Having raw access to high quality eye data gives researchers access to another biometric tracking point and offers insight into the human psyche. With well-designed experiments, scientists have and will continue to expand our understanding of how humans process the informational world.
Pupil dilation has been identified as the most reliable approach to recognize emotion because it is easy to detect and is controlled by the automatic nervous system. This can be used as a means to improve our understanding of human-computer interactions, social relations, mental health and human behavior. Studies have initially shown a higher increase in pupil dilation during negative emotions compared to positive ones, and steeper, higher, more sustained and longer dilation happens in response to highly arousing negative stimuli.1
Several studies have reported how the pupil dilates during decision-making. One of them even reported how pupil dilation differentiates between “yes” and “no” choices for conservative subjects deciding yes against their bias, meaning that pupil dilation reveal the content of the evolving decision and the decision maker’s attitude.2
Additionally, pupil dilation has been found to detect surprise in participants, that is, errors in judging uncertainty. Since our decisions are guided by the rewards we expect and these are often uncertain, pupil dilation is a measurable data point to understand if a decision lead to an expected outcome or not.3
Information Gathering Techniques
A simple but powerful tool, understanding where and how a user interprets visual information, including text and images, has huge implications. Eye movement data has been shown to reflect the cognitive processes in this area for tasks such as reading, music reading, typing, visual search and scene perception.4
Studies have also shown that eye tracking can measure mind wandering, a ubiquitous phenomenon in which attention shifts from task-related to task-unrelated thoughts.5
Cognitive Load Understanding
Eye behavior has been found to be a good predictor of a human’s current cognitive load.
One study used eye fixations to measure the mental workload of professional pilots engaged in simulated flights.6 Another study investigated the differences in visual scanning of instruments between expert and novice pilots, and found that expert pilots have better scanning strategies and are more flexible to adapt their behavior in response to changing tasks.7
A. Babiker, I. Faye and A. Malik, “Pupillary behavior in positive and negative emotions,” 2013 IEEE International Conference on Signal and Image Processing Applications, Melaka, 2013, pp. 379-383, doi: 10.1109/ICSIPA.2013.6708037. ↩︎
Preuschoff, Kerstin & t Hart, Bernard & Einhäuser, Wolfgang. (2011). Pupil Dilation Signals Surprise: Evidence for Noradrenaline’s Role in Decision Making. Frontiers in neuroscience. 5. 115. 10.3389/fnins.2011.00115. ↩︎
Di Nocera, Francesco, et al. “A Random Glance at the Flight Deck: Pilots’ Scanning Strategies and the Real-Time Assessment of Mental Workload.” Journal of Cognitive Engineering and Decision Making, vol. 1, no. 3, Sept. 2007, pp. 271–285, doi:10.1518/155534307X255627. ↩︎
Bellenkes, A. H., Wickens, C. D., & Kramer, A. F. (1997). Visual scanning and pilot expertise: The role of attentional flexibility and mental model development. Aviation Space and Environmental Medicine, 68(7), 569-579. ↩︎