
Miller’s Law – A Rule in Product Design and Life Management - pdevine
https://blog.prototypr.io/the-most-important-rule-in-ux-design-that-everyone-breaks-1c1cb188931
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iambateman
You know how people say: “on a scale of 1-10”?

I’ve used the principle of Millers law to start asking people to measure on a
scale of 1-7.

Universally, people balk at the scale. But I explain to them that most people
can’t tell the difference between 2 and 3 on a ten point scale. If you can’t
articulate a difference, there’s no use in the measurement.

Seven is great because you get more than the simplicity of 1-5. So... 1 - the
worst 2 - bad 3 - below avg 4 - average 5 - above average 6 - good 7 - the
best.

And don’t even THINK about responding with “5.5”. ;)

~~~
JasonCEC
There is actually a whole theory around this, and has lots of implications for
the designs of hedonic and sensory scales.

I work on modeling human sensory perception and preference of food and
beverage products, and have had to design scales that work as a true "metric";

Most scales suffer from 3 primary problems:

1) avoidance of the endpoints

2) tendency towards the mean

3) minimum information gain

For example; on a 10 point scale, very few (> .5% of respondents) will mark a
1 or 10 (this is problem 1). In addition, 5's are over represented VS the
expected amount of 4's and 6's (problem 2).

These problems together reduce the amount of information inferable from the
collected data. There is a number of ways to measure this, including
information theory (think of the avoidence of the end points and tendency
towards the mean as a lossy compression algorithm for the true signal) or as a
sampling of an unrepresentative population to infer the posterior
distribution.

A 100 point scale has the same problems as above, and in addition suffers from
a lack of consistency (reproducibility) - respondents are likely to give a
product a different score (say a 92 and 94) when asked about the same product
multiple times. This will frequently lead to non-parametric rank reversals,
which 1) prove that a 100 point scale is not a "metric" and 2) show that the
amount of information is further reduced at higher optionality.

Thus - the discrete scales that work best are:

A) 1 - 7

B) 1 - 13

as they both do not suffer from avoidance of the end points, both have no
selectable mid-point (forcing respondents to choose a point above or below the
median), and are highly replicable (very few respondents will switch rank
orders).

~~~
kurthr
I must be missing something... why isn't 4 a midpoint of 1-7 and 6 a midpoint
of 1-13? I'd think you would want an even number of points to prevent over-
selection (like 0-7 or 1-8).

~~~
JasonCEC
The psychological effect is "tendency towards the mean", and in this case, the
mid-point isn't the mean.

Forcing individuals to choose a score above or below the mean yields a better
sampling of the true distribution in this case.

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agf
What? 1+2+3+4+5+6+7 = 28. 28 / 7 = 4. So 4 is both the midpoint and the mean?

~~~
tiglionabbit
Perhaps people don't differentiate between 1-7 and 0-7 and assume that 3.5 is
always going to be the midpoint?

~~~
JasonCEC
That is correct.

~~~
euyyn
So when they pick 4 on a 1-7 scale, it's not neutral but good, because it's
above 3.5?

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aragorn2
Off topic: I got all 20. What you do is invent a story in pictures.

A cat was playing with a ball under the tree. An apple fell from tree on cats
head. The cat squared around the apple and ran inside the house through a
small door into her box. King dad drove in his car, took out huge hammer from
the trunk and hit the box of milk. Milk sprayed all over the house and inside
the fish tank. Fish got restless and caused a cross bow from the wall to fire
an arrow through the book that was all taped over. Mom in her red shoes came
and took the key under the flower.

~~~
rasengan0
I forgot my pimping king with thor hammer was riding in a car so 19/20 for me.
I wonder when Miller's law is gamed with this narrative technique how
information design is tailored to this long tail of users. Story as the new
UI.

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k2xl
Tangential, but I was able to recite all the words, but only because memorized
them in a nonsensical, but easier to remember story. I like the exercise
because it forces me to be creative.

The CAT looked at me eating an APPLE, I threw a BALL outside to see if it
would chase it instead it climbed a TREE...

~~~
smichel17
Me, too. Instead of having to remember all 20 words, I just had to remember a
few stories: the cat eating an apple on a ball in a tree, the square face
whose house is a boxcar, etc.

~~~
dghf
How many stories? If you had three or so words per story, that would give you
about seven stories, which fits the notion of 7 +/\- 2 "chunks" of
information.

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rossdavidh
I love how they end with a call to reduce your levels of electronic
distraction, then have a list of different social networks you can contact
them at.

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lalaithion
Related to the idea of chunking, I remembered 15 words easily, using a clever
technique that I read about a few years ago. Instead of trying to remember
each word individually, I remembered scenes. This enabled me to remember more
than 7 words, because the chunks no longer were words, but were combinations
of words.

For example, for the words "king" and "hammer", I imagined a king hammer
ruling over his subjects. For "milk" and "fish", I imagined a fish with
udders. They're silly, but they work.

~~~
amelius
But how do you free working memory when you're done?

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agumonkey
I use my hp48 every so often. The UX is primitive, 5 generic keys, slow
refresh lcd. But the RPL (lisp/forth) system has only a few bits of builtin
constructs, which means you'll have maybe 3 level deep worst case. Most things
are below the 7 figure. It's smooth as f. With just a bit of upgrade I
wouldn't mind programming on this at all.

More and more I believe that ignorance thus space exploration and Miller's
"level 1" cache has a huge role in our enjoyment of things.

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gilbetron
A psych professor claimed, years ago, that the number is actually 5 +/\- 2,
but I can't remember his argument. Something about including error of
measurement from the experiments, maybe? Regardless, he said it is why 7 phone
# digits is often difficult for some people, because it is on the high end of
what most people can remember.

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catnaroek
I managed to remember the first 18 elements of the list.

On a more relevant note, it's easier to remember a large number of things when
they're related to each other in meaningful ways. So the results of this
little memory test aren't very good predictors of your ability to remember
things in a real-world setting.

~~~
mjrpes
Worth pointing out how great (and easy to learn and master) a mnemonic device
it is to create a story from the list...

The skinny cat with an apple on it's head ran after the ball that led it to
the tree with square leaves. Each leaf was actually a picture and if you
looked closer you could see a head (of a fat cat) in the picture. You zoom in
and the picture becomes a movie and you see the fat cat walk up to a house and
open the door... etc etc

The more absurd the image you create the easier it is to remember. You also
have much better long term memory. It's been half an hour since I memorized
the list and I've drawn my attention to 5 other HN posts, but here I am able
to recite the list 100% accurately and without hesistation...

Cat apple ball tree square head house door box car king hammer milk fish book
tape arrow flowers key shoe

This is nothing against Miller's Law though... as who goes about creating
visual stories to memorize user interfaces :)

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phkahler
What does memory have to do with how many things are on screen at one time? Do
UI elements get turned into a memorized list or something? But longer term you
can store longer lists. I'm not sure how this limited short term memory
phenomenon relates to UI?

~~~
brianpan
Seven plus or minus two refers to _working_ memory. When you encounter say a
navigation menu with 10+ unstructured items, it becomes impossible to consider
all the options at once.

~~~
phkahler
But when you look at a menu, you know what you're looking for so it's a matter
of identifying one thing. Aside from convenience I don't think the length of a
menu matters much.

~~~
rpedela
The point is when you don't know what you are looking for exactly. The Abobe
products are a good example of this. I don't use Photoshop often so I forget
where stuff is. Having a lot of menus and each menu having a large number of
options makes it difficult for a novice user (like me) to find the resize
image dialog, for example. To be fair, Photoshop is designed for experts and
expert users will learn an interface no matter how crappy it is so it isn't a
big deal in this case. But the endless options and menus do make it harder for
novice users.

If the menus and options were grouped in way that is in line with human
psychology, it would be easier for novice users to find that one option. I
know the Office ribbon gets flack on HN but Miller's Law is one of the big
reasons for the Office ribbon and how it is designed which makes it a lot
easier for novice and intermediate users to find that one option in Office.

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baxtr
Miller’s law says that people can remember 7+/-2 things at a time. I think
that’s why people usually like structured lists much better than a
unstructured, unsorted laundry list.

~~~
user5994461
People can remember only 4 things. The few who can remember more are the
exception.

That would be a much better goal for product design. You don't want designers
to pack things by 7 or 9. It's too many.

~~~
isostatic
I tend to remember 3 things when it comes to things like shopping or tasks.
Add a fourth and I usually end up getting something wrong or forgetting it.

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elysian_eunoia
Similar to the _story method_ of memorization mentioned, using the _Method of
Loci_ makes it easy to memorize all twenty.

[https://en.wikipedia.org/wiki/Method_of_loci](https://en.wikipedia.org/wiki/Method_of_loci)

[https://www.ted.com/talks/joshua_foer_feats_of_memory_anyone...](https://www.ted.com/talks/joshua_foer_feats_of_memory_anyone_can_do)

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joshuaheard
This is why phone numbers are 7 digits long: xxx-xxxx. Then, add another
"chunk" for the area code: (xxx) xxx-xxxx.

~~~
isostatic
Phone numbers are 11 digits long, usually split into 5 and 6, but sometimes
4/7 or 3/8, and even 6/5 and 7/4.

Not that anyone remembers phone numbers nowadays.

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josephby
Hacker News desperately needs a "Saved You a Click" feature.

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friedButter
I think 5-9 words is much more than 7 bits of information...

~~~
BoppreH
Not sure why you were downvoted.

The comment below mine, about "bit" being used as "piece", was my first
thought too. But then the author contrasts with a quote using the actual
entropy definition of a bit.

And chunking doesn't work as an explanation either, even with Huffman
encoding, unless half of all words you ever use are "cat".

Note that even if the word was used incorrectly, it makes no difference on the
author's argument.

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timthelion
Isn't there a law of UX that the viewport should be large enough for the user
to see the article's text? I can see like half a paragraph between the top
stuff and the bottom stuff.

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qrbLPHiKpiux
Jack of all trades. Master of none.

