Developmental Research: what is eye-tracking?

How babies and children look at things can give us a huge insight into how they make sense of the world around them. In our labs at the University of Sussex, the Sussex Baby Lab and the Nature and Development Lab, we use eye tracking to understand how infants and young children see, explore, and make sense of their environments.

What Is Eye Tracking?

Eye tracking is a non-invasive method that tells us exactly where someone is looking on a screen, moment by moment. It helps us see the world through their eyes, see what grabs their attention, what they ignore, and how they shift focus over time. These insights help us learn how attention, perception, memory, and learning develop in the early years. We use eyetracking because it captures childrens' natural looking behaviour without them even noticing.

Here is an example of a child participant watching this video. The red area shows us exactly what they're looking at. [Data collected by Taysa-Ja Newman]

The Eye Tracker We Use

In our labs, we use the EyeLink 1000 Plus, a high-precision eye tracker designed by SR Research. It uses infrared light (invisible and safe) to track the position of a person's eyes. This setup is entirely safe and non evasive.

Here is our eyetracking camera on the desk between the baby and the screen [Photo by Philip MacAdams]

Here’s how it works:

• The infant or child sits comfortably in front of a screen (usually in a car seat, or sometimes on a caregiver’s lap).

• We put a little sticker on the child's face, this sticker helps the camera work out where there is a face, no matter how much your child might be wriggling around!

• The eye tracker sits on the table in front of them and shines a light. It then uses its camera to detect the tiny reflections from this light that bounce off the eye.

• Software then calculates exactly where the child is looking, second by second.

After your session, the only data we keep is your child’s eye movement data, there’s no recording made of their face. (The only exception is if you're taking part in a study that also looks at facial reactions, but if that’s the case, we’ll always let you know beforehand.) All data is stored securely using a participant number, never your child’s name, so their identity is fully protected.

If you're a caregiver and curious about how eye tracking works or want to learn more about the methods we use, we’d love to hear from you! We're always happy to chat about the research happening in our labs.