What is eye tracking?

They say the eyes are the window to the soul, but they’re also the gateway to knowledge about how people gather information and what influences their actions and decisions. The concept of studying where we look has been around since the 1800s, and today modern eye tracking technology allows us to gather an unrivaled amount of insight into the human mind.

Technically speaking, eye tracking is the process of measuring eye movements to determine where a person is looking, what they are looking at, and for how long their gaze is in a particular spot. Because our eyes are one of the primary tools we use for decision making and learning eye tracking is commonly used by researchers and businesses looking to study human behavior because it’s the only way to accurately and objectively measure and understand visual attention.

How does an eye tracker work?

An eye tracker uses invisible near-infrared light and high definition cameras to project light onto the eye and record the direction it’s reflected off the cornea. Advanced algorithms are then used to calculate the position of the eye and determine exactly where it is focused. This makes it possible to measure and study visual behavior and fine eye movements, as the position of the eye can be mapped multiple times a second. How quickly an eye tracker is able to capture these images is known as its frequency. A recording can also be made of the scene a person is looking at, and using eye tracking software it’s possible to produce a visual map of how the person viewed elements of the scene.

In this blog post we will explore the range of eye trackers available, what types of research each is most suited to, how to understand and interpret the results of your eye tracking study, and the unique benefits of using eye tracking in research.

What types of eye trackers are there?

While the general principal of how they work is the same, there are several different eye tracking device types available and the one most appropriate for the user depends on the nature of their research. The main groups are:

• Screen based – These are stand-alone, remote devices which either come as an individual unit or a smaller panel which can be attached to a laptop or monitor.
• Wearable – These include eye tracking glasses and virtual reality (VR) headsets with integrated eye tracking. 
• Webcam – Webcam eye trackers don’t have sensors or specialized cameras, they are solely comprised of the webcam device attached or built-in to a computer.

Screen based eye trackers are mostly used for research where the participant interacts or is exposed to the stimuli on a screen. These remote eye trackers offer broad sampling rates, and those with a high frequency can provide a large amount of data and a very high level of detail relating to the movement of the eye. Screen based eye trackers with a large tolerance for head movement are commonly used when studying people with certain medical conditions and infants who are unable to control their movements .

Eye tracking glasses are ideal for studying behavior in real-world situations such as browsing the aisles of a supermarket, playing sport, navigating the subway system, consuming media in the home, human interaction, or working in a factory etc. They allow natural movement and are unobtrusive, which means the wearer can do what they normally would in the situation. They also contain a built-in scene camera and microphone to record the environment.

Webcam eye tracking uses the built-in or external webcam attached to a laptop or monitor to collect information on where the person is looking. This method does not use infrared light beams or specialized cameras, instead it relies on the image generated from the webcam. An algorithm is then used to calculate the position of the head and eyes, and from that the direction of the eyes is correlated to an image on the screen. While the depth and accuracy of information you can get using this method is somewhat limited, webcam eye tracking enables large-scale studies and a fast turnaround which is ideal for quantitative research. This method is commonly used early in a design process, such as A/B testing of website or product design.

How do you get the results using eye tracking software?

The first step in any study is establishing what question you want to have answered. Specialized eye tracking analysis software is used to collate your data and give you the information you want. There are many programs you can use, but it’s important you correctly set up the study from the beginning. The level of information you’re able to get out of an eye tracking study will be determined by the type of tracker used, the program used to analyze the data, and the nature of your experiment. If you don’t have the time or expertise to collect and analyze your own data, a research consultancy can do this for you.

What are the benefits of eye tracking in research?

One of the main benefits of eye tracking is that it’s the only method which can be used to objectively and accurately record and analyze visual behavior. It would be impossible to ask someone scanning the aisles of a supermarket to recall, let alone quantify, the amount of time they spent looking at every item, or even exactly where they looked or what advertisements they noticed most. 

Eye tracking allows researchers to study the movements of a participant’s eyes during a range of activities. This gives insight into the cognitive processes underlying a wide variety of human behavior and can reveal things such as learning patters and social interaction methods. It also allows for the screening of atypical neurodevelopment and cognitive or perceptual disabilities. Eye tracking technology also provides a way for young children and those with neurological impairments, who are unable to explain their thought processes, to participate in studies.

Eye tracking:

• Reveals subconscious behavior – researchers can get insight into behaviors we carry out instinctively. 
• Provides unbiased, objective, and quantifiable data - it removes the need to try and remember or explain where you looked and prevents study participants assuming details and giving incorrect information.
• Allows for natural behavior – eye trackers are unobtrusive and allow tasks to be carried out as normal.
• Is versatile and mobile – it can be used in almost any environment and setting. 
• Provides a high level of detail – depending on the device and software, the results can offer a very high level of granularity for deep analysis. 
• Offers real-time information – with live streaming you can see the person’s gaze immediately.
• Is explanatory – it can depict processes and actions that are hard to articulate or explain.
• Offers a visual representation - AOI’s, heat maps’ and ‘gaze plots’ show the eye tracking results and how people have interacted with an environment or responded to a stimuli. 
• Adds value to other biometric data - it can be combined with EEG, ECG, EMG, GSR NIRS and more. Eye tracking can enhance the use of these devices by providing additional information about what led to the physiological responses. 

What are the main applications of eye tracking in research?

While there are almost endless fields in which this technology and research methodology could be applied, there are several which use eye tracking extensively. They include:

• Market Research – Eye tracking offers detailed and unbiased information about consumer behaviors and decision making processes. It allows market researchers and brand owners to study the process consumers undertake when viewing and selecting a product. It shows them what elements naturally attracted the most attention and what areas were ignored. Unlike surveys or questionnaires, eye tracking details authentic behavior which is useful when designing advertising, branding, packaging and product placement. 
• User Experience - There is no better way to test user experience than to view it through the eyes of the user. Eye tracking can be used to study the way in which platforms and services are used and how effectively they deliver their goals. Eye tracking can reveal design flaws and even methods of use which may not have been evident in the creative process. 
• Scientific Research – By studying visual behavior it’s possible to get valuable insight into development, learning patterns and signs of cognitive dysfunction or disease such as those seen in patients with Alzheimer's, Parkinson’s, schizophrenia, autism, depression, brain injury, and many more. Similarly, dyslexia and other reading or learning difficulties can be identified and studied by using eye tracking.

• Industry and Human Performance – Eye tracking can give valuable insight into the methods in which tasks are performed and processes implemented. Eye tracking is used by businesses to identify safety risks, operational inefficiencies, and to streamline training; all saving substantial amounts of time and improving productivity. Similarly, sports professionals and coaches can use eye tracking to identify skills and strategies to improve performance. Eye tracking gives a unique snapshot into tasks and actions which are carried out quickly and often subconsciously. With the video playback and gaze mapping, it’s possible to break complex and rapid processes into digestible information which can be studied and turned into training material.

Want to know more about eye tracking and its benefits?

There is a range of information on all the applications of eye tracking and more detailed explanations of specific research tools and their uses here. If you lack the resources to run your own eye tracking study; you can learn more about how our research consultancy can help you here.