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TED2004

Al Seckel: Visual illusions that show how we (mis)think

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Al Seckel, a cognitive neuroscientist, explores the perceptual illusions that fool our brains. Loads of eye tricks help him prove that not only are we easily fooled, we kind of like it.

- Master of visual illusions
Al Seckel explored how eye tricks can reveal the way the brain processes visual information -- or fails to do so. Among his other accomplishments: He co-created the Darwin Fish. Full bio

We're going to talk -- my -- a new lecture, just
00:25
for TED -- and I'm going show you some illusions
00:26
that we've created for TED, and I'm going to try
00:29
to relate this to happiness. What I was thinking
00:32
about with happiness is, what gives happiness --
00:34
or happiness, which I equate with joy in my
00:37
particular area, and I think there's something very
00:41
fundamental. And I was thinking about this. And
00:43
it's in terms of both illusions and movies that we
00:47
go see and jokes and magic shows is that there's
00:51
something about these things where our
00:55
expectations are violated in some sort of pleasing
00:57
way. You go see a movie. And it has an unexpected
01:01
twist -- something that you didn't expect -- and
01:04
you find a joyful experience. You look at those
01:07
sort of illusions in my book and it's not as what
01:10
you'd expect. And there's something joyful about
01:13
it. And it's the same thing with jokes and all
01:15
these sorts of things. So, what I'm going to try
01:18
and do in my lecture is go a little bit further
01:21
and see if I can violate your expectations in a
01:24
pleasing way. I mean, sometimes expectations that
01:27
are violated are not pleasant, but I'm going to try
01:30
to do it in a pleasant way, in a very primal way,
01:32
so I can make the audience here happy.
01:35
So I'm going to show you some ways that we can
01:37
violate your expectations. First of all, I want to
01:40
show you the particular illusion here. I want you
01:43
first of all when it pops up on the screen to
01:46
notice that the two holes are perpendicular to
01:49
each other. These are all perceptual tricks. These
01:51
are real objects that I'm going to show you. Now
01:55
I'm going to show you how it is done. I've looped
02:06
the film here so you can get a very interesting
02:09
experience. I want you to see how this illusion is
02:11
constructed, and it's going to rotate so you see
02:14
that it's inside out. Now watch, as it rotates
02:17
back, how quickly your perception snaps. OK now.
02:20
Watch it as it rotates back again. And this is a very
02:26
bright audience, all right? See if you can stop it
02:29
from happening, even though you know 100 percent it's
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true that -- bam! You can't undo it. What does
02:35
that tell you about yourselves? We're going to do
02:40
it again. No doubt about it. See if you can stop
02:44
it from happening. No. It's difficult.
02:47
And we can violate your expectations in a whole
02:54
variety of ways about representation, about shape,
02:57
about color and so forth and it's very primal. And
03:00
it's an interesting question to ponder, why these
03:03
things -- we find these things joyful. Why would
03:06
we find them joyful? So, here's something that
03:10
Lionel did a while ago. I like these sort of
03:13
little things like this.
03:15
Again, this is not an optical trick. This is what
03:19
you would see. In other words, it's not a camera
03:22
cut. It's a perceptual trick.
03:42
OK. We can violate your expectations about
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shape.
03:57
We can violate your expectations on representation
04:16
-- what an image represents. What do you see here?
04:20
How many of you here see dolphins? Raise your hand
04:25
if you see dolphins. OK, those people who raised
04:32
their hands, afterwards, the rest of the audience,
04:36
go talk to them, all right? Actually, this is the
04:38
best example of priming by experience that I know.
04:42
If you are a child under the age of 10 who
04:46
haven't been ruined yet, you will look at this
04:50
image and see dolphins. Now, some of you adults
04:53
here are saying, "What dolphins? What dolphins?"
04:57
But in fact, if you reversed the figure ground --
04:59
in other words, the dark areas here -- I forgot to
05:02
ask for a pointer -- but if you reverse it, you'll
05:05
see a whole series of little dolphins. By the way,
05:07
if you're also a student at CalTech -- they also
05:10
tend to just see the dolphins. It's based on
05:13
experience.
05:16
Now, something like this can be used because this
05:20
is after all talk about design, too. This was
05:23
done by Saatchi and Saatchi, and they actually got
05:25
away with this ad in Australia. So, if you look at
05:28
this ad for beer, all those people are in sort of
05:31
provocative positions. But they got it passed, and
05:36
actually won the Clio awards, so it's funny how you can do
05:39
these things.
05:43
Remember that sort of, um. This is the joke I did
05:44
when the Florida ballot was going around. You
05:52
know, count the dots for Gore; count the dots for
05:56
Bush; count 'em again ...
05:58
You can violate your expectations about
06:03
experience. Here is an outside water fountain that
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I created with some friends of mine, but you can
06:13
stop the water in drops and -- actually make all
06:15
the drops levitate. This is something we're
06:18
building for, you know, amusement parks and that
06:24
kind of stuff.
06:26
Now let's take a static image. Can you see this?
06:27
Do you see the middle section moving down and the
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outer sections moving up? It's completely static.
06:34
It's a static image. How many people see this
06:38
illusion? It's completely static.
06:40
Right. Now, when -- it's interesting that when we
06:46
look at an image we see, you know, color, depth,
06:49
texture. And you can look at this whole scene and
06:53
analyze it. You can see the woman is in closer than
06:56
the wall and so forth. But the whole thing is
06:59
actually flat. It's painted. It's trompe l'oeil.
07:01
And it was such a good trompe l'oeil that people
07:06
got irritated when they tried to talk to the
07:08
woman and she wouldn't respond.
07:10
Now, you can make design mistakes. Like this
07:15
building in New York. So that when you see it from
07:19
this side, it looks like the balconies tilt up,
07:25
and when you walk around to the other side it
07:28
looks like the balconies go down. So there are
07:30
cases where you have mistakes in design that
07:35
incorporate illusions.
07:37
Or, you take this particular un-retouched
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photograph. Now, interestingly enough, I get a lot
07:41
of emails from people who say, "Is there any
07:49
perceptual difference between males and females?"
07:51
And I really say, "No." I mean, women can navigate
07:56
through the world just as well as males can -- and
07:58
why wouldn't they? However, this is the one
08:01
illusion that women can consistently do better
08:03
than males: in matching which head because they
08:06
rely on fashion cues. They can match the hat.
08:09
Okay, now getting to a part -- I want to show
08:15
design in illusions. I believe that the first
08:17
example of illusions being used purposely was by
08:20
da Vinci in this anamorphic image of an eye. So
08:25
that when you saw from one little angle was like
08:31
this. And this little technique got popular in the
08:34
16th century and the 17th century to disguise
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hidden meanings, where you could flip the image and
08:40
see it from one little point of view like this.
08:43
But these are early incorporations of illusions
08:48
brought to -- sort of high point with Hans
08:51
Holbein's "Ambassadors." And Hans Holbein worked
08:53
for Henry VIII. This was hung on a wall where you
08:56
could walk down from the stair and you can see
09:00
this hidden skull.
09:02
All right, now I'm going to show you some
09:06
designers who work with illusions to give that
09:09
element of surprise. One of my favorites is Scott
09:11
Kim. I worked with Scott to create some illusions
09:14
for TED that I hope you will enjoy. We have one
09:18
here on TED and happiness.
09:23
OK now. Arthur [Ganson] hasn't talked yet, but his is
09:41
going to be a delightful talk and he has some of
09:44
his really fantastic machines outside. And so, we
09:47
-- Scott created this wonderful tribute to Arthur
09:54
Ganson.
09:57
Well, there's analog and digital. Thought that
10:09
was appropriate here.
10:17
And figure goes to ground.
10:23
And for the musicians.
10:38
And of course, since happiness -- we want "joy to the
10:59
world."
11:01
Now, another great designer -- he's very well
11:11
known in Japan -- Shigeo Fukuda. And he just
11:13
builds some fantastic things. This is simply
11:18
amazing. This is a pile of junk that when you view
11:20
it from one particular angle, you see its
11:27
reflection in the mirror as a perfect piano.
11:36
Pianist transforms to violinist.
11:54
This is really wild. This assemblage of forks,
12:07
knives and spoons and various cutlery, welded
12:13
together. It gives a shadow of a motorcycle. You learn
12:16
something in the sort of thing that I do, which
12:29
is there are people out there with a lot of time
12:32
on their hands.
12:34
Ken Knowlton does wonderful composite images, like
12:39
creating Jacques Cousteau out of seashells --
12:45
un-retouched seashells, but just by rearranging
12:47
them. He did Einstein out of dice because, after
12:49
all, Einstein said, "God does not play dice with
12:53
the universe." Bert Herzog out of un-retouched
12:56
keyboards. Will Shortz, crossword puzzle. John
13:01
Cederquist does these wonderful trompe l'oeil
13:06
cabinets.
13:10
Now, I'm going to skip ahead since I'm sort of running
13:12
[behind]. I want to show you quickly what I've
13:14
created, some new type of illusions. I've done
13:17
something with taking the Pixar-type illusions. So
13:22
you see these kids the same size here, running
13:26
down the hall. The two table tops of the same size.
13:30
They're looking out two directions at once. You
13:33
have a larger piece fitting in with a smaller. And
13:37
that's something for you to think about, all
13:44
right? So you see larger pieces fitting in within
13:46
smaller pieces here. Does everyone see that? Which
13:48
is impossible. You can see the two kids are
13:52
looking out simultaneously out of two different
13:57
directions at once. Now can you believe these two
13:59
table tops are the same size and shape? They are.
14:06
So, if you measured them, they would be. And as I say,
14:10
those two figures are identical in size and shape.
14:16
And it's interesting, by doing this in this sort
14:22
of rendered fashion, how much stronger the
14:26
illusions are. Any case, I hope this has brought
14:29
you a little joy and happiness, and if you're
14:31
interested in seeing more cool effects, see me
14:33
outside. I'd be happy to show you lots of things.
14:36

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About the speaker:

Al Seckel - Master of visual illusions
Al Seckel explored how eye tricks can reveal the way the brain processes visual information -- or fails to do so. Among his other accomplishments: He co-created the Darwin Fish.

Why you should listen

Al Seckel took great delight in visual illusions and the brain mechanics that they reveal. The author of many books and articles, he also designed interactive museum exhibits around the world that allow visitors to play with illusions and understand how they work.

A noted lecturer, he was a member of the Edge Foundation, a founder of the Southern California Skeptics, a campaigner against the teaching of creationism in public schools -- and co-creator of the Darwin Fish. Seckel died in 2015. Watch his 2010 talk from TEDxUSC: "[Y]Our Mind's Eye" >>

Note: A previous version of this biography described Seckel as a "cognitive neuroscientist," which was not accurate.

More profile about the speaker
Al Seckel | Speaker | TED.com