Navigating with Models and Maps
2006
It’s no secret that the act of designing is a process of communication
between audience and user. The layout of a
page in a magazine tells a reader of that magazine where to
look, what’s important, where to start reading, and more.
The same goes for the designer of, say, the knobs and buttons
on a car stereo. The designer knows exactly how it
works, since he was involved in the process of designing the
device from the start. Since designers are privy to the inner
workings of a device, or story, or Web page, it’s easy for
them to form a model in their minds to represent those
intricacies. “The stereo can get louder or softer,†thinks its
designer. But without a knob, there is no way its owner
would know this. By placing a knob on the device, the designer
 has exposed a piece of his mental model to the user
through context.
The CHI community likes to talk about mental models
and mental maps using the analogy of how we navigate
through the streets and avenues of the cities we live in and
with which we are familiar. You know where you’re going,
how things work, what the symbols mean, and even to
avoid 5th Avenue because they’re tearing it up again. You
seldom get lost and rarely need more than an address and
cross street to find a new restaurant or shop.
But think about the last time you visited a completely
new city, especially in a foreign country. As you wandered
around the city as a tourist, you probably felt a sense of disorientation,
even though you still knew the basic rules. You
walked on the sidewalk and not in traffic, you stopped at
intersections, you understood that the numbers on the buildings
represented addresses which go up in one direction and
down if you go the other way. Thankfully, your previous
experience with the design of cities applied to this one too.
By applying your mental model of cities to this one, you
made the differences that much easier to negotiate.
But back to the Web. For your design to be successful,
you must match your mental model with the one the user is
progressively building. Again, this is another way of adding
consistency to your Web pages. Your site may have a company
logo in the corner of the page. A user discovers that
by clicking on it, they return to the site’s home page.
They’ve just been given a glimpse into how the system—in
this case your Web site—works. If, a few pages later, the
same user clicks the logo and it doesn’t take them back to
the home page, you’ve chipped away at the user’s model.
When there is a miscommunication between the designer
and the user, things fall apart quickly.
