The UX Group recently had a session in which fellow Grad Student Amy Gill (who was wonderful!) spoke about her research into the Think Aloud method and how we can use it as practitioners. Perhaps the first thing that came to mind was “isn’t it just a usability test method?” but really it’s a psychology method that we’ve taken and applied to our field. We often forget the origin of the methods we use, but the origins can provide us with a helpful refresher on when and how we should be using these methods.

The Think Aloud method was originally developed for use in Psychology to – surprise! – learn about thought patterns. Originated in 1980 by Simon and Ericsson [1], the theory was a new way of thinking about psychology, recognizing that thought patterns were important and that behaviourism wasn’t necessarily the right path to truly understanding the human brain (ask me about behaviourism another time…). In any case, they proposed that verbal reports can be taken as valid data as long as they are reports of a certain level. Level 1 reports require the least amount of processing – information that is already stored in the brain as verbal code is simply vocalized. Level 2 reports require some processing – information stored in a different format (visual, spatial) is recoded and articulated as verbal code. Level 3 reports require generation of new material that does not already exist in the brain, such as explanations of actions. Of these three levels, only the first two can really be assumed to be valid reports of brain thought patterns thought to interfere to a limited and negligible degree.

What does this mean for usability?  Amy explained that perhaps the most distilled point that we can get from the psychological origin of our method is that we shouldn’t ask “Why?”. We should ask it afterwards if we want to really delve into the whys of our participants actions, but not during a Think Aloud task. We want the users to give us an honest and unfiltered stream of consciousness to better understand the mental models they are forming as they use our interfaces. We don’t want them to start analyzing what they’re doing, or giving us the first answer that seems plausible, or telling us what we want to hear.

There was a lot of confusion and some claims of “I ask Why, and it’s worked fine!”, but I think we should keep in mind that Think Aloud is really a method aimed at collecting a specific kind of data: mental models and thought processes. When we want to make sure that our understanding and view of the interface matches up with the user’s, we should use Think Aloud. When we want to see where a user becomes confused, or when the mental processing they have to accomplish in their head becomes overwhelming, we should use Think Aloud. However, when we want to gain an indepth understanding of how and why a user would use this interface, and how well it meets their specific process needs, we might not want to use Think Aloud – maybe consider contextual inquiry or one of the many other useful tools in a usability practitioner’s toolbox.

In either case, Amy’s talk made me think about two main lessons that often get lost in the day-to-day: 1) understanding the history and roots of a method can clarify how to really use it, and 2) pick the data you want, then the method – not vice-versa!

[1] Ericsson, K.A. and H.A. Simon, Verbal reports as data. Psychological Review, 1980. 87(3): p. 215-251.