Serendipity Out of one's depth

THIS afternoon, while reading Steven Pinker's How The Mind Works, I suddenly uttered a stream of expletives. After almost a decade of failure, I had at last witnessed my first Magic-Eye image.

The principle of the autostereogram, as it is officially called, was discovered in the 1840s by the Scottish scientist Sir David Brewster. He had studied optics for many years, and was responsible for inventing both the kaleidoscope, a big hit among Victorian children, and the lenticular stereo-scope, which became a craze after it fascinated Queen Victoria. The stereo-scope generates a 3-D effect when the viewer looks through the eyepieces, but the beauty of the autostereogram is that a 3-D image is created without any external help - the viewer simply stares at the autostereogram and uses internal brain machinery to give the image depth.

The brain is continually trying to convert signals from the two eyeballs into a meaningful image. For example, if both eyes are focused on a single dot, then the dot will make one signal in each eyeball, and the brain combines the signal in each eyeball in order to work out the exact location of the dot.

However, if both eyes are staring at two dots, say an inch apart and 12 inches from the face, then the situation becomes much more complicated. The two dots create two signals in each eyeball, and the brain does not know which dot in one eyeball is related to which dot in the other eyeball. This ambiguity means that the brain can interpret the information in two ways. It thinks that either the dots are roughly the same distance away, which would be accurate, or that one dot is closer than the other, which results in an artificial sense of depth. The latter interpretation gives the Magic-Eye effect.

Brewster first became aware of how this con- fusion can generate an autostereogram when he was staring at some wall-paper that consisted of a repeated pattern. Instead of interpreting the repeated pattern as flat, his brain mismatched the signals in his eyeballs and created 3-D wallpaper. Men standing at urinals, staring at a wall covered in patterned tiles, sometimes experience a similar accidental autostereogram.

The vast majority of brains try to force eyeball signals into a 3-D framework, which is why a 2-D pattern sometimes seems to have depth. However, roughly 2 per cent of brains are completely lacking in stereovision. Furthermore, another 6 per cent of brains have partly defective stereovision, and those people may or may not be able to appreciate autostereograms.

If you are unsure as to whether or not you have experienced the Magic- Eye effect, then I would offer a remark made by autostereogram expert Chris Tyler: "Stereovision is like love. If you're not sure, then you're not experiencing it".

Arts and Entertainment
Nick Frost will star in the Doctor Who 2014 Christmas special

TV
Arts and Entertainment
Friends is celebrating its 20th anniversary this year
TV
Arts and Entertainment
A spell in the sun: Emma Stone and Colin Firth star in ‘Magic in the Moonlight’
filmReview: Magic In The Moonlight
Arts and Entertainment
Ben Whishaw is replacing Colin Firth as the voice of Paddington Bear

TV
Arts and Entertainment
Actor and director Zach Braff

TV
PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment

TV
Arts and Entertainment
Meera Syal was a member of the team that created Goodness Gracious Me

TV
Arts and Entertainment
The former Doctor Who actor is to play a vicar is search of a wife

film
Arts and Entertainment

music
Arts and Entertainment
Pointless host Alexander Armstrong will voice Danger Mouse on CBBC

TV
Arts and Entertainment
Pharrell dismissed the controversy surrounding

music
Arts and Entertainment
Jack Huston is the new Ben-Hur

film
Arts and Entertainment

TV
Arts and Entertainment
Cara Delevingne modelling

film
Arts and Entertainment
Emma Thompson and Bryn Terfel are bringing Sweeney Todd: The Demon Barber of Fleet Street to the London Coliseum

theatre
Arts and Entertainment
Sheridan Smith as Cilla Black

TV
Arts and Entertainment
Robin Thicke's video for 'Blurred Lines' has been criticised for condoning rape

Robin Thicke admits he didn't write 'Blurred Lines'

music
Arts and Entertainment
While many films were released, few managed to match the success of James Bond blockbuster 'Skyfall'

film
Arts and Entertainment
Matt Damon as Jason Bourne in The Bourne Ultimatum (2007)

film
Arts and Entertainment
Sheridan Smith as Cilla Black

Review: Cilla, ITV TV
Arts and Entertainment

TV
Arts and Entertainment
Tom Hardy stars with Cillian Murphy in Peaky Blinders II

TV
Arts and Entertainment

art
Arts and Entertainment
Keira Knightley and Benedict Cumberbatch star in the Alan Turing biopic The Imitation Game

film
Arts and Entertainment
Kanye West is on his 'Yeezus' tour at the moment

Music
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    Scottish referendum: The Yes vote was the love that dared speak its name, but it was not to be

    Despite the result, this is the end of the status quo

    Boyd Tonkin on the fall-out from the Scottish referendum
    Manolo Blahnik: The high priest of heels talks flats, Englishness, and why he loves Mary Beard

    Manolo Blahnik: Flats, Englishness, and Mary Beard

    The shoe designer who has been dubbed 'the patron saint of the stiletto'
    The Beatles biographer reveals exclusive original manuscripts of some of the best pop songs ever written

    Scrambled eggs and LSD

    Behind The Beatles' lyrics - thanks to Hunter Davis's original manuscript copies
    'Normcore' fashion: Blending in is the new standing out in latest catwalk non-trend

    'Normcore': Blending in is the new standing out

    Just when fashion was in grave danger of running out of trends, it only went and invented the non-trend. Rebecca Gonsalves investigates
    Dance’s new leading ladies fight back: How female vocalists are now writing their own hits

    New leading ladies of dance fight back

    How female vocalists are now writing their own hits
    Mystery of the Ground Zero wedding photo

    A shot in the dark

    Mystery of the wedding photo from Ground Zero
    His life, the universe and everything

    His life, the universe and everything

    New biography sheds light on comic genius of Douglas Adams
    Save us from small screen superheroes

    Save us from small screen superheroes

    Shows like Agents of S.H.I.E.L.D are little more than marketing tools
    Reach for the skies

    Reach for the skies

    From pools to football pitches, rooftop living is looking up
    These are the 12 best hotel spas in the UK

    12 best hotel spas in the UK

    Some hotels go all out on facilities; others stand out for the sheer quality of treatments
    These Iranian-controlled Shia militias used to specialise in killing American soldiers. Now they are fighting Isis, backed up by US airstrikes

    Widespread fear of Isis is producing strange bedfellows

    Iranian-controlled Shia militias that used to kill American soldiers are now fighting Isis, helped by US airstrikes
    Topshop goes part Athena poster, part last spring Prada

    Topshop goes part Athena poster, part last spring Prada

    Shoppers don't come to Topshop for the unique
    How to make a Lego masterpiece

    How to make a Lego masterpiece

    Toy breaks out of the nursery and heads for the gallery
    Meet the ‘Endies’ – city dwellers who are too poor to have fun

    Meet the ‘Endies’ – city dwellers who are too poor to have fun

    Urbanites are cursed with an acronym pointing to Employed but No Disposable Income or Savings
    Paisley’s decision to make peace with IRA enemies might remind the Arabs of Sadat

    Ian Paisley’s decision to make peace with his IRA enemies

    His Save Ulster from Sodomy campaign would surely have been supported by many a Sunni imam