Original subtitles

- Hi. I'm William Lidwell and this is

Universal Principles of Design.

In this movie, Desire Lines:

Exploring the road most traveled.

There is a famous, though probably apocryphal

story about an architect who,

after completing a new building

on a college campus

decided to leave the courtyard and

other grassy areas around the building

without sidewalks.

The idea was to let students and faculty

use the building for a year

and let their use form trails in the grass.

Then lay the sidewalks on top of those paths.

This story may be apocryphal,

but it sure is smart apocryphal.

It's smart because it illustrates a way

to find out how people in aggregate

actually use something.

In this case a landscape which can then

be used as a blueprint for design.

It's like a statistical use graph

drawn on to nature.

It's beautiful.

Now consider the all too common alternative.

How many times have you seen trails in the grass

that break off of a paved walkway?

You know, trails like this.

Or this.

Or this.

In these cases, designers try to prescribe

how space should be used by

putting in sidewalks.

And people simply refuse to follow the prescription.

This is the peril of designer-centered design.

A designer knows best way of thinking.

All too often designers don't know best.

Letting the trails form first

and then putting in the sidewalks

is an example of user-centered design philosophy.

Develop a deep understanding of how

people will interact or use a thing

and then let that understanding

inform and guide the design.

This example is so compelling,

architects and designers have started

adopting the approach in design.

They've even given these trails a name.

Desire lines, or desire paths.

There's even a desire path reddit

where people post examples they run across.

It's become quite a thing.

So what are desire lines more broadly?

Desire lines are traces of use or wear

that indicate preferred methods of interaction.

They generally refer to worn paths

where people walk,

but can be applied to any signs or traces

left by user activity.

On floors.

Objects.

And even websites, where heat maps

and cookie trails are used to track user activity.

For example, this picture demonstrates

the different keyboard wear patterns

by two different types of computer users.

When a gamer, you can tell because

the most commonly used directional keys

in video games are ADWS.

And the other, a programmer.

Programming languages like C and Javascript

make heavy use of semicolons and

quotation marks.

Here's another.

It tells us that people try to put their car key

where they expect the ignition to be without looking.

Interesting, if you're designing such things.

One more.

I was in a design meeting at a building

and a discussion came up about their doors.

The door mechanisms kept failing.

The group discussion focused on

the poor quality of the door mechanisms,

other possible manufacturers they could

switch to, and so on.

I brought up the fact that

the failure of the mechanisms was

actually an indication that the doors

were poorly designed.

It was not clear whether they

were push or pull.

And the failures were the result

of people crashing into them.

People using the doors were telling us

about the problem through desire lines,

which, in this case were the broken door mechanisms.

The team just needed to

learn how to listen.

There is perhaps no more reliable indication

of interaction and use than desire lines.

You can ask people how they will use something,

but their responses are never reliable.

You can observe them,

but often observing them alters their behavior.

They know they're being watched or videoed.

By contrast, desire lines are a non-invasive,

unbiased and statistical measure

of how people actually use things.

From a user-centered design perspective,

they are like blueprint sketches hinting

at the perfect design.

So whether you use desire lines

to conduct better user research,

improve usability of your physical

and digital products,

or to plot the perfect path

through a park or courtyard, remember

always explore the road most traveled.

There is much to be learned there.