly offended and I think one needs to
0:06:13 > 0:06:18out oneself in this respect to sort of diffuse situations.
0:06:18 > 0:06:22And since I wrote on the subject, I've had lots and lots of letters
0:06:22 > 0:06:25from people who have said they had something similar,
0:06:25 > 0:06:30it had been lifelong and other people in the family had it, and I got the sense
0:06:30 > 0:06:34that here was something not uncommon out there in the general population.
0:06:37 > 0:06:41Face recognition is crucially important for humans,
0:06:41 > 0:06:46most of us are able to identify thousands of faces
0:06:46 > 0:06:49or easily pick out a familiar face in a crowd.
0:06:49 > 0:06:53But severe face blindness is estimated to affect
0:06:53 > 0:06:56at least six million people in the US alone.
0:06:56 > 0:07:00There's a particular part of the brain,
0:07:00 > 0:07:03towards the back of the right hemisphere,
0:07:03 > 0:07:07which seems to be especially concerned with the recognition of faces.
0:07:07 > 0:07:12There's argument as to how much this particular area
0:07:12 > 0:07:15is a product of evolution and present at birth
0:07:15 > 0:07:22and dedicated to the recognition of faces and how much it develops
0:07:22 > 0:07:27through training and culture, because, of course, we're a social animal
0:07:27 > 0:07:30and facial recognition is very essential for us.
0:07:32 > 0:07:33At two-and-a-half months,
0:07:33 > 0:07:38babies respond to smiling faces by smiling back.
0:07:38 > 0:07:44This engages the mother to smile more, to talk, to hold the child.
0:07:44 > 0:07:48In other words, to initiate the process of socialisation.
0:07:48 > 0:07:52We interact in the world with the people we know and love
0:07:52 > 0:07:55through the recognition of their faces.
0:07:55 > 0:07:59So people with face blindness have to learn to be resourceful.
0:07:59 > 0:08:07They find strategies, such as recognising people by an unusual feature, spectacles, facial hair,
0:08:07 > 0:08:09a certain sort of clothing.
0:08:09 > 0:08:12Then there's voice, posture or gait.
0:08:12 > 0:08:16And, of course, context and expectation.
0:08:17 > 0:08:22And Oliver's problem is not just confined to recognising other people's faces.
0:08:23 > 0:08:26I often start apologising to a, er...
0:08:26 > 0:08:29a large, clumsy, bearded man,
0:08:29 > 0:08:33and then realise that it is a mirror.
0:08:33 > 0:08:37Once, when I was at a table outside a cafe,
0:08:37 > 0:08:43and I turned to the window next to me
0:08:43 > 0:08:49and I started checking myself, checking my reflection,
0:08:49 > 0:08:54but then I realised the reflection was not doing what I was doing,
0:08:54 > 0:08:58but that on the other side, there was a puzzled man with a beard
0:08:58 > 0:09:03who wondered why I was feeling myself in front of him.
0:09:03 > 0:09:09So I can take others for myself as well as myself for others.
0:09:11 > 0:09:13'But is there any circumstance, I wondered,
0:09:13 > 0:09:17'where a deficit like this can be turned into an advantage?
0:09:17 > 0:09:23'The New York-based painter Chuck Close is one of the world's most successful artists.
0:09:23 > 0:09:26'His work sells for millions of dollars,
0:09:26 > 0:09:30'but, like Sacks, Chuck Close has been face blind since childhood.
0:09:30 > 0:09:34'Chuck also suffered a spinal artery collapse in his forties,
0:09:34 > 0:09:37'and he's relied on a wheelchair ever since.
0:09:37 > 0:09:41'But he continues to paint with a brush strapped onto his wrist.
0:09:41 > 0:09:44'I've known Chuck for years.
0:09:44 > 0:09:47'I spent time with him at his studio in New York,
0:09:47 > 0:09:49'where I've watched him work.
0:09:49 > 0:09:51'But I had no idea he was face blind.
0:09:51 > 0:09:55'He never mentioned it, and I never noticed anything unusual.
0:09:55 > 0:10:00'I only found out when I read about him in the footnotes of Sacks' latest book.
0:10:02 > 0:10:04'It had been a while since I've seen him,
0:10:04 > 0:10:07'so I wondered if Chuck would recognise me.'
0:10:07 > 0:10:09DOORBELL BUZZES
0:10:12 > 0:10:15- Hello, Alan.- Chuck!
0:10:17 > 0:10:19- How are you?- I'm good.
0:10:19 > 0:10:21How have you been?
0:10:23 > 0:10:27- It's so good to see you.- Great to see you. How are things?- It's good.
0:10:27 > 0:10:30- You're looking good. I like that look.- Getting a little more hair.
0:10:30 > 0:10:32- So tell me, honestly...- Yeah?
0:10:32 > 0:10:35Did you immediately recognise me, or did you just know...?
0:10:35 > 0:10:37I knew you were here.
0:10:37 > 0:10:39- That's not the same thing! - No, it's not.
0:10:39 > 0:10:44- When we first met a few years ago, and I spent days with you... - Days, yeah.
0:10:44 > 0:10:46I thought you'd never leave.
0:10:46 > 0:10:48But you never told me.
0:10:48 > 0:10:51Most people in my whole life never noticed
0:10:51 > 0:10:55that I wasn't remembering their names or recognising them,
0:10:55 > 0:10:58even though it was a tremendous struggle.
0:10:58 > 0:11:03It came to some of my best friends as a total surprise.
0:11:03 > 0:11:04But it is a nightmare.
0:11:04 > 0:11:07It's one of the reasons why my stomach is tied in knots,
0:11:07 > 0:11:09and why I'm a nervous wreck.
0:11:09 > 0:11:13It takes a tremendous amount of energy.
0:11:13 > 0:11:15When did you first realise?
0:11:15 > 0:11:18When I go back to your childhood and think about that moment
0:11:18 > 0:11:20when you had learning problems,
0:11:20 > 0:11:23you found it difficult to absorb information.
0:11:24 > 0:11:26As long as I can remember.
0:11:26 > 0:11:29I remember being in kindergarten or first grade,
0:11:29 > 0:11:34and I still, by the end of the year, didn't know who my classmates were,
0:11:34 > 0:11:36and I also didn't know their names,
0:11:36 > 0:11:40so between not recognising who they were or what their names were,
0:11:40 > 0:11:43I was in big trouble.
0:11:43 > 0:11:46- Did you realise that was unusual? - Oh, yes.
0:11:46 > 0:11:48'Yes.
0:11:48 > 0:11:52'My mother was especially concerned, as you might imagine,
0:11:52 > 0:11:55'and I went to see a lot of doctors.
0:11:55 > 0:11:58'They had no explanation for it.'
0:11:58 > 0:12:01Even learning disabilities didn't exist in the '40s.
0:12:03 > 0:12:04'Overlooked at school,
0:12:04 > 0:12:08'Chuck developed an early love for theatrical and creative arts.
0:12:08 > 0:12:13'He eventually gained a place at Yale's art school,
0:12:13 > 0:12:17'and emerged on the New York art scene in the 1960s.
0:12:17 > 0:12:22'This was the time of abstract expressionism and pop art,
0:12:22 > 0:12:25'but Chuck Close went against the grain.
0:12:27 > 0:12:33'He painted huge realist portraits for which he's become famous.'
0:12:33 > 0:12:36There is a wonderful irony or compensation
0:12:36 > 0:12:41that someone who is so blind to faces is such a master at portraying them.
0:12:46 > 0:12:51I wouldn't be a portrait painter had I not had face blindness, I'm sure.
0:12:51 > 0:12:57'Every aspect of my work was determined by my disabilities and deficits.
0:12:57 > 0:13:00'And that's driven everything that I do.'
0:13:00 > 0:13:04Now, if you move your head half an inch, it's a whole new head.
0:13:04 > 0:13:08- Perspective and angle changes, you see something completely different?- Yeah.
0:13:08 > 0:13:10It's like watching some organic process.
0:13:10 > 0:13:13It's like looking at a...
0:13:13 > 0:13:16at a bag full of cats or something.
0:13:16 > 0:13:20It's going to poke out here, poke out there. Here, there, whatever.
0:13:20 > 0:13:24It's going to constantly be changing its shape.
0:13:24 > 0:13:30Most people, I think, see the continuum, see how it stays the same.
0:13:30 > 0:13:36I think I see how it's changing, and how it's changing
0:13:36 > 0:13:42somehow gets into my head and makes me think I'm seeing a new image.
0:13:44 > 0:13:49'Whilst the rest of the '60s New York art scene was creating a collective movement,
0:13:49 > 0:13:54'Chuck was a loner, making his art and dealing with his condition.
0:13:55 > 0:13:59'But his work has evolved since those early realist portraits,
0:13:59 > 0:14:02'though the basic technique remains the same.'
0:14:03 > 0:14:07'He approaches the human face through a grid,
0:14:07 > 0:14:11'breaking the face down into small square sections,
0:14:11 > 0:14:14'and, most importantly, working from a flat image.
0:14:14 > 0:14:17'Ironically, he's turned to abstraction
0:14:17 > 0:14:20'in order to make sense of the whole,
0:14:20 > 0:14:24'only gradually building up an image of the face.'
0:14:25 > 0:14:27'I'm overwhelmed by the whole.
0:14:27 > 0:14:31'I don't even know how you'd approach it as a whole,'
0:14:31 > 0:14:34so I break it down into small, bite-sized decisions.
0:14:35 > 0:14:39'The person is revealed only when you step back.'
0:14:40 > 0:14:44'It is then that the face becomes recognisable.'
0:14:45 > 0:14:49'These images are more than art works to Chuck.
0:14:49 > 0:14:53'He only paints portraits of family and friends.
0:14:53 > 0:14:56'This is how he remembers them.'
0:14:58 > 0:15:00'Chuck Close has spent his entire career
0:15:00 > 0:15:05'using his art to help him deal with his inability to recognise faces.'
0:15:08 > 0:15:10'Vision is so complicated,
0:15:10 > 0:15:14'it takes half of the brain to process what we see.
0:15:14 > 0:15:17'Light, motion, shape, memory,
0:15:17 > 0:15:21'context, are some of the things we take for granted.'
0:15:23 > 0:15:25Vision is not seamless,
0:15:25 > 0:15:29that although one might imagine one is given the visual world
0:15:29 > 0:15:32with colour and depth and movement
0:15:32 > 0:15:35and boundaries and contours and meanings all there,
0:15:35 > 0:15:40in fact there must be many, many discrete elements,
0:15:40 > 0:15:43any one of which can be knocked out.
0:15:44 > 0:15:47'The consequence of just one thing going wrong
0:15:47 > 0:15:52'demonstrates how many different elements are involved in the way we see.
0:15:52 > 0:15:56'Take reading, which we take for granted,
0:15:56 > 0:15:58'and we assume is connected with writing.
0:15:58 > 0:16:04'But reading is, in fact, based on our in-built potential for shape recognition,
0:16:04 > 0:16:06'and a separate process to writing.'
0:16:07 > 0:16:09As Victor Hugo, the French poet, put it,
0:16:09 > 0:16:12"Have you noticed how picturesque the letter Y is,
0:16:12 > 0:16:16"and how innumerable its meanings are?
0:16:16 > 0:16:20"The tree is a Y, the junction of two roads form a Y.
0:16:20 > 0:16:24"Two converging rivers, the glass with its stem,
0:16:24 > 0:16:29"the lily on its stalk, and the beggar lifting his arms are a Y."
0:16:32 > 0:16:36'In January 2002, Sacks received a letter
0:16:36 > 0:16:39'from the Canadian crime writer Howard Engel.'
0:16:42 > 0:16:44At last!
0:16:44 > 0:16:48Nice to meet you. I can see you like books, Howard!
0:16:48 > 0:16:49Well, is there anything else?
0:16:49 > 0:16:51- Come on in.- Thank you.
0:16:52 > 0:16:57'Engel was not just a bestselling author, but an avid reader, too.
0:16:57 > 0:17:01'His house is full of books. Every surface is covered in books.
0:17:01 > 0:17:03'They're his treasures.
0:17:03 > 0:17:08'But this all changed one morning in 2001,
0:17:08 > 0:17:10'when Howard woke up and realised
0:17:10 > 0:17:14'his world didn't look the same as it always did,
0:17:14 > 0:17:17'and his library of treasures had become useless to him.'
0:17:22 > 0:17:24'It was a day like any other day.
0:17:24 > 0:17:28'I got out of bed, came downstairs,
0:17:28 > 0:17:31'and went outside to bring in the morning paper.'
0:17:35 > 0:17:38'Took a look at the morning paper,
0:17:38 > 0:17:42'and suddenly it seemed to be written in Serbo-Croatian
0:17:42 > 0:17:46'or Cyrillic, or some kind of alphabet that I didn't recognise.'
0:17:48 > 0:17:51And immediately I thought, "Somebody's having me on,
0:17:51 > 0:17:53"there's a joke here,"
0:17:53 > 0:17:57so I looked at an inside page to see how far they had carried the joke.
0:17:58 > 0:18:02'They had been miraculously changed, as well.'
0:18:02 > 0:18:08Then I started getting worried and I started looking at other things.
0:18:08 > 0:18:15Everything that involved print had been changed into something unrecognisable.
0:18:15 > 0:18:19And at the same time, that's what shocked me,
0:18:19 > 0:18:24was that everything else looked exactly the way it normally looked.
0:18:24 > 0:18:27The view out the window, the things in the kitchen,
0:18:27 > 0:18:30everything looked as I expected it to look, except for print.
0:18:33 > 0:18:36As soon as I decided that it wasn't a prank
0:18:36 > 0:18:41and somebody wasn't joking with me, I knew that I'd had a stroke
0:18:41 > 0:18:44and that I'd better get myself to the hospital.
0:18:46 > 0:18:50Howard was told that his stroke had affected the visual parts
0:18:50 > 0:18:52of his brain on the left side.
0:18:52 > 0:18:54He spent the next week in the neurology department
0:18:54 > 0:18:57at Toronto's Mount Sinai Hospital.
0:18:59 > 0:19:00During this week,
0:19:00 > 0:19:03Howard's memory suffered other disorientating symptoms.
0:19:03 > 0:19:07It was a nurse that informed him that even though he'd lost
0:19:07 > 0:19:12the ability to read, he could in fact still write.
0:19:12 > 0:19:15I tested it, of course, because I didn't believe it to begin with.
0:19:15 > 0:19:19Then I found that if I wrote something down,
0:19:19 > 0:19:21I could read it immediately.
0:19:21 > 0:19:24If I looked at it five, ten minutes later,
0:19:24 > 0:19:26I'd have to sound it out word by word.
0:19:28 > 0:19:32When you discovered that you could write, but you couldn't read,
0:19:32 > 0:19:35you said, "It was like being told that the right leg
0:19:35 > 0:19:38"had to be amputated, but I could keep the shoe and the sock."
0:19:38 > 0:19:40Which I thought was...
0:19:40 > 0:19:42So, you were bereft, really.
0:19:42 > 0:19:45It was as though my library had been cleaned out
0:19:45 > 0:19:49and suddenly there was all that empty space.
0:19:49 > 0:19:54Being robbed of Dickens and Hemingway at the same moment,
0:19:54 > 0:19:58it was difficult to fathom, to say the least of it.
0:19:59 > 0:20:02He found himself unable to read and yet he can write,
0:20:02 > 0:20:04explain that to me.
0:20:04 > 0:20:11Much more of the brain is involved in writing than in reading.
0:20:11 > 0:20:15There's a particular area which becomes specialised for visual reading.
0:20:15 > 0:20:18They call it the Visual Word Form Area.
0:20:18 > 0:20:25But you do not need to visualise letters to write.
0:20:25 > 0:20:28One can write perfectly well with one's eyes closed.
0:20:28 > 0:20:33The action of writing has independent neurological basis
0:20:33 > 0:20:36from visual perception of letters.
0:20:37 > 0:20:39Surprising as it may seem,
0:20:39 > 0:20:44reading and writing are controlled by different areas of the brain.
0:20:44 > 0:20:48And because Howard's stroke irreversibly damaged
0:20:48 > 0:20:50the part of his brain used for reading,
0:20:50 > 0:20:53he'll never be able to read in the same way again.
0:20:55 > 0:20:57But this hasn't stopped him.
0:20:57 > 0:20:59Since his stroke, amazingly,
0:20:59 > 0:21:03Howard has painstakingly taught himself to read...
0:21:03 > 0:21:05in an entirely new way.
0:21:07 > 0:21:09Originally, when he looked at a page,
0:21:09 > 0:21:13which might be visually unintelligible to him,
0:21:13 > 0:21:17he would find himself, sometimes unconsciously,
0:21:17 > 0:21:19copying what he saw with his finger.
0:21:19 > 0:21:22- The shapes? - The shapes of the letters.
0:21:22 > 0:21:25This way, he was reading with his finger.
0:21:25 > 0:21:27But now, this has gone a stage further
0:21:27 > 0:21:29and he is reading with his tongue,
0:21:29 > 0:21:34moving his tongue so that it copies the shapes of letters,
0:21:34 > 0:21:37and doing this on the back of his teeth.
0:21:37 > 0:21:39And this is an amazing example
0:21:39 > 0:21:45of one sense moving in for another, and of human adaptability.
0:21:45 > 0:21:48Did you just discover that procedure for yourself?
0:21:48 > 0:21:52Yes, no one suggested it, no. It just seemed to come naturally.
0:21:52 > 0:21:59I think it's evolved to simply making loop-to-loop figures with the tongue.
0:21:59 > 0:22:02Although it's slow, so it may take him a month to read a book
0:22:02 > 0:22:05which he would have read in a couple of nights, he can do it.
0:22:05 > 0:22:08Although he mentioned to me fairly recently
0:22:08 > 0:22:13that he had inadvertently bitten his tongue, while he was eating,
0:22:13 > 0:22:15and he had a sore tongue, and with that,
0:22:15 > 0:22:19became functionally illiterate for two weeks,
0:22:19 > 0:22:20until the tongue got better.
0:22:22 > 0:22:23Before his stroke,
0:22:23 > 0:22:27Howard was famous for his Benny Cooperman series of crime novels.
0:22:29 > 0:22:32Remarkably, only months after losing the ability to read,
0:22:32 > 0:22:35he began work on another novel in the series,
0:22:35 > 0:22:37which has become his most popular to date.
0:22:39 > 0:22:43Writing was one of the things I could still do, so I continued writing.
0:22:43 > 0:22:47Howard used his own experience as inspiration,
0:22:47 > 0:22:50but he did change one crucial detail.
0:22:50 > 0:22:53Private detectives don't have strokes.
0:22:53 > 0:22:57That's one of the rules,
0:22:57 > 0:23:00you have to hit a private detective over the head
0:23:00 > 0:23:03to get him into the same position
0:23:03 > 0:23:07that a stroke serves for the rest of the population.
0:23:13 > 0:23:17It was the ancient Greek physician, Hippocrates, who famously said,
0:23:17 > 0:23:21"It's more important to know what sort of person has a disease
0:23:21 > 0:23:24"than to know what sort of disease a person has."
0:23:24 > 0:23:29It's this thinking that has inspired Sacks throughout his career.
0:23:29 > 0:23:32OK, nice to meet you.
0:23:34 > 0:23:35'I am a neurologist.
0:23:35 > 0:23:39'I explore disorders of the human brain and nervous system.
0:23:39 > 0:23:42'But my approach has a particular emphasis.
0:23:42 > 0:23:46'I am as interested in the person affected by a disorder
0:23:46 > 0:23:48'as I am by the disorder itself.'
0:23:50 > 0:23:51Now, erm...
0:23:54 > 0:23:56Erm... Thanks.
0:24:01 > 0:24:04Oliver Wolf Sacks was born in London in 1933,
0:24:04 > 0:24:06the youngest of four boys.
0:24:06 > 0:24:10Despite being obsessed with chemistry as a child,
0:24:10 > 0:24:14he decided to follow the rest of his family into the medical profession.
0:24:14 > 0:24:18After earning his medical degree from Oxford University,
0:24:18 > 0:24:20he moved to America.
0:24:20 > 0:24:24His first job was at the Beth Abraham Home For Incurables.
0:24:28 > 0:24:31This is where his real love affair with his patients began.
0:24:32 > 0:24:37It's here that he met survivors of the sleepy sickness pandemic.
0:24:37 > 0:24:41Sacks gave them the drug, L-Dopa, which famously brought them
0:24:41 > 0:24:45out of their catatonic states for a brief time.
0:24:56 > 0:24:59Their stories became the subjects of his book, Awakenings,
0:24:59 > 0:25:02which later inspired the Oscar-nominated film.
0:25:04 > 0:25:08You describe yourself as a physician and a storyteller,
0:25:08 > 0:25:11and, of course, that's what has captivated people.
0:25:11 > 0:25:14Well, I love stories and storytelling,
0:25:14 > 0:25:18and my parents, especially my mother...
0:25:18 > 0:25:20My mother was a very good storyteller
0:25:20 > 0:25:25and things would ray out from the particular surgical problem
0:25:25 > 0:25:29or pathology, to the person and their social situation,
0:25:29 > 0:25:32and I would see her talking to the gardener,
0:25:32 > 0:25:35or the dustman, and enchanting them.
0:25:35 > 0:25:40She was a sort of Ancient Mariner. She would hook people with stories.
0:25:40 > 0:25:43It all starts with stories.
0:25:43 > 0:25:47You came from a huge family, and your mother was a surgeon,
0:25:47 > 0:25:50which was unusual for the time.
0:25:50 > 0:25:52How many doctors were there in your family?
0:25:52 > 0:25:55Both my parents were doctors, and as I was growing up,
0:25:55 > 0:25:59my two older brothers were medical students.
0:25:59 > 0:26:04Were cases discussed at the table?
0:26:04 > 0:26:09Constantly, in a way which we, the four sons, loved,
0:26:09 > 0:26:13but which, I think, sometimes terrified,
0:26:13 > 0:26:16or appalled or disgusted strangers.
0:26:16 > 0:26:20My mother, in particular, was a very good storyteller,
0:26:20 > 0:26:22but somehow things would get synchronised
0:26:22 > 0:26:26so that the puss would go with the soup.
0:26:27 > 0:26:35And I partly learned brain anatomy through eating at that time,
0:26:35 > 0:26:40which was long before mad cow disease, when one ate calf brains.
0:26:40 > 0:26:43My mother would say,
0:26:43 > 0:26:47"That finely structured thing, that's cerebellum, try it."
0:26:52 > 0:26:56Since Sacks became a neurologist he's written 11 books
0:26:56 > 0:26:59which have been translated into 24 different languages.
0:27:01 > 0:27:05He receives hundreds of letters every year from all over the world.
0:27:05 > 0:27:08This is a lady with musical hallucinations.
0:27:08 > 0:27:12With the help of Kate Edgar, his close friend and assistant,
0:27:12 > 0:27:14he goes through all of them.
0:27:16 > 0:27:18Do you find people come to you as a last resort?
0:27:18 > 0:27:22They think that maybe you will be able understand their predicament?
0:27:22 > 0:27:27Yeah, I think they do, and it's sometimes heartbreaking,
0:27:27 > 0:27:30because it seems to me
0:27:30 > 0:27:36they've already seen all the best people, and very good people,
0:27:36 > 0:27:42and all sorts of solutions have been attempted and tried,
0:27:42 > 0:27:45and I may have to write back saying,
0:27:45 > 0:27:50"I don't have any magic, I don't think I can help." And, um...
0:27:50 > 0:27:55This, for example, was the situation when some years ago,
0:27:55 > 0:28:00I got a letter from an artist who described having become
0:28:00 > 0:28:03suddenly, totally colour-blind,
0:28:03 > 0:28:05unable to perceive any colours,
0:28:05 > 0:28:09following a head injury in a motor vehicle accident.
0:28:10 > 0:28:13For him, the challenge, as an artist,
0:28:13 > 0:28:16was to live in a suddenly black and white world.
0:28:16 > 0:28:20But trying to show me what things were like,
0:28:20 > 0:28:28he designed an entire room set up for a banquet, as he saw it.
0:28:28 > 0:28:33And...I see Kate gesturing.
0:28:33 > 0:28:35What are you gesturing for?
0:28:35 > 0:28:39Because what we have here is a bowl of fruit painted by him.
0:28:39 > 0:28:40Ah!
0:28:41 > 0:28:42Oh!
0:28:44 > 0:28:50So, the one thing I retrieved from his black and white room
0:28:50 > 0:28:53and banquet was the fruit.
0:28:53 > 0:28:57He said, "You want to know what it's like? It's like this."
0:28:57 > 0:29:03And at that point, he found his world very ugly.
0:29:03 > 0:29:06He didn't know how he could go on as an artist.
0:29:06 > 0:29:11But then, a change occurred with him,
0:29:11 > 0:29:18and what had been, for him, such an impoverished and abnormal
0:29:18 > 0:29:21and ugly world, became a different sort of world.
0:29:21 > 0:29:27Delicate and fine, not spoiled by garish colour.
0:29:30 > 0:29:3215 years ago,
0:29:32 > 0:29:36Sacks travelled the world for a BBC series called The Mind Traveller.
0:29:36 > 0:29:41He met various people with all sorts of conditions, many of whom
0:29:41 > 0:29:45he'd studied over the years and subsequently written about.
0:29:45 > 0:29:47BOAT HORN BLARES
0:29:47 > 0:29:51You feel a deafening noise, how do you sense it?
0:29:51 > 0:29:54One of these case studies was Danny Delcambre.
0:29:54 > 0:29:56Just feel the vibrations.
0:29:57 > 0:29:59At the time Sacks filmed with Danny,
0:29:59 > 0:30:03he was running a popular Cajun restaurant in Seattle,
0:30:03 > 0:30:05but this was no ordinary restaurant.
0:30:05 > 0:30:10To all appearances, it was just like any other good Cajun restaurant.
0:30:11 > 0:30:15Spicy food, sizzling pans, enticing smells.
0:30:17 > 0:30:21Yet there was something different about the place.
0:30:21 > 0:30:27Everyone was communicating in ASL, American sign language.
0:30:28 > 0:30:32The waitress gave Danny orders in ASL.
0:30:32 > 0:30:37The customers were chatting in ASL.
0:30:37 > 0:30:40I like your hearing aid, it's a nice colour.
0:30:40 > 0:30:43The Ragin' Cajun was a restaurant for the deaf.
0:30:50 > 0:30:55Danny is originally from Louisiana, which has the world's highest
0:30:55 > 0:30:59concentration of a rare genetic disorder called Usher Syndrome,
0:30:59 > 0:31:03a condition Danny was born with.
0:31:03 > 0:31:08Usher syndrome destroys two of the senses, hearing and sight.
0:31:08 > 0:31:12So Danny was born deaf, and would eventually go blind.
0:31:12 > 0:31:17Right now, this is about my vision, a square. I'm limited to this.
0:31:17 > 0:31:21When I become fully blind, I don't know what that will be like.
0:31:25 > 0:31:28As Danny and Maria describe their failing sight,
0:31:28 > 0:31:32I try to imagine what the future could hold for them.
0:31:32 > 0:31:34What would it be like,
0:31:34 > 0:31:37no longer being able to see all the beauties of nature around them?
0:31:39 > 0:31:42Within ten years, Danny will be virtually blind.
0:31:49 > 0:31:53Danny has since moved an hour and a half outside of Seattle.
0:31:53 > 0:31:54I went to meet him.
0:31:55 > 0:31:57And with the help of an interpreter,
0:31:57 > 0:32:01found out what had changed for him over the last 15 years.
0:32:01 > 0:32:051996 was when the BBC came, and Oliver Sacks,
0:32:05 > 0:32:08and we made the documentary, which was a very enjoyable,
0:32:08 > 0:32:11interesting experience to do.
0:32:11 > 0:32:14My goal had been to run the restaurant for about ten years.
0:32:14 > 0:32:16That had been my plan.
0:32:16 > 0:32:18I actually made it nine.
0:32:18 > 0:32:20At that point, I sold the business,
0:32:20 > 0:32:22and wasn't sure what I was going to do next,
0:32:22 > 0:32:25if I was going to go into something else, or what.
0:32:25 > 0:32:28About that same time, I met my wife, we got married,
0:32:28 > 0:32:31and lo and behold, we began a family.
0:32:31 > 0:32:35It started to make sense for me to be the stay-at-home parent,
0:32:35 > 0:32:37to become what we call, Mr Mom.
0:32:39 > 0:32:40You guys hungry?
0:32:42 > 0:32:46Since they married, Danny's wife Debbie has learned sign language.
0:32:46 > 0:32:49And the children, who are unaffected by Usher syndrome,
0:32:49 > 0:32:53also talk to their father through basic sign language.
0:32:56 > 0:33:00I did everything - the diaper changing, the feeding, the works,
0:33:00 > 0:33:02playing with the children as they've grown.
0:33:02 > 0:33:05And, oh, my goodness, that is a busy job.
0:33:05 > 0:33:09I hadn't quite realised it, it is not an easy task.
0:33:09 > 0:33:12I'm just interested to know where Danny's Usher Syndrome is today?
0:33:12 > 0:33:17In this room, for instance, what can you see around us?
0:33:20 > 0:33:25It's a pretty small tunnel. Looking at the interpreter, I can see...
0:33:25 > 0:33:29I can't see anything on either side of her at all,
0:33:29 > 0:33:33but I can see from her shoulders, inside of her shoulders,
0:33:33 > 0:33:37most of her face, and down just the top of her chest,
0:33:37 > 0:33:40sort of that area, that little circle or square.
0:33:40 > 0:33:43And from this distance, this is a good distance for me.
0:33:43 > 0:33:47If she were to come closer, I couldn't see enough of her.
0:33:47 > 0:33:50But I'm functionally blind in the right eye, I have light perception,
0:33:50 > 0:33:55but that is it, it's basically all dark with a little pinpoint of light.
0:33:55 > 0:34:01And then at night, or if the light is dim, I'm basically blind.
0:34:08 > 0:34:10He's still got...
0:34:10 > 0:34:12He's still got some vision.
0:34:12 > 0:34:18I was wondering, yes. It's probably very, very narrowed.
0:34:18 > 0:34:20Very, very narrowed indeed.
0:34:20 > 0:34:24And yet, there's a sort of optimism in Danny,
0:34:24 > 0:34:30as his wife acknowledged to me, that he's not really prepared to concede.
0:34:30 > 0:34:33Yes, perhaps there's all the difference
0:34:33 > 0:34:36between a little vision and no vision.
0:34:38 > 0:34:42He's a very resilient person, has a lovely sense of humour,
0:34:42 > 0:34:44but he will always have language.
0:34:44 > 0:34:49Even when he can no longer see, one can have sign-language on the hand.
0:34:51 > 0:34:55When Sacks filmed with Danny, he met a whole community of people
0:34:55 > 0:34:58with Usher Syndrome at a summer camp.
0:34:59 > 0:35:02Here he witnessed the deaf-blind for the first time
0:35:02 > 0:35:07and how they communicated with tactile sign language.
0:35:07 > 0:35:10Denied sight as well as hearing,
0:35:10 > 0:35:13these people were talking with touch.
0:35:14 > 0:35:18I'm amazed at how much can be got sometimes
0:35:18 > 0:35:23from just apparently feeling the wrist of the signing hand.
0:35:23 > 0:35:27It's obviously a complete communication.
0:35:28 > 0:35:33What else has so fascinated me has been the hunger for communication,
0:35:33 > 0:35:35the hunger for language.
0:35:35 > 0:35:38The world which can't be directly perceived,
0:35:38 > 0:35:42which can't be seen or heard, must be narrated.
0:35:42 > 0:35:46You can sometimes forget how central language is to being human.
0:35:46 > 0:35:49You may have to come to deaf people, especially these Deaf-Blind people
0:35:49 > 0:35:52to see that human beings can't live without language,
0:35:52 > 0:35:56can't live without communication, and they will create it somehow.
0:36:01 > 0:36:04As Danny's sight fails, he's relying more and more
0:36:04 > 0:36:07on tactile sign language.
0:36:07 > 0:36:09He'll eventually only see through touch.
0:36:11 > 0:36:15But whilst he still has some vision left, he's taken up a new interest.
0:36:18 > 0:36:21Of all things, photography.
0:36:22 > 0:36:25As I watched him photograph his children,
0:36:25 > 0:36:28I realized it helped him see things clearer.
0:36:28 > 0:36:30He could capture a still frame
0:36:30 > 0:36:33of something that most of the time was blurred.
0:36:33 > 0:36:37He was capturing what he loved, things worth seeing
0:36:37 > 0:36:38and honing in on.
0:36:44 > 0:36:46He told me how he spent hours in his garden,
0:36:46 > 0:36:51photographing details of flowers and the wildlife.
0:36:51 > 0:36:55All small, beautiful creations.
0:36:55 > 0:36:57Some of my favourite shots
0:36:57 > 0:36:59are of the hummingbirds out here in our backyard.
0:36:59 > 0:37:02I have to tell you, it was a trick figuring out
0:37:02 > 0:37:05how to take a picture of a hummingbird, because they move
0:37:05 > 0:37:08and I didn't want them just at the feeder
0:37:08 > 0:37:10because that's just not natural,
0:37:10 > 0:37:13I wanted them at the real flowers so I would just wait
0:37:13 > 0:37:19and wait and wait and hold very still and, lo and behold,
0:37:19 > 0:37:21I got some very nice shots.
0:37:23 > 0:37:28Some of them very close where you can really see those long, long beaks.
0:37:30 > 0:37:33I wasn't very good at it at first but now I've got some really,
0:37:33 > 0:37:34really beautiful pictures.
0:37:36 > 0:37:41Have you transferred your love of cooking to your love of photography?
0:37:41 > 0:37:44Yeah, a little bit. That's what happened, I think.
0:37:44 > 0:37:49Whether I could ever make a business out of it, selling my pictures or what not, I don't know.
0:37:49 > 0:37:51I'm seeing in you, Danny, a camera-obsessive.
0:37:51 > 0:37:56I think that's right. Yes. And I'm fascinated at some of the cameras you all have here, my goodness!
0:37:56 > 0:38:00They far outstrip anything I could afford at this point.
0:38:03 > 0:38:07I left Seattle surprised yet again by the resilience
0:38:07 > 0:38:10of human beings and the resources they can command
0:38:10 > 0:38:14both individually and communally.
0:38:14 > 0:38:17At times, not knowing sign-language,
0:38:17 > 0:38:21I had felt that I was the only impaired person there.
0:38:26 > 0:38:30But the greatest revelation was the beautiful language of touch.
0:38:32 > 0:38:35I would not have thought that touch alone
0:38:35 > 0:38:39could be an adequate instrument for understanding a language,
0:38:39 > 0:38:40but I was mistaken.
0:38:45 > 0:38:47Yet, perhaps I should not be astonished.
0:38:47 > 0:38:51The human brain, after all, is the most wonderful
0:38:51 > 0:38:53and adaptable creation in the universe.
0:39:01 > 0:39:05We are sensory creatures, it's how we make sense of the world,
0:39:05 > 0:39:08and evolution has played a big part
0:39:08 > 0:39:11in shaping our perception of what's out there.
0:39:17 > 0:39:20The brain of all animals evolved to see the world
0:39:20 > 0:39:23in a way that was most useful for survival.
0:39:26 > 0:39:28For our primate ancestors,
0:39:28 > 0:39:31the ability to distinguish reds and oranges
0:39:31 > 0:39:35and thus the ripest fruit and leaves, was a huge advantage.
0:39:35 > 0:39:38So colour vision developed in primates
0:39:38 > 0:39:41where it's absent in most other mammals.
0:39:43 > 0:39:47Similarly, forward-looking eyes allow good depth perception,
0:39:47 > 0:39:50vital for swinging through the trees.
0:39:52 > 0:39:56In general, prey animals have to have a panoramic vision
0:39:56 > 0:40:01and be on the lookout for attackers anywhere.
0:40:01 > 0:40:08Predatory animals need to focus in. Some animals have both.
0:40:08 > 0:40:12My favourite, cuttlefish, and there are pictures of cuttlefish
0:40:12 > 0:40:16all around the place. I am very fond of cuttlefish,
0:40:16 > 0:40:23but cuttlefish eyes are usually set up for panoramic vision.
0:40:23 > 0:40:25But when a cuttlefish goes in for the kill,
0:40:25 > 0:40:29the eyes can be rotated around and then you have a big overlap of the visual fields.
0:40:32 > 0:40:36And stereo vision and then they shoot out these tentacles.
0:40:40 > 0:40:42And no fish will escape them then.
0:40:48 > 0:40:51Stereo vision has its benefits for us, too.
0:40:51 > 0:40:55It's our principal way of perceiving depth.
0:40:55 > 0:41:01This is achieved by our two eyes receiving subtly different images.
0:41:01 > 0:41:03The brain and then takes these images
0:41:03 > 0:41:06and in a way that's still not fully understood,
0:41:06 > 0:41:08mysteriously fuses them into one.
0:41:08 > 0:41:11This is how we perceive depth.
0:41:14 > 0:41:17I think you should put the glasses on, Sue.
0:41:17 > 0:41:19When most of us view the world we see depth
0:41:19 > 0:41:22and three-dimensionality.
0:41:23 > 0:41:28But when we go to the cinema and see a 3D film, depth is exaggerated.
0:41:28 > 0:41:31This is a novel experience for Sue Barry.
0:41:31 > 0:41:32Whoa!
0:41:34 > 0:41:36It's only in the last few years
0:41:36 > 0:41:41that she's been able to see the three-dimensionality of 3D films...
0:41:43 > 0:41:48- ..And perceive depth in her everyday life.- It's wonderful.
0:41:48 > 0:41:49The beaks and everything!
0:41:53 > 0:41:56Well everything is kind of on top of me now.
0:41:56 > 0:41:59The scenes with the rifles coming out and so on.
0:41:59 > 0:42:06It just pops out right at you, plus things go further back in space as well.
0:42:06 > 0:42:08So it's like, wow, look at that!
0:42:11 > 0:42:13So in a sense, for you, this 3D experience,
0:42:13 > 0:42:16that's what the world out there is like for you?
0:42:16 > 0:42:18That's right. That's right.
0:42:18 > 0:42:22Every day it's sort of like a 3D movie and I'm constantly surprised.
0:42:23 > 0:42:26I get a sort of butterflies-in-the-stomach kind of feeling.
0:42:26 > 0:42:31- Like a whole visceral response.- Mm. - My whole body reacts to it.
0:42:31 > 0:42:34It's like, "Wow! Look at that! It's different."
0:42:36 > 0:42:38'Because Sue was born cross-eyed,
0:42:38 > 0:42:41'she saw a very different view through each eye.
0:42:41 > 0:42:45'This created a confusing double vision.
0:42:45 > 0:42:51'So her brain adapted by taking in information from only one eye at a time,
0:42:51 > 0:42:55'rapidly switching between the two.
0:42:55 > 0:42:57'This meant Sue had no stereo vision -
0:42:57 > 0:43:01'her world was flat and two-dimensional.
0:43:02 > 0:43:06'As a child, she had operations to realign her eyes
0:43:06 > 0:43:09'but it didn't change the way she viewed the world.
0:43:09 > 0:43:11'It was still flat.'
0:43:11 > 0:43:14Basically, when I looked at something in the past...
0:43:14 > 0:43:16Let's say I was looking at your face.
0:43:16 > 0:43:19I would see your face in detail
0:43:19 > 0:43:24and that stuff behind you, would just sort of appear in one flat plane.
0:43:24 > 0:43:28And now, everything's in layers and layers and layers of space.
0:43:30 > 0:43:35'Sue grew up and became a neurobiologist.
0:43:35 > 0:43:39'Then, in her late 40s, something remarkable happened.
0:43:40 > 0:43:42'Sue acquired stereo vision.'
0:43:44 > 0:43:48So what really surprised me was that everything was in 3D.
0:43:48 > 0:43:54The whole world was in 3D. Even things that look ordinary were suddenly extraordinarily different.
0:43:54 > 0:43:56Take, for example, the bumper of this car.
0:43:56 > 0:44:00It's really coming out at me. It's popping out at me - boom! Like this.
0:44:00 > 0:44:02I never saw it that way before.
0:44:02 > 0:44:06Sure, I knew the bumper of the car was in front of the dashboard.
0:44:06 > 0:44:09I could tell from various other kinds of cues,
0:44:09 > 0:44:11but to actually experience it,
0:44:11 > 0:44:15to have this real sense of it - boom - popping out at me,
0:44:15 > 0:44:18was really different to the way I'd seen the world before.
0:44:18 > 0:44:20- Was it quite shocking, in a way? - It was.
0:44:20 > 0:44:24I kept looking at things, like doorknobs or sink faucets,
0:44:24 > 0:44:27all of a sudden, like, popping out at me,
0:44:27 > 0:44:29and I would always do a double-take.
0:44:31 > 0:44:36'In 1965, two Nobel Prize-winning scientists, Hubel and Wiesel,
0:44:36 > 0:44:40'experimenting with kittens, got results that suggested
0:44:40 > 0:44:46'that if a child's cross eyes were not realigned within one or two years of birth -
0:44:46 > 0:44:51'the so-called critical period, that child would always lack stereo vision.
0:44:52 > 0:44:55'Sue, the neurobiologist, was familiar with this research,
0:44:55 > 0:45:00'and was reluctant to tell anyone about her own extraordinary breakthrough.'
0:45:00 > 0:45:03I was afraid they would say, "Oh, it's impossible!
0:45:03 > 0:45:06"You must be delusional. You must making it up."
0:45:06 > 0:45:08Or, "So what's the big deal? If I close one eye,
0:45:08 > 0:45:11"the world doesn't look all that different."
0:45:11 > 0:45:13The reason why you can do this, cover one eye,
0:45:13 > 0:45:17and the world won't look different is that you've always had stereo vision,
0:45:17 > 0:45:23so even if you momentarily close one eye, your brain fills in the missing stereo information.
0:45:23 > 0:45:26But if you've never had it and then you acquire it,
0:45:26 > 0:45:31after half a century of living, it is a major revelation.
0:45:31 > 0:45:34So I thought about this for about...
0:45:34 > 0:45:38almost three years, and finally one night,
0:45:38 > 0:45:42when I thought I was just going to burst, I sat down with my laptop
0:45:42 > 0:45:45and I pounded out a letter to Oliver Sacks, because I thought
0:45:45 > 0:45:52if anybody might at least read my letter and consider my story,
0:45:52 > 0:45:53maybe it would be Dr Sacks.
0:45:53 > 0:46:00Well, I was fascinated by her letter and I asked if I could visit.
0:46:00 > 0:46:04I love extended house calls, getting a letter which excites me
0:46:04 > 0:46:08and then going off on a sort of neurological adventure.
0:46:08 > 0:46:11I confess I was a little doubtful.
0:46:11 > 0:46:13I wondered if she could be kidding herself.
0:46:13 > 0:46:20I took some pictures which gave no clue other than stereo to their depth.
0:46:20 > 0:46:24She did well with this and I was convinced this was the genuine article,
0:46:24 > 0:46:29and we went for a walk and this was a lovely example, in a way,
0:46:29 > 0:46:33of the innocence of vision, almost a child's vision,
0:46:33 > 0:46:38now being experienced by an adult who never had it before.
0:46:38 > 0:46:41So Sue was absurdly delighted by everything.
0:46:45 > 0:46:49When I first began, let's say, to see a tree in 3D,
0:46:49 > 0:46:54the outer branches circle around and capture whole volumes of space
0:46:54 > 0:46:57within which the inner branches permeate.
0:46:58 > 0:47:03To me, that was a completely novel revelation.
0:47:03 > 0:47:06In the past, trees just looked sort of flat, like they would
0:47:06 > 0:47:10in a children's drawing, even though I knew they weren't flat.
0:47:10 > 0:47:13Knowing and seeing are completely different.
0:47:16 > 0:47:19People who have stereo don't know what they have,
0:47:19 > 0:47:23and the people who don't have stereo don't know what they're missing.
0:47:23 > 0:47:27As many as 500 million people worldwide,
0:47:27 > 0:47:32for one reason or another, have little or no stereo vision.
0:47:32 > 0:47:35For Sue, it wasn't initially a conscious decision
0:47:35 > 0:47:36to try and acquire it.
0:47:36 > 0:47:39As far as she was concerned, she never could.
0:47:39 > 0:47:41But then, in her late 40s,
0:47:41 > 0:47:45she started getting other problems with her vision.
0:47:45 > 0:47:47I'll just have you look straight ahead.
0:47:49 > 0:47:53So she booked in to see a developmental optometrist.
0:47:53 > 0:47:58I went to see Dr Theresa Ruggiero when I was 48 years old,
0:47:58 > 0:47:59not to develop stereo vision
0:47:59 > 0:48:05but because my vision had become so jittery.
0:48:05 > 0:48:08If you have two eyes and both of them are taking in information,
0:48:08 > 0:48:10which was the case for Sue,
0:48:10 > 0:48:14but they're not both taking in information at the same time,
0:48:14 > 0:48:17what you have is a constant rivalry or sort of competition
0:48:17 > 0:48:19between the information coming into the eyes.
0:48:19 > 0:48:23And that creates instability and confusion.
0:48:25 > 0:48:27So now look at the middle bead.
0:48:27 > 0:48:29Having assessed Sue's vision,
0:48:29 > 0:48:32Dr Theresa Ruggiero spent a year working with Sue,
0:48:32 > 0:48:35doing simple vision exercises again and again
0:48:35 > 0:48:38until Sue could master them.
0:48:38 > 0:48:41The aim of these exercises was to teach Sue's brain
0:48:41 > 0:48:46to see through both eyes at the same time, something she had never done.
0:48:46 > 0:48:53Many people have, and many children will have, surgery to try to correct that, just as you had surgery.
0:48:53 > 0:48:56So why doesn't surgery solve it?
0:48:56 > 0:49:00Surgery alone is not enough because what it does is it disconnects
0:49:00 > 0:49:05and reconnects the muscles of the eyes, but without that information being provided to the brain.
0:49:05 > 0:49:09The problem is not muscle-based, the problem originates up here.
0:49:09 > 0:49:12It's a brain problem. And so what has to happen is you have to work
0:49:12 > 0:49:17with the visual pathways that control where the eyes are aiming.
0:49:18 > 0:49:22For a year, Sue worked on various simple yet highly effective
0:49:22 > 0:49:27vision exercises until she could, without thinking about it,
0:49:27 > 0:49:30fuse the images from both eyes at the same time.
0:49:30 > 0:49:35This stopped her jittery vision and gave her something
0:49:35 > 0:49:40the rest of us take for granted - three-dimensional stereo vision.
0:49:40 > 0:49:43You're taking those two different sets of information
0:49:43 > 0:49:48and fusing them and seeing it as one combined image.
0:49:48 > 0:49:49- Do you see that?- Yes.
0:49:49 > 0:49:51So you're seeing a virtual image.
0:49:51 > 0:49:54Show me with your hand where it seems to be in space.
0:49:54 > 0:49:58- That's where it is.- Yeah, exactly.
0:49:58 > 0:50:02- In fact, how dare anyone say it isn't?- Yeah, exactly.
0:50:02 > 0:50:05And the fact is it's all going up here.
0:50:05 > 0:50:09That's right, vision is a brain process, vision does not happen in the eyeballs.
0:50:09 > 0:50:11That the tip of the iceberg, the eyeballs.
0:50:15 > 0:50:20Every week for about a year I would pass this tree and,
0:50:20 > 0:50:24with each passing week, it became more and more three-dimensional.
0:50:24 > 0:50:29So this tree was almost like a barometer of the change in my vision.
0:50:29 > 0:50:31It's such a spectacular tree.
0:50:31 > 0:50:37And you'll also notice, as you move, you get an increase in that sense of three dimensions.
0:50:37 > 0:50:40That is due to something called motion parallax.
0:50:40 > 0:50:45After I gained stereo, I found myself spending a lot of time doing
0:50:45 > 0:50:50just what we're doing right now, which is just rocking back and forth under a tree
0:50:50 > 0:50:52and enjoying all the depth that I could see.
0:50:52 > 0:50:56- Do you know, I could get used to this?- Yeah.
0:50:56 > 0:51:02It's something we could do well into retirement.
0:51:05 > 0:51:08After her initial reluctance to tell anyone,
0:51:08 > 0:51:12Sue is now very open about her new stereo vision.
0:51:12 > 0:51:15She even contacted David Hubel.
0:51:15 > 0:51:18He's since followed Sue's case with great interest
0:51:18 > 0:51:21and continues to explore the implications of her
0:51:21 > 0:51:27development of stereo vision nearly 50 years after the critical period.
0:51:28 > 0:51:31In contrast to Sue,
0:51:31 > 0:51:35Sacks was acutely aware of his stereo vision from an early age.
0:51:35 > 0:51:38As a boy, he loved using stereo viewers,
0:51:38 > 0:51:40and as soon as he discovered photography
0:51:40 > 0:51:45he was taking stereo photographs and experimenting with making his own viewers.
0:51:47 > 0:51:51Even as a school kid, I would sometimes be caught closing one eye
0:51:51 > 0:51:54and then the other and asked what I was doing.
0:51:54 > 0:51:57I said I was seeing how the world flattened.
0:51:57 > 0:52:00And I was told to spend my time more usefully,
0:52:00 > 0:52:05but I loved playing with stereoscopy and making hyper stereoscopes.
0:52:05 > 0:52:08I think I partly fell in love with America books
0:52:08 > 0:52:12of stereo views of the Grand Canyon and Yosemite.
0:52:12 > 0:52:18So this is a View-Master, which must be very familiar to you from your childhood.
0:52:18 > 0:52:19I adored them.
0:52:19 > 0:52:21You can have a look.
0:52:23 > 0:52:27I think we've tried to get some great American views for you.
0:52:27 > 0:52:30OK. Well, there's some very beautiful mountains,
0:52:30 > 0:52:34snow-covered with a lake in front of them.
0:52:34 > 0:52:37I would wonder whether it was a volcanic lake.
0:52:37 > 0:52:40This is the American west or the north-west.
0:52:40 > 0:52:43This is what I fell in love with.
0:52:43 > 0:52:47The old days, if I looked through this I would have seen
0:52:47 > 0:52:49the lake moving away
0:52:49 > 0:52:56and the mountains palpably further away.
0:52:56 > 0:53:03I would have been intensely conscious of the space between the foreground and the far ground,
0:53:03 > 0:53:06whereas now it's all flat.
0:53:13 > 0:53:19Six years ago, Oliver developed a large blind-spot in his right eye.
0:53:19 > 0:53:21He went to see an opthalmologist
0:53:21 > 0:53:25and his worst nightmare was confirmed:
0:53:25 > 0:53:28he had a malignant tumour.
0:53:28 > 0:53:31Despite radiation and laser treatment,
0:53:31 > 0:53:35Sacks eventually lost all sight in his right eye,
0:53:35 > 0:53:40and with it the stereo vision that he'd cherished since childhood.
0:53:42 > 0:53:47Given how much you relish that stereo world,
0:53:47 > 0:53:49how are you coping without it?
0:53:49 > 0:53:53There is an overwhelming sense of loss,
0:53:53 > 0:53:56and I occasionally have dreams
0:53:56 > 0:54:00in which it seems to me that I have stereo,
0:54:00 > 0:54:05in particular the dreams, I am looking into a stereoscope.
0:54:05 > 0:54:11And when I wake up and see the fan in my bedroom
0:54:11 > 0:54:16about to hit the bedside lamp, I know they are 6ft apart
0:54:16 > 0:54:22but for me they are transposed and conflated onto the same plane.
0:54:22 > 0:54:24and I miss stereo,
0:54:24 > 0:54:27not so much in my day-to-day functioning as just
0:54:27 > 0:54:31in the richness and beauty of the world.
0:54:31 > 0:54:34So you have your stereo vision in your dreams then?
0:54:34 > 0:54:39I think I do, in so far as one has any descriptions of dreams
0:54:39 > 0:54:43that are reliable. I think I've had it in dreams and I think
0:54:43 > 0:54:48I've had it, or a hallucination of it,
0:54:48 > 0:54:51when I've smoked some pot.
0:54:51 > 0:54:56- You'd better smoke a bit more pot then!- Perhaps I should.
0:54:58 > 0:55:00Oliver Sacks is now 77.
0:55:00 > 0:55:06He still sees patients and publishes a new book every couple of years.
0:55:06 > 0:55:10He loves plants, cuttlefish and the periodic table.
0:55:10 > 0:55:15He swims almost every day and has done so for decades.
0:55:28 > 0:55:31Subtitles by Red Bee Media Ltd
0:55:31 > 0:55:34E-mail subtitling@bbc.co.uk