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How does Eye Tracking Work? A Complete Guide

eye tracking

How does Eye Tracking Work? A Complete Guide

Have you ever wondered why people have white parts in their eyes?

Probably not.

However, when you think about it: It’s weird. Humans are the only primates whose eyes are not fully dark. Even the anthropoid ape, which is very close to us in terms of evolution, does not have white parts. Why do our eyes deviate from the eyes of our fellow primates?


This can be explained by the unique collaboration system of mankind. This system is built on interdependent trust. As a monkey, you always have to be alert: Some other monkey might steal your food when you look away. For humans, however, it comes in handy to share our viewing angle with others. By sharing our viewpoint, we are able to collaborate. Whatever is interesting to one person, could be relevant for you as well.

So, why should neuromarketing care?

Viewing angles are not just an important aspect of social interaction; marketeers can learn a lot from it too. Attention is scarce and the amount of content we see every day keeps on growing. Grabbing and retaining a consumer’s attention is more important than ever!

Are you curious to find out how attention-grabbing your advertisement, website or store is? Then you should use Eye Tracking. This technique is used frequently to record viewing patterns. In this guide, you’ll read how Eye Tracking works precisely and what insights it might give you.

How does Eye Tracking work?

Using Eye Tracking, we can measure at what and for what period people are watching something very accurately. The Eye Trackers follows every eye movement to the millimeter, by assessing the location of the pupil. By doing this, we are able to examine which components of an image grab the attention, distract the participant, or are ignored by the participant.

At Unravel Research, two different eye trackers are used. For online research, the Eye Tracking Bar is the way to go. This is a bar that is attached to the bottom of a computer screen. Using infrared cameras, viewing patterns are registered.

eye tracking screenshot

Some types of research demand more freedom of movement or are simply cannot be carried out online. Examples are when we’re researching a store environment or would like to know more about how consumers see an advertising brochure. In those cases, the mobile Eye Tracker is put to the task.

The mobile Eye Tracker is a pair glasses the participants wear during the scope of the research. They feel like a normal pair of glasses, hence giving the participant no restrictions in their movements.

eyetracking in supermarkt tobii glasses 2

All right, both a docked Eye Tracker and a mobile Eye Tracker can be used for research. What research questions can be answered by Eye Tracking?

  • Is my product seen in the shelves?
  • What are visitors looking at on a web page?
  • Which elements are overlooked?
  • What are consumers looking at during a commercial?

Why use Eye Tracking?

Attention is crucial for an advertisement’s effectivity.

However, you’re not always conscious of your own attention. Per second, our eyes shift in direction three to four times. Luckily, this usually goes about unnoticed. Our brains are excellent in converting all the eye movements to a stable representation of the outside world. A disadvantage to this is that it’s pretty difficult to figure out what people are looking at precisely.

Thankfully, this is not difficult to figure out if you’re using an Eye Tracker. This technique maps viewing patters in an exact way. It is extremely valuable to gain an insight in the attention processes of a consumer when they are watching your commercial, website or store. It enables you to figure out which elements catch your customer’s eye (pun intended), and which elements are skipped.

It gets even more valuable when you can also assess what someone’s is thinking and feeling while recording their eye movements. At Unravel Research, we can make this happen. Eye Tracking and EEG are two peas in a pod. EEG technique is used to measure to what extent a commercial is able to linger in the mind, how easy (or difficult) it is to process, and even whether or not it is able to increase sales. Read more on how EEG is used in neuromarketing research in this blog: https://www.unravelresearch.com/en/blog/how-does-neuromarketing-eeg-research-work

When is Eye Tracking used as a research method?

Eye Tracking for commercials

One of the most common situations in which Eye Tracking is used as a research method is when commercials are being researched. Because commercials are moving images, it is even more important that the right elements of each shot can be highlighted. Eye tracking can help shed a light on this matter.

Would you like to more about Eye Tracking for commercials? Read this blog: https://www.unravelresearch.com/en/blog/eye-tracking-in-advertising-did-they-see-my-ad

Eye tracking for printed advertisements

Printed advertisements are also put to the test with Eye Tracking Research. Printed ads can contain quite the amount of information, with the risk of a reader being overwhelmed by the amount of content. Eye tracking provides an insight in the viewing patterns of the reader.

Eye tracking for websites

Which elements of your website grasp the visitor’s attention? Which elements are overlooked? Do visitors see your home page in the order you want them to? Or do they miss the essential steps toward conversion? Eye tracking can answer all these questions, and more.

Would you like to know how Eye Tracking can contribute to a more user friendly and more persuasive website? Take a look at this blog: https://www.unravelresearch.com/blog/eye-tracking-voor-websites-zo-maakt-u-uw-site-gebruiksvriendelijker-en-overtuigender

Or would you like to know what else is possible in the neuromarketing field and usability? You can find a complete neuromarketing usability guide here https://www.unravelresearch.com/en/blog/complete-neuromarketing-usability-guide-methods-costs-cases

Eye tracking in-store: Shelf research

A shopping environment is the perfect place to apply Eye Tracking technology. From the first second a consumer walks into a store, his attention goes crisscross the space.

What drives a consumer when he is navigating through a store? Are discount deals being noticed? What is the consumer searching for when he is looking for a specific product? All these questions are answered easily by Eye Tracking.

Eye tracking in VR

In some cases, it is not possible to conduct Eye Tracking research in a physical environment. For example, when the product hasn’t been launched yet. Or when you’d like to test several different types of store layouts, but is too much work to keep renovating the store.

Then VR might be perfect for you.

The (store) environment is recreated using virtual reality. Put the VR glasses on and feel like you are in the test environment, with a 360 view, and the possibility to pick up products or other objects. Of course, the VR glasses come with an Eye Tracker to register what the eyes are looking at precisely.

What insight will Eye Tracking give me?

The output of Eye Tracking research consists of video. On these, we can see at what the participant was looking at during the research. Like a pointer, the dot follows the viewing pattern of the participant.

However, the eye tracking data of one participant are not necessarily binding for the effectivity of the commercial, website, or shop layout.

That’s why we combine the videos of all participants in one heatmap. This is a clear display of the viewing patterns of all participants. On the heatmap, you can see how often each location in the video is seen. The redder the color on the heatmap, the more often the participants observed this area.

A small change in the visual content can bring about huge changes in the heatmap. Take a look at the advertisement depicted below.

heatmap eye tracking baby facing forward

This advertisement shows a baby, that’s looking straight at the camera. Next to him is a stack of diapers and some text. The colors of the heatmap show that all elements are being seen. However, one of the elements outperforms the others: The baby’s face.

Now, look at the next advertisement. Even though the only difference is the position of the baby, the heatmap looks completely different.

heatmap eyetracking baby facing right to text

The baby’s face still is a popular element in the advertisement. However, the audience now pays more attention to the text.

How did this happen?

Do you remember the first paragraph of the blog? We discussed others’ viewing direction and its influence on your own viewing pattern. This advertisement is a classic example of this effect. Because of the viewing direction of the second baby, looking at the text next to him, the one looking at the ad will follow this behavior. Hence, the text in the second advertisement is read better than the text of the first.

Area of Interest Analysis

After analyzing the total advertisement, website, or store, you often want to analyze specific elements. Is the brand logo at the beginning of the commercial being noticed? And does the weekly offer catch the visitor’s eye? These insights are retrieved with an Area of Interest (AOI) analysis. The following information obtained with an AOI analysis:

Time until first fixation

How long does it take before an element first catches the eye? This indicate the capability of the element to grasp someone’s attention. 

Duration of fixation

How long does the eye stay at this element? This indicates shopping power. The interest in the element. Can it retain the eye or will the eye wander to the next fixation point?

Total duration of fixation

After an element has been perceived, the eye might come back to this location. The total amount of time spent looking at an element indicates motivated attention.

Number of fixations

The number of times the participant returns to a certain element. Attractive, interesting elements are viewed more often than less attractive, boring elements.

Eyeball count

This number illustrates how many people perceived the element. If many or all participants have watched an element, we can state that there is a universal interest in the element. Did only a small number of participants look at the element? It could be that these viewing patterns stern from personal interest.

Will Eye Tracking also work in VR?

Yes, it does!

Though VR is mainly known for its application in gaming, a growing number of research purposes have started using it too. However, there is a big difference in the basic requirements for its technology. Contrary to VR for gaming purposes, VR for research purposes requires a more precise measurement of the viewing direction. We don’t want to know that a participant looked at a product in the left bottom corner of the shelf – we want to know which exact product they were looking at.

Development in the field of VR do not beat about the bush: When using a special type of gloves, it is even possible to simulate your own hands in the virtual environment. Suddenly, it’s possible to actually grab products from the shelf to take a better look.

Just like a real store setting.

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