Understanding Eye Tracking: Seeing Through the Eyes of Your Participants

What is Eye Tracking?

Eye tracking is a powerful technology that measures where a person is looking or how their eyes move in relation to their head. These movements are usually recorded by a pupil camera and measured by the reflections of tiny projected lights. Using specialized devices known as eye trackers, researchers can gain valuable insights into human behavior, perception, and cognition by measuring where and how the eyes move.

Why Eye Tracking?

Eye tracking is a powerful method for understanding where participants look during testing sessions. Also known as gaze tracking, it provides researchers with precise data about where someone is looking, for how long, and in what sequence. This technology serves as an essential measurement tool that reveals insights impossible to gather through conventional observation or interviews alone.

Scientists use eye tracking to study perception, language processing, and neurological disorders, while marketers leverage it to refine advertising, optimize user experiences, and decode consumer behavior. Beyond these fields, eye tracking is making strides in assistive technology, enabling individuals to control devices with their gaze, and even showing promise in the early detection of autism.

Limitations

When properly implemented, eye tracking can answer crucial questions about the effectiveness of online advertising, website usability, and fundamental scientific research. However, it’s important to understand that an eye tracking system is fundamentally a measurement instrument. Without clear objectives and proper interpretation methods, its value remains limited. The real power comes from knowing exactly what you want to measure and why.

People with very dry or very dark eyes may be hard to track. The first group because of unclear reflections, the second group because of the hardly visible difference between iris and pupil.

The Value of Gaze Analysis

Gaze tracking analysis reveals not just where test participants looked, but also the sequence and duration of their attention. This provides unique insights that neither traditional observation (even with tools like Mangold INTERACT) nor questionnaires can uncover. For usability studies in particular, understanding exactly why a participant clicked on certain elements becomes clear when you can see their complete visual journey.

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Prerequisites for Eye Tracking Studies

To conduct effective eye tracking research, several key components are necessary:

First, you need a device capable of measuring (or more accurately, tracking) a participant’s eye movements. Quality systems like the Mangold VT3 Mini provide this capability. Additionally, you’ll need software that can both record and analyze the eye tracking data.

You’ll also require a program capable of presenting stimuli – anything you want to show participants during a controlled test situation and that needs to be analyzed per stimulus later. With these elements in place, along with a suitable computer and appropriate test participants, you have everything needed for successful gaze tracking studies.

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Creating an Eye Tracking Project

A comprehensive eye tracking software package should include three essential components:

• A project manager for organization
• A recorder for capturing eye tracking sessions
• An analysis tool for processing the collected data

When designing a project, you’ll typically define a series of stimuli to present to participants. These might include:

• Static images
• Videos
• Interactive websites
• Software interfaces

For usability testing that involves participant interaction with websites or software, screen recording becomes essential. This captures everything happening on the monitor during the test session, including mouse movements, keyboard inputs, and all on-screen activities.

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The Eye Tracking Session

Before beginning data collection, an important calibration step is necessary. The system must understand how each participant’s eyes move and relate to screen positions. This typically involves having participants look at several points on the screen – usually five points, one in each corner and one in the center.

During this brief calibration, the system creates a mathematical model of the participant’s eye movements. Once calibrated, the system can accurately convert any gaze position to screen coordinates, allowing for precise tracking throughout the session.

Common Questions About Eye Tracking

Some frequently asked questions about eye tracking include:

Does it work with glasses or contact lenses? Yes, modern systems like MangoldVision and the VT3 mini Eye Tracker generally work well with both.

Can participants move freely? Yes, within reasonable limits defined by the system’s “headbox.” Natural movement during both calibration and testing is actually beneficial.

What happens if someone looks away or blinks? Quality systems can instantly resume tracking when the eyes return to the screen, operating at millisecond-level precision.

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Data Analysis and Visualization

Eye tracking data provides insights into how long, how often, and in what sequence elements were viewed. To analyze this effectively, researchers typically define Areas of Interest (AoIs) – specific regions on a stimulus where viewing behavior is to be measured.

Modern analysis tools offer several visualization methods:

Focus Maps: Unlike traditional heat maps, focus maps (pioneered by Mangold) show only what participants actually saw, providing a more accurate representation of visual attention.

Gaze Plots: These show the sequence and pattern of eye movements across the stimulus.

Areas of Interest (AOI) Analysis: Allows for detailed statistical analysis of viewing behavior in specific regions.

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Professional Eye Tracking Solutions

For professional eye tracking research, Mangold Vision offers a comprehensive solution combining sophisticated software with precise hardware technology.

Discover Mangold Vision

Learn more about our professional eye tracking solutions.

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Frequently Asked Questions about the Mangold Vision Eye Tracking System

1. Is the Mangold Vision Eye Tracker suitable for studies with children?

Yes. Eye Tracking studies with Mangold Vision and children were done in the past and achieved good as well as significant results.

Some examples are: Bolden, D., Barmby, P., Raine, S., Gardner, M. (2015): „How young children view mathematical representations: a study using eye-tracking technology”, von Rader, N., Zukow-Goldring, P., Miller, S. (2013): „Dynamic synchronous gestures assist word learning in low functioning ASD Children” und Elician Celine Wartman, Nancy Riccardi, Nancy Rader: „Gaze Patterns to a Speaker’s Face in Typically Developing and ASD Children”. Downloads and links to these publications can be found here .

2. Is the so called head motion range important for data accuracy?

This range, aka “head box” is no indicator for the accuracy of an Eye Tracking System. It only indicates the spatial area (width, height, depth) where the eye tracking camera can (still) capture the participant’s eyes. I.e. this range denotes the movement range, the participant is allowed to make during a test, without losing the gaze data of that person. The VT3 mini head box is really big (WxHxD): 31.5 x 22.5 x 35 cm (12.4 x 8.9 x 13.8 in). It is unlikely that a participants is moving out of that range during a test, unless she/he is very restless.

Thus, the myth of “The bigger the head box the better” is not entirely true, because precision of gaze data is much more influenced by some other factors:

All eye tracker calculate a mathematical model of the participant’s eyes during calibration. This model represents the position of the test person´s eyes in relation to the screen. All eye movements are subsequently mapped to points on the screen, based on this mathematical model. So, the better the subject’s behavior during calibration matches the behavior during the session, the more accurate the calculated gaze points will be.

An important data accuracy factor is also the speed of image processing. Here, Mangold Vision is taking the lead. The Mangold Vision eye tracker has an integrated on-board computer where the image processing takes place (Instead of processing the images on the connected PC). With that high speed on-board processing, all the image data is processed immediately. In this way, head motions are compensated really fast and the recorded data has a reliable quality.

3. How does calibration work?

At the beginning of each test, a 5, 9 or 16 point calibration is executed. In our experience, a 5 point calibration is sufficient, because other factors are decisive. It is advisable to show instructions and user data forms that need to be filled in BEFORE the calibration, as the postion of the pariticpant will most likely differ if the test itself only includes images and videos to watch. We recommend to adjust the calibration background color to match the average light condition of your stimuli, because the pupil size is automatically influenced by the ammount of light comming from the screen.

4. What’s the typical operating distance?

With the VT3 mini Eye Tracker, a distance between user and screen of 60 cm (24.6 in) is ideal, because the camera optics is optimized to this. Including the above mentioned head box, this results in a total range of 45 – 80 cm (17.7 – 31.4 in), which is a common and ideal computer working distance.

For large displays Mangold offers so called long distance eye tracker, which work on really large screens and in a distance of several meters (several 40 inches). They can be used e.g. for museums, supermarkets or shopping malls or multimedia installations.

5. Can it be used with people wearing glasses or lenses?

Glasses and contact lenses are not influencing the eye tracking test, as long as the light conditions do not produce reflections on those glasses which make the pupil invisible for the eye tracking camera. This can easily be handled by creating appropriate light conditions. Also glasses with very small frames may cover the pupil in certain head positions.

6. What happens if the participant looks away from the screen?

Blinking and looking away from the computer screen is unproblematic, because the gaze tracker re-tracks the eyes very fast, when the participant looks back on to the screen and her/his eyes re-appear in the tracker’s field of view.

7. On which computer systems can the Mangold Vision system be used?

Mangold Vision runs on almost any modern Windows PC, from Win 10 and higher. You can even use your own computer or get a recommended system from Mangold.

8. How user-friendly is the Mangold Vision Eye Tracking system?

The VT3 mini Eye Tracker is small (size 25.4 x 2.6 x 3.2 cm), light-weight (0.21 kg) and protected with a robust aluminum housing. With only one USB cable that is plugged into the PC/laptop, it is very easy to setup.

Depending on your hardware, the eye tracker is placed directly underneath the screen or at the laptop keyboard with our supplied stand, or mounted directly under the screen with the included magnetic strip. .

The entire calibration process and all data recording works automatically. The Mangold Vision recording system is designed to work as a one-push-button solution.

9. What has the highest impact on data quality and on expected results?

The design of your individual study is the most influential force! The question you should always ask yourself: “Can we answer the desired research questions with this study. And are the subjects appropriate for this kind of data collection?”

The second important factor is the test leader / moderator who should make the test person feel comfortable, so that she / he behaves “natural” and “concentrated”.

Last but not least, the lighting conditions during the test are important: Make sure that there are no additional reflections from ceiling spotlights or other lights to ensure that the gaze tracking camera can track the eyes consistently and that the subject’s position does not vary much from the calibration position.

10. Which kinds of stimuli can be presented during my eye tracking tests?

A multitude of different stimuli can be presented through Mangold Vision on the computer screen: Images, videos, EPrime tests and all activities which can be performed on the computer, like surfing the web, using a PC application (games, chats, forums, social media applications, collaborative working applications etc.).

11. Which kind of analysis offers the Mangold Vision Eye Tracking System?

The Mangold Vision Analyzer offers various methods of visualizing the recorded gaze data and turning them into statistical results.

Additionally, socio-demographic data or data from on-screen questionnaires can be collected during the tests. This allows for easy data selection during analysis and replay (e.g. “Show the data of all female users at the age of… who said … about the stimulus …“).

12. Can the user’s behavior be recorded as well?

Yes. Mangold Vision can record the user’s behavior and speech through a connected web camera. This video is replayed in sync to each recorded stimulus during analysis. It allows to better understand a user’s gaze pattern, because it shows the user’s context and lets you hear the user’s spoken comments. Both add a high value to almost any observational study.

13. Is it possible to add EEG and other physiological data to studies done with Mangold Vision?

Yes. Watch this video https://www.youtube.com/watch?v=sEbQdwk4iKY and read more about Mangold DataView.

Combining Mangold Vision and Mangold DataView allows you to do even very complex neuro marketing studies.

14. Is the Mangold Vision system portable?

Yes, sure. The VT3 mini Eye Tracker is easily portable (size: 25.4 x 2.6 x 3.2 cm), very robust because of its light-weight metal housing. Therefore, it is ideal to carry-on for field studies.

Discover Mangold Vision

Learn more about our professional eye tracking solutions.

Explore Mangold Vision