Did they see it?

We’re often asked whether participants in a study notice certain design elements—icons, labels, ads, a component of a company logo, or a product function—in a user interface.

For a participant to notice these elements involves both seeing and perceiving, so this simple question can be easier to ask than to answer.

Seeing and perceiving are of course different things. Participants can have design elements in their visual field without consciously recognizing their relevance or meaning.

Understanding whether participants notice things, then, requires multiple approaches. Here are three approaches we use; each has its strengths and weaknesses.

Ask them

The most obvious way to assess perception is to ask participants. The major drawback here is that people have a tendency to remember things they didn’t see. This is the same problem that plagues eye-witness testimony. Eye-witnesses can see things that didn’t happen or people and things who weren’t there.

The mere act of asking participants whether they recall an image, feature, label, or function primes them to say they remember it.

One way to offset this problem in a research setting is to include “distractor” options. If you want to know whether participants saw a “favorites” icon, for example, ask about it and ask about icons that didn’t exist so you have some false memory reference point.

Watch their eyes

By “watch their eyes,” I don’t mean staring into your participants’ eyes like some sort of crazed hypnotist. I mean, of course, to track their eyes using eye-tracking technology. Eye-trackers will tell you at least whether the design element was encountered by your participants’ eye gaze.

For example, the FedEx logo is one of a number of logos that has a subtle image—an arrow between the E and the X—hidden in plain sight. Once you see it you’ll always see it. We asked a participant to examine the UPS and FedEx logos for a few seconds (notice how we added at least one distractor stimulus). We then asked her whether she recalled any shapes within either logo. She recalled only a square and a circle in the FedEx logo.

We then told her to examine the logo again and look for an arrow.

 Gaze path before perceiving the arrow  Gaze path after we told her to find the arrow.

Eye gaze is necessary but not sufficient to establish perception. Just because the eyes see an element doesn’t mean the brain perceives it. In the example above, the gaze path didn’t encounter our area of interest, the arrow; instead it danced elsewhere across the logo. After revealing the shape, the participant’s gaze path intersects repeatedly with the arrow, creating the necessary condition for perception.

Even with eye tracking, when we want to know whether a participant notices something, we also follow up by asking participants whether they recall seeing the element (mixing 1 and 2).

Observe them

A higher-touch, often essential way to understand whether people see and perceive elements is to observe what they do and how they react. This is the fundamental principal behind usability testing. Usability testing tells you whether participants notice a feature or function in an interface and whether they understand it well enough to use it.

In usability testing, we don’t want to lead participants down a predetermined path by putting words in their mouths or ideas in their heads. Instead we use this method, often while having participants think aloud to uncover the mental model.

For example, to assess a “favorites” feature on a mobile application for viewing videos, you can do a number of things:

  1. Ask participants what the favorites feature does (approach #1).
  2. Track participants’ eyes to see whether their gaze even cross the favorites area (approach #2).
  3. Ask participants to save a TV show for later viewing and see whether they successfully add a series using the favorites feature (approach #3).


Noticing an element is one thing. You want to know not only whether participants notice the element but also whether they understand it and can use it. Measuring perception and getting findings that you can trust requires a mix of approaches:

  • recalling (with distractors)
  • eye tracking (if appropriate)
  • direct observation of behavior (as in usability testing)

Now did they see it ?