Eyetracking. How do you measure babies’ attention?

Understanding the neurocognitive development of babies is based on identifying what they look at, what they interact with, and how they perceive their environment. One of the basic capacities that it uses is visual attention. This is defined as the process, voluntary or involuntary, in which the human brain takes in a large amount of visual data, but pays attention to only a small part. Visual attention is focused on previous experiences and long-term memory expectations.

Hand in hand with neuroscience, the technique of monitoring eye movements or “eye-tracking” allows you to continuously record the baby’s gaze, what she is looking at and what elements call her attention. This allows us to objectively and quantifiably measure her visual attention and her abilities to process visual stimuli at an early stage of her development. Thus, through the analysis of ocular activity and selective attention at each moment, we can draw conclusions about its neurocognitive development, but how is attention measured and analyzed?

The operation of this technique basically consists of the use of a camera together with infrared lighting sensors that track and monitor the pupil and the movements of the eyes. The information obtained is very complete and with high precision, since it allows recording ocular activity in microseconds.

Pupil detection and eye tracking

The type of eye movements that are measured and analyzed to identify those elements or areas that attract the most visual interest of babies and decipher patterns in their development behind how they see stimuli (videos and images) are various.

One of the basic registration units are fixations, saccadic movements and gaze sequences.

  • Fixations are the periods in which the eyes are still, focused because they are absorbing information. Its duration time can vary between 100 to 300 milliseconds.

Fixation (red circle)

  • Saccadic movements are rapid movements that occur between fixation and fixation. They usually represent periods of visual search during which there is no acquisition of specific information.

Saccadic movement (line)

  • The gaze sequences represent the sum of fixations and saccadic movements. The sequence of straight and fast gazes indicates an efficient and specific visual navigation of the stimulus.


After data collection, the next step is to continue with the analysis of the results obtained. Let us remember that one of the main objectives of the BiSC project, in collaboration with the Attention, Perception and Language Acquisition Laboratory (APAL) of the University of Barcelona, is to assess whether there is any association between the levels of air pollution and neurocognitive development in stages early.

Thank you very much for reading and for the participation of all the volunteers in our studies! Together we do science.


News written by Jessica Sánchez-Galán, research technician of the BiSC project.