By Jana Riethausen
The eye is much more than just a sensory organ – it is a unique window into our inner state. Its direct connection to the brain offers extraordinary possibilities to understand our behavior and cognitive performance.
Imagine being able to detect in real-time the cognitive strain an employee experiences during a critical process — this could significantly enhance safety. Or consider observing how quickly and safely an aspiring paramedic or emergency responder navigates an acute emergency, allowing for targeted improvements in their training.
Eye tracking technologies, combined with modern analytical methods, make exactly this possible. They open up entirely new perspectives on improving safety in areas such as mobility & transportation, manufacturing and emergency services.
The Eye: More Than Just Vision
Up to 80% of our perception is processed through vision, making it our most dominant sense. The retina plays a crucial role in this process, as it is technically an extension of the brain. This means that visual stimuli are processed directly in the brain, with almost no delay.
This makes the eye an integral part of the nervous system that not only conveys external impressions, but also reveals deeper information about our cognitive and attentional states.
Decoding Behavior, Optimizing Attention: Eye Tracking in Practice
How much can our eyes really reveal about us? With eye tracking, it is possible to accurately record diverse eye dynamics such as eye movements and fixations, changes in pupil size, blink rate – even in challenging environments, thanks to robust eye-tracking glasses. The data collected provides an impressive range of insights.
1. Attention and Focus
What draws our gaze? Eye tracking pinpoints where people focus their attention in specific situations. Particularly revealing are so-called fixations — moments when the eyes pause on a single point to absorb information. The duration and frequency of these fixations provide insight into which areas are perceived as particularly relevant. Heatmaps visually represent this data, making the distribution of attention easy to analyze.
In safety-critical environments like aviation or rail transport, eye tracking helps to ensure that operators focus on crucial displays and controls. Have you ever wondered whether trainees are truly focusing on the most important elements during complex tasks? Scattered or inconsistent gaze patterns can indicate overload — providing valuable feedback for targeted improvements in training.
2. Stress and Fatigue
How do our eyes respond to stress or exhaustion? Under stress, people show more erratic, less focused eye movements. Conversely, fatigue often results in slower eye movements and longer fixations as mental capacity decreases. Frequent, prolonged blinks can also be a sign of exhaustion.
In safety-critical professions and industrial environments, these insights can help prevent safety risks caused by mental strain or fatigue. Eye tracking makes it possible to detect stress and fatigue early, allowing for timely intervention to reduce the risk of errors.
3. Cognitive Load
How mentally demanding is a task? Changes in pupil size and eye movement patterns provide key indicators. It has been shown that mentally challenging tasks, such as mathematical operations, generate an increase in pupil size. While exploring a scene, longer fixations on a particular point may indicate that a person is using more cognitive resources to process information. Similarly, a high number of fixations in one area may indicate that the information is particularly complex or challenging.
Gaze paths or saccades (rapid eye movement between fixation points) also provide clues: Clear, goal-directed patterns indicate low cognitive load, while chaotic or erratic gaze shifts often signal cognitive overload.
4. Emotional Reactions
Did you know that our pupils reveal emotions? During emotional arousal — whether from joy, excitement, or stress — pupils naturally dilate. The more intense the emotional response, the more pronounced the pupil dilation. Blinking also reflects emotional responses: Nervousness or stress increases the blink rate, while deep concentration reduces it.
These subtle changes allow for the objective measurement of emotional responses — helpful for identifying stress triggers. In this way, eye tracking can help adapt work and learning processes to better meet individual needs.
Unlocking Human Performance Through Eye Tracking
Our eyes do more than just see — they reflect how we process the world around us. From tracking attention shifts to detecting cognitive overload, eye movement patterns provide a direct window into human behavior. Understanding these subtle cues allows us to optimize safety, decision-making and efficiency in complex environments and situations.
As eye tracking technology becomes more robust and suitable for real-world applications, its role in enhancing situational awareness and preventing mistakes continues to grow. By better understanding how people engage with their surroundings, we can create safer, more efficient work environments and redefine the way we train and support individuals in critical roles.
INSIDE EYE TRACKING: FOUR QUESTIONS FOR ALEJANDRO GLORIANI, R&D SENIOR DEVELOPER AT VIEWPOINTSYSTEM
EDITORIAL TEAM: Alejandro, why do our eyes reveal so much about our mental state?
Alejandro Gloriani: To explain this, we need to distinguish between sensing and perceiving. Sensing refers to the process that takes place in the different sensory organs, for example, the retina senses light and sends that information to the brain.
Perception, however, is the processing of this information by the brain, and this is when the effects of our physical and mental state manifest themselves. It is as if our computer had many heavy processes running simultaneously, no matter how much memory and high performance it has, if we overload it enough, we will see the effects of that overload in different ways (the processes run slower, the computer freezes, etc.).
Something similar happens in our brain, but what makes the visual system special is that, unlike other sensory modalities, it can externalize real-time feedback about the state of the nervous system that would otherwise be very difficult to obtain.
Why do we move our eyes and how many types of eye movements exist?
In short, humans move their eyes because our retina has a higher resolution area called the fovea. In general, when we perceive something moving in our peripheral vision or we are interested in something, we move our eyes to be able to see it in high resolution with our fovea.
However, our eyes are never still. Even when we are focusing on something, the eyes make very small movements, of which we are not aware. So, there are different types of eye movements, that can be grouped in three categories, gaze-shifting eye movements, gaze-holding eye movements and fixational eye movements.
Which specific types of eye dynamics do you find most insightful?
Two ocular dynamics that provide very valuable information are saccades (from the gaze-shifting eye movements group) and fixations. By studying them in a combined way, a lot of information can be extracted about a person’s attention and cognitive state.
Fixations reveal which elements are perceived as relevant, while saccades show how a person scans and processes information. For instance, long and frequent fixations often signal cognitive effort, while erratic saccades can indicate stress or overload. This makes them particularly useful in areas like training simulations or real-world performance analysis, where tracking attention shifts can help optimize learning and decision-making.
What should be given special attention to when recording eye movements to ensure accurate results?
The most important thing is to obtain raw data of the highest possible quality, otherwise the results of subsequent analysis will not be reliable. As a general advice, but especially in cases of visual impairments, it is recommended to perform an individual user calibration. This is a simple yet essential step for achieving optimal data quality.
SELECTED LITERATURE
- Shannon P. Devlin, Noelle L. Brown, Sabrina Drollinger, et al. Scan-based eye tracking measures are predictive of workload transition performance. Applied Ergonomics 105 (2022).
- Erdinç İşbilir et al. Towards a Multimodal Model of Cognitive Workload Through Synchronous Optical Brain Imaging and Eye Tracking Measures. Frontiers in Human Neuroscience (October 2022).
- Andrew T. Duchowski, Krzysztof Krejtz, Nina A. Gehrer, et al. The Low/High Index of Pupillary Activity 2020. Association of Computing Machinery (2020).
- Hao Wu, Jinghao Feng, Xuejin Tian et al. EMO: Real-Time Emotion Recognition from Single-Eye Images for Resource-Constrained Eyewear Devices. Association of Computing Machinery (2020).
- Steven Hickson, Nick Dufour, Avneesh Sud et al. Eyemotion: Classifying facial expressions in VR using eye-tracking cameras. IEEE Winter Conference on Applications of Computer Vision (2019).
- Soha Rostaminia, Addison Mayberry, Deepak Ganesan et al. iLid: Low-power Sensing of Fatigue and Drowsiness Measures on a Computational Eyeglass. ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, Vol. 1, No. 2, Article 23 (June 2017).
