Basically, you ask the test participant to continuously verbalize his or her thoughts and keep up a running monologue as they use the computer. Easy. And yet. People can do it, but it’s a bit unnatural to just sit and talk and talk and talk — having to say anything that comes to mind without it being part of a conversation. One of the main things we teach in our Usability Testing course is how to facilitate a test and prod the user to keep talking. (Use neutral prompts that don’t bias users’ behavior — important but not my topic today.)
Most users need some prompting from time to time, but first you’ve got to get them to start talking in the first place. A great way to do so is by showing the test user a short video of somebody else thinking aloud. Demonstrating something by a concrete example gets the point across better than most abstract explanations.
What to Put in the Demo Video
Some criteria for a demonstration video of thinking aloud:
The video should be short, because you have a tight time budget in any research study and want to spend almost all of it observing the user’s actual behavior and very little time on administrative overhead. 1 minute is a good video length. (We tried a 2-minute video, but it was too long and didn’t add any real value over a 1-minute video.)
It should show a different user interface than the one you will be testing in the study. Otherwise you’ll bias the user. Some people like to do the demo with a design that’s not even a computer: for example, how to refill a stapler. I prefer showing a screen-based UI, because then we can also demo the kinds of comments we’re looking for.
In order not to intimidate the study participant, we don’t include a picture-in-picture of the person doing the demo. While we definitely should disclose to study participants if they’re being video recorded, we don’t want to belabor the point and make them overly conscious of having their image appear in the study recording.
The person recording the demo should obviously be an outspoken “good participant” and keep talking throughout the demo. It’s worth rehearsing your demo think-aloud a few times before recording it. For privacy reasons, don’t use a real user; use your own staff to record the demo. Plus, use somebody who speaks with a clean, easily understood, audible voice.
Demonstrate key points you want to learn from a usability study, such as
This is what I expect will happen if I click here
This page or resulting action is not what I expected
This text/instruction/image/etc. is confusing
This is easy/difficult
This is what I think this text/instruction/image/etc. means
I like/dislike this
This is not what I need — I need XX instead
Don’t bias the user by focusing on a specific point you want feedback on. Say you’re interested in the style of images on your site. Sure, have your demo include a comment about some image, but don’t limit the demo to discussing the images or diving deep into an image analysis. If you prime users to think in a certain way, they’ll do so for the duration of your study, but your findings won’t represent real use.
Don’t be funny. Even though it’s tempting to joke and produce a lighthearted video, stay serious because you want users to take the test tasks seriously and perform them as if they were visiting the site for real.
Sample Thinking Aloud Demo Video
Here is an example of a demonstration video that illustrates what it means to think aloud during a usability study. Feel free to show our video to your own study participants if you don’t want to make your own.