Jared M. Spool

When conducting usability tests, you can infer lots of things about
what you see and hear.  When we see that users consistently skip
over banner advertising, even if it contains interesting content, we
can infer that they don't pay any attention to the ads.  But do they
actually see it?

For the past year, we've been watching users with the assistance of
an ASL Eye-Tracker -- a device that lets us determine, to the pixel,
exactly where the user is gazing when looking at the screen.  The
result: we've confirmed many of the inferences we've had.  But,
we've also been surprised at some of what we've found. In the feature
article below, we share some of what we've seen in our recent
testing.

As always, if you receive duplicate messages from us, just 
forward both back to me and I'll research the problem. If you have 
any questions or comments, please feel free to drop me a note at
jspool@uie.com.

Jared

_______________
Feature: Testing Web Sites with Eye-Tracking

Thanks to some recent usability studies we conducted using an
eye-tracking system, we now have real evidence of where users
actually look when they view a web page. 

It's clear that users quickly learn to look where they expect to
find content. They also quickly learn to avoid areas where they don't
see -- or expect -- what they're looking for, including banner ads
and parts of the page outside the central area. 

> Where Did Users Look?

Our client wanted to know how much attention users would pay to
several areas of a prototype web page, and thus to the content of
each area. With the eye tracker, we monitored how much time users
looked at each area. 

To determine where users looked on the prototype web page, we
tracked their eye movements within six areas of the design grid and
navigation pages. They were labeled the Center Area, the Left Panel,
the Right Column, the Browser Button Bar, the Search Engine Block,
and the Study Area. 

We asked users to look for specific information on the site. When
deciding which link to click, users typically looked first in the
center area, then in the left panel, then in the right column. Users
spent an average of 11 seconds on each of the pages we tested. Our
users were more likely to investigate areas outside the Center Area
when they spent more time searching for the correct link, or when
they visited the page for the second or third time in a task.

> Scan Patterns Were Similar

All the users spent the same proportion of time looking at each area.
This similarity of behavior surprised us. We think it means that they
all applied similar criteria in deciding on the relative importance
of the tested areas (i.e., the likelihood each area would contain the
link or information they wanted).

New and experienced web users scanned essentially the same way. 
At first, the new user scanned pages from left to right, as if 
reading a book. But he quickly changed to the center-left-right 
sequence.

The new user needed only two or three page visits to learn where to
find the "good stuff" and how to avoid material that was less
interesting to him. He looked at the browser controls more than the
experienced users did, but his strategy was otherwise unremarkable.
We had only a single new-to-the-web user, but this is an interesting
pattern to watch for.

Because these users so quickly adopted the center-left-right
strategy, we believe the experienced users, who used it immediately,
had learned the behavior through their earlier visits to other web
sites. This suggests that designers may not need to design pages
differently for new web users, but we'd need more tests to confirm
this.

> Users Don't Go to the Bottom

Users rarely looked at what we called the Study Area just above the
browser's status line. Users often found what they wanted before
getting to this area. Interestingly, if they wanted to see
information from this area, they scrolled to bring it higher on the
screen rather than looking at the bottom. 

Some users failed to find content that began within this area. For
these users, the "fold" was 2/3 of the way down the first screen,
not at the bottom. Users may not look where they don't expect useful
material. 

> New Scans for Some Changes

We tested several variations of the site's prototype page layout to
see if they'd alter user behavior. When the designers changed the
proportions and content of the three main areas only slightly, users
kept the same scan pattern. Horizontal and vertical grid changes of
6-to-12 pixels (1/8 inch at the resolution we tested) had no
apparent effect on users. 

On the other hand, all users immediately detected a change that
narrowed the left column about 30 pixels (1/3 inch) and used a
heavier font. Most users scanned this changed area as soon as it
appeared and read the content.

Users apparently will reevaluate their scan strategy when they detect
a design change of this magnitude. This argues against the design
strategy of using a consistent grid on all pages. It may cause users
to miss content of interest.

Users seem to notice changes somewhere between 12 and 30 pixels,
but we didn't test for this, so we don't know how big the change must 
be before users notice. 

> What Attracted Users

Using direct observations as well as videotapes of user behavior, we
found that: 

    Bright colors and animation attract users' eyes. This is not a new
    finding, but it is interesting to actually see it happen. The gaze
    flicks to the animation, dwells for an instant, and then returns 
    to content.

    Eye gaze often stopped at the borders around ads (the bottom of
    ads at the top of the page and the top of those near the bottom).
    To users, these lines apparently indicate content that is
    unimportant to their task.

> The Role of Peripheral Vision

The eye tracker tells us where the users direct their central vision,
the part of the visual field that can discriminate fine detail. But
peripheral vision clearly plays a role. We can't measure how much,
but we must account for peripheral vision in interpreting what users
see. For example:

    Users rarely looked directly at the scrollbar; their gaze peaked
    considerably to the left of it. This shows that they don't look at
    the scrollbar, even when using it. Peripheral vision obviously
    helped.

    Ads apparently attracted users only when they related to the
    current task (even if the content interested users but was
    irrelevant to the task). For instance, a lover of old automobiles
    was not attracted to an ad featuring a picture of an antique car.
    These observations are further evidence that peripheral vision
    plays a role: users somehow determined if an ad interested them
    before they looked directly at it.

>  Want to know more about the cool stuff we've learned regarding web
site usability?

Come to Web Sites That Work; Designing with Your Eyes Open, in San
Francisco, CA on July 12-13, 1999. You can get detailed course
information by sending mail to WEBCOURSE@UIE.COM with the words 
SEND INFO in the subject field, or by visiting our web site at
http://www.uie.com.