-
People are remarkable in all sorts of ways, but our attention in short-term memory are limited resources.
-
Fortunately, there’s hope.
-
The representations provided by language, gesture, drawings, and objects help us communicate and reason.
-
And, importantly for design, different representations can facilitate or hinder different thoughts.
-
The insight of today’s lecture is:
-
The ways in which we [inaudible] in the world organize and represent ideas
-
can have a drastic impact on our cognitive abilities, for better and for worse.
-
Things can help us think and you can leverage this as a designer.
-
Let’s start with an example that comes from Don Norman and Jiajie Zhang:
-
It’s a really strange diner, and in this diner the wait staff is not so good.
-
And the three people at the diner ordered oranges but they ended up on the wrong plates.
-
And your job — you can try this at home — is to help sort out which orange belongs on which plate.
-
And so, the way that the Oranges Puzzle works
-
is you need to order the oranges by size: largest to smallest, left to right.
-
Only one orange can be transferred at a time.
-
An orange can only be transferred to a plate on which it’ll be in the largest.
-
And only the largest orange on a plate can be transferred to another plate.
-
And so, I have three oranges here.
-
Our recording got a little bit delayed because somebody ate this little orange
-
so I had to go back to the market and get another one.
-
But we have an orange now and let me show you how this works.
-
So, I’m going to lay this out.
-
I’ve my diner coffee…
-
Here you have the three oranges as delivered by the wait staff.
-
And you can see they’re in the wrong order —
-
The largest one’s in the middle, and the middle one’s over here,
-
and the smallest one, which needs to be over here, is over on this side.
-
And so, to help save these diners,
-
one of the TA’s for the HCI online class, Alex, is going to come and sort this out.
-
>> Oh man, seems very difficult. So I have to only transfer one orange at a time, right?
-
>> One orange at a time.
-
>> And I can only put in to the biggest plate.
-
>> It has to be the largest orange on the plate.
-
>> Okay. So, can I transfer this here?
-
>> No, ’cause then it won’t be the largest orange.
-
>> Okay. So, can I transfer it here?
-
>> You bet!
-
>> Okay. And then can I transfer this one over here?
-
>> Sure!
-
>> And then this one here?
-
>> You got it! Well done!
-
>> Thank you!
-
>> And there’s a couple other diners who’s got similar orders; they all wanted bagels, and…
-
So, their first course is oranges; the second course is going to be bagels.
-
The real bagels puzzle is “Why you can’t get a decent bagel in California?”
-
But the Bagels Puzzle that we have for today is a little bit different:
-
So, we have our largest bagel, medium bagel, smallest bagel.
-
So, the plan is the same, except with the bagels, you have the ability to stack them:
-
You can out a larger bagel on top of a smaller bagel, but not a smaller bagel on top of a larger one.
-
And so, at any point in time, just like the oranges, it needs to be the largest one on the plate.
-
And these are in reverse order, and Alex is going to help us again,
-
rearranging the bagels so that the largest is on the left and the smallest is on the right.
-
>> Cool. So it has to be the largest, right?
-
>> Largest on the left.
-
>> So I can move this one here?
-
>> You got it!
-
>> I can move this one here?
-
>> Yup!
-
>> And I can move this one here?
-
>> Yup! There you go, well done!
-
Now all of our diners are happy — presuming of course, these are New York bagels,
-
which they are not, but that’s close enough for now.
-
So, that’s our bagels game for today.
-
You can try these at home, and what you see
-
is the fact that the bagels represent some of the constraints of the problem in the physical structure
-
makes it much easier to remember the state:
-
You don’t have to remember which of these two bagels is larger and therefore movable
-
because the larger on is on top —
-
you’re not going to move this medium-sized bagel; it’s underneath.
-
And that makes it all a lot easier —
-
when a representation of a problem enforces the constraints and the rules of the problem.
-
And you can think of this a lot of ways, like, when you leave your keys by the door
-
so that right as you walk out the door, you bring your keys with you.
-
That’s a way of structuring the physical world to serve as a reminder
-
and to embed the constraints that you need —to leave with your keys — in the physical space itself.
-
And, as some of you may have realized, you can think of these as being Towers of Hanoi.
-
And what’s interesting thing about this —
-
Towers of Hanoi is the kid’s game where you can move circles between pegs — that look a lot like bagels.
-
And what we’ve done is we’ve turned this Towers of Hanoi game into something where the rules are the same;
-
it’s just the representation has changed.
-
And let’s play a game — we’re going to play a card game now.
-
Two players.
-
Each of you is going to draw a number, one at a time such that you have three numbers that add up to 15.
-
And your draw is without replacement; so, if I’ve picked five, that’s no longer available.
-
For example, if I was able to get four, five, and six,
-
together those add up to fifteen, and that would be a winning hand.
-
So, let’s say for example, I pick five for starters, and the other player picks six.
-
So I pick three, and the other player picks two, and then I pick seven.
-
That would be a winning hand.
-
And, this is hard enough for one player. As you can see, it’s even harder to try and play both sides.
-
So we can make this a little bit easier.
-
So let’s say, instead of having it be numbers imaginary in our head,
-
we’ll do the same thing, but with playing cards.
-
And so I’m going to be able to have the numbers one through nine here — or ace through nine.
-
So, here we have the playing cards, ace through nine.
-
And again, two players, and this time we can lay ’em out in the table.
-
So I’ll lay these out so I can see ’em.
-
And again, start out by picking five, And the other player might pick six, and so I’ll go three.
-
And at this point — especially [as] the other player can see my numbers —
-
they’ll know that seven is what I want next, so they’re going to go seven,
-
and I’ll go two to prevent their 15.
-
And — alright, now they’re going to head off in another [tactic]…
-
So… maybe we can do…
-
Let’s try this: one. I haven’t thought it through, but that might help.
-
And at this point, I start to wonder whether this is going to work.
-
So, take — I’m not really playing here — but I’ll take nine — 12, 14… almost…
-
and it’s kind of nothing you can do at this point, and so… No dice!
-
A lot easier, especially early on, but still somewhat challenging.
-
Let’s play another game. We’ll pick an easier this time. How about Tic Tac Toe?
-
So, this is pretty easy. I think many of you know this game: So we can do x’s and o’s.
-
Somebody can go x, and somebody can go o. We can do x, and o, and x, and o, and x wins.
-
That game is a whole lot faster than either of the two cards we play,
-
but what might shock you is that these two games are isomorphs.
-
So I can fill in the numbers one through nine and have them be exactly equivalent to our card game.
-
Any row or diagonal that adds to fifteen also produces a winning game in Tic Tac Toe.
-
So for example, I can pick this right column, that’s 15, 15, all the way through.
-
And what we see from this is that the way that you represent the problem —
-
drawing numbers in our head, cards on the table or numbers in a grid —
-
has drastic influences on our ability to solve that problem fluently and to see alternate solutions
-
and to be able to coordinate our action with another person.
-
And this is why Herb Simon, the famous artificial intelligence and cognitive science researcher,
-
writes that “Solving a problem simply means representing it so as to make the solution transparent.”
-
For example, if you think about proofs in mathematics,
-
what’s true at the end of the proof is also true at the beginning.
-
The only thing that’s changed along the way
-
is that the fact that the proof is indeed true has been rendered clear to the reader.
-
Why were the Oranges Puzzle and the number selection game so difficult?
-
It’s because both of them tax our working memory —
-
we had to keep in mind what moves are possible, what numbers we held,
-
what the other person was thinking and maybe doing — and that was a lot to keep in mind all at once.
-
Human beings are incredible in all sorts of ways; working memory is not one of them.
-
And one of the most important things that we can do with user interfaces
-
by embedding the constraints of the problem in the user interface itself
-
is to offload working memory so that those limited resources become available for other people.
-
You may have heard the famous “seven plus or minus two” as a limit of working memory,
-
that we can keep seven plus or minus two things available at any point in time.
-
And that’s not exactly true — the real story is a bit more complicated —
-
but if you want to have a rule of thumb to work with as a designer,
-
I suggest two plus or minus two —
-
that basically don’t require users to keep anything in mind that you can possibly put on the screen.
-
So far the examples that we’ve looked at — oranges, bagels, cards, Tic Tac Toe —
-
are kind of toy problems.
-
And, you know, they may make for some good entertainment at a dinner party
-
but it’s not real-world stuff.
-
They demonstrate, however, principles of the power of distributing cognition —
-
That absolutely have real world impact.
-
One great example of this is that task management system Getting Things Done.
-
It’s very much designed in the principles of distributing cognition in mind.
-
So, for example, one of the rules of the Getting Things Done system is that
-
whenever something comes to your mind that you need to do,
-
the first thing you do is write it down — somewhere, anywhere.
-
And the reason for that is that if you have something in mind
-
that needs to be completed and you haven’t written it down yet,
-
you’re spending a lot of cycles of working memory, remembering to “I need to do my laundry”,
-
the same thing — “I need to do my laundry”, “I need to do my laundry”…
-
and that’s chewing up resources that could be better deployed elsewhere.
-
“Write it down” gets it out of your mind, and you can move on.
-
One of the words that people toss around all the time in terms of effective user interfaces
-
is that “this user interface is ‘natural.’”
-
And when we say that, we mean a couple of different things,
-
but one of the things that we mean [that] we can see in our example of the oranges and the bagels
-
[is] that the bagels, as a task, is more natural — because the properties of the representation —
-
bagels can stack — matches the properties of the thing that’s being represented.
-
One of my user interfaces for this perspective is the Proteus indigestible pill.
-
This is a pill that, when you swallow it,
-
it sends out a little signal so that your phone — or the Internet — knows that you’ve taken this pill.
-
And the ability of keeping track of whether you’ve taken the pill or not automatically, by virtue of taking the pill,
-
is a really natural user interface —
-
the ingestion act serves both to take the pill and to mark that you have done so.
-
There’s another example of a really natural interaction in this system which is
-
that, in addition to the pill, there’s a transmitter that you need to stick to your body.
-
And the transmitter has a limited battery life.
-
So, how do you turn the transmitter on?
-
It’s a Band-aid-like system, and the way that you turn on the transmitter is
-
you peel back the Band-aid bandage, and that turns it on.
-
And so, again, that action that you need to do to stick it on yourself
-
is exactly the same action that you use to turn the [transmitter] on.
-
And so by integrating the necessary step with the step that’s easy to forget,
-
you don’t forget the step anymore.
-
So let’s bring this back to normal user interfaces.
-
Here’s an example of the Print dialog on a Macintosh.
-
And one of the things that you can see here is that there’s a world-in-miniature strategy in this Print dialog box.
-
So, if I want to look at the Stanford Academic Calendar, I can print that here.
-
And, what we’re going to look at is:
-
here’s our world in miniature, where we see the entire legal-sized page shown inside the dialog box.
-
And one of the things that that makes clear
-
is that I’m not going to be able to fit the top and the bottom of the page on a letter-sized page
-
because a letter sized page is three inches shorter than a legal page,
-
and so consequently, you know, it’s probably not something I want to do.
-
And, one of the things that I like about this is that by showing you the world in miniature,
-
the challenges of working that you’ve got to decide here become much clearer.
-
Here’s another example; this is from Microsoft Word, and what we can see here is —
-
I’m again about to print this, and the dialog box that I get from word says
-
“A footer of section 1 is set outside the printable area of the page. Do you want to continue?”
-
And I can click Yes or I can click No.
-
Now, in order to answer this problem, I need to know:
-
is it just that the bounding box of the footer is outside what the printer can print and so it’s irrelevant
-
or is there actually content that I need that won’t be printed?
-
None of that is available from this dialog box,
-
and so, unlike the previous print dialog
-
where we saw the world in miniature and could see what was being cut off,
-
here we have no idea what’s being cut off,
-
and consequently, this is a much less effective user interface.
-
And that’s the end of part one.