What heatmaps hide: Embracing human complexity through individual gaze data

Human beings are fantastic, complicated, amazing biological machines. Every person brings their own mix of experience, perspective, and traits that make them unique. While this natural diversity highlights the beauty and complexity of human life, sometimes the tools we use to aggregate human behavior can lead to sweeping generalizations, missing out on outliers and granularity in our findings.

One such tool is the eye tracking heatmap, which is used to visualize where one or multiple people look when they view and interact with a product, environment, design or media for example. By combining the gaze data of many participants, these heatmaps show areas of high visual attention, revealing ‘hot spots’ and patterns in how people interact with what they see. However, while eye tracking heatmaps in the right context are very powerful giving us valuable insights, they also have a big downside: they hide the individual characteristics of each participant. 

The ups and downs of eye tracking heatmaps 

Eye tracking technology has changed the way we understand visual behavior across all aspects of research from academia to elite sports, from product design to
shopper research and everything in-between. By tracking eye movements, we have enabled researchers and designers to see through the eyes of their participants, spotting focal points and areas of interest, regions that are missed and where they dwell or revisit the most. Heatmaps, which combine this data, are popular because they give a clear and easy-to-understand visualization of where attention is focused — with a simple color coded mapping to bring the data to life. 

But the process of combining data is naturally reductive. When data from many individuals is merged into a single visual representation, the unique paths and patterns of each participant sometimes get lost. What we get is a general view that, while helpful in many contexts, lacks the fine details that make each person's experience unique. 

When individual differences matter 

Human behavior and how people see, interact and work with their environment varies wildly and, in many fields, we are looking more to identify the individuals' actions as opposed to group alignment. Fields such as training and skills transfer, professional performance, sports and driving assessment are obvious examples but this also extends to other qualitative fields of research such a product or medical device testing, being able to accurately measure and improve performance in these fields all hinge on us understanding that person's capability and performance.  

Eye movements and attention are influenced by many factors, including their past experiences, task at hand, familiarity with their environment, thought processes, and even their mood at the time, so when assessing a worker on a production line we truly need to understand that person, in that moment, on that task. By only looking at combined data, we risk missing these important individual differences and also the sequence and timeline of interaction. 

If we continue to use the example of manufacturing and look at an individual heat map of the worker going through their standardized work procedure, we would see various ‘hot spots’ around their workspace, maybe around tools or components they used. What we don’t see if the sequence of interaction, if they were looking at the right place at the right time in their work instruction and if those interactions were a single or multiple visits — basically we are missing the actual ‘what and when’ and additionally cannot check compliance to what we expect them to do to aid with training, skills improvement and process optimization.  

Our powerful eye tracking analysis software, Tobii Pro Lab, gives us an array of tools, metrics and visualizations to allow us to work with individual and group data, and is a fantastically powerful research tool.

However, many use cases require a simpler tool for non-experts. That’s why we developed the Tobii Glasses X and Glasses Explore solution — to help more people quickly gain qualitative insights by seeing through the eyes of their workforce, athletes, customers, or consumers.

To enable rapid and non-intrusive use, you simply put on Tobii Glasses X, press start recording in the mobile app, and let the participant complete their tasks naturally. Then the data is automatically sent to the cloud and is ready for review in minutes. You might then choose to appraise this alongside an example of best practices, perform pre and post training comparisons, record tasks for audit purposes or simply understand why someone is really good at what they do so you can share their knowledge and experience. When you identify individual potential for performance improvement, the platform allows you to rapidly share this with the participant or colleagues to review.  

Looking beyond the average 

In conclusion, every human being is a unique part of the human mosaic. While eye tracking heatmaps offer a powerful way to visualize collective attention and are ideally suited for many  studies into visual behavior and attention, sometimes what you really need to do is simply look through the eyes of the individual and how they compare to what you want or expect them to do — and for that you need Tobii Glasses X and Glasses Explore!