Eye tracking helps developmental researchers to explain growth and transformation in perceptual, cognitive, and social abilities from infancy through young adulthood.
Long before infants or young children can talk, eye tracking can provide detailed information about how they percieve the world. Applicability of eye tracking within the field of developmental research is broad, including studies of:
- Developmental progression in infants’ allocation of attention and interest
- Visual perception related to understanding and recall
- Ability to recognize motion signals
- Development of control of action
- Social interaction characteristics
- Oculomotor functions
- Language acquisition
Eye tracking has been used to explore infants’ ability to categorize visual and auditory events, perceive object unity, represent temporarily occluded objects, and scan dynamic human faces.
Detailed spatial and temporal eye tracking data
Scanning patterns provide valuable information about how infants distribute their attention and interest as they scan different images or dynamic events. Saccade latencies give information about when infants shift their gaze between two locations, allowing researchers to study predictive and reactive gaze shifts. Being able to time-lock and asses eye movement data over time allows studying learning functions and how infants’ attention changes over a stimulus set.
Eye tracking to study object representation
Much research has been carried out to understand how infants remember (represent) temporarily non-visible (or occluded) objects. Eye tracking can provide a detailed description of how infants’ actions are directed to ongoing occlusion events, by determining when their gaze shifts from one location to another (saccade latencies).
The eye tracking figures below, also from research at Uppsala University, show the ability of five-month old infants to represent temporarily occluded objects (to the left) and how seven-month old infants assume that occluded objects will continue (to the right).
> Gaze replay video from the same object representation study.
Eye tracking in studies of social cognitive development
In research of social cognition and understanding, eye tracking is used to study how infants and children look at other people performing goal-oriented actions or engage in social events. By analyzing infants’ scanning patterns, researchers can answer questions such as:
- How do children understand what other people do, think or feel?
- How do we come to understand the actions and intentions of other people?
- How does the ability to synchronize our actions with those of others around us and to do things with others develop in babies?
The Baby Lab at the Department of Psychology at Uppsala University in Sweden uses eye tracking to study differences in social interactions in normal children and children with Autism. These figures show how an Autistic child (to the left) and a normal subject (to the right) perceive social interaction.
Development of the ocular motor system
Eye tracking is an invaluable tool in research aimed at understanding how infants develop control over the ocular motor system and how different gaze components (smooth pursuit, saccades, and head movements) are integrated. Typically in such studies, infants are presented with objects that move back and forth on sinusoidal trajectories, and eye tracking is used to measure their eye and head movements as they look at these objects.
Automated preferential looking paradigms
Registering eye and head movements, Tobii eye trackers enable use of preferential looking paradigms in an objective and automatic way. This technique is commonly used in language acquisition studies.
Tobii eye tracking solutions
Tobii eye trackers are known for their unique tolerance for large head movements, allowing subjects to move naturally. This makes them particularly suited for infant studies or studies that involve children. Our range of remote eye trackers includes eye trackers for on-screen stimuli display, standalone eye trackers for studies of real-world stimuli, and eye trackers that offer a combination of both.
The Tobii TX300 Eye Tracker offers 300 Hz sampling rate for eye tracking studies that require a higher sampling rate; e.g. the need to study eye movements such as saccades, correction saccades, fixations, pupil size changes and blinks. Sophisticated technology allows head movements to be subtracted from gaze direction data, thus measuring real eye movements.
The unique combination of a higher sampling rate and large head movement box enables unobtrusive eye tracking research of infants and children. The wide, high-resolution screen enables automated preferential paradigms, and closely fills a child’s field of view in a natural way that is appealing and captures attention.
The system can be synchronized with most EEG systems, including Brain Products, EGI and ANT via E-Prime, for instance.
Tobii Studio eye tracking software provides efficient tools for visualization and AOI analysis of scanning patterns and other data. Customized calibration routines for infants and other subjects with limited attention makes calibration fast and easy, reducing the amount of time needed to calibrate each child. It is easy to set up bold, attention-grabbing stimuli using video and audio.
A range of other applications are compatible with Tobii eye trackers, including Tobii Toolbox for MATLAB and E-Prime Extensions for Tobii. Researchers who want to develop their own eye tracking applications can download the Tobii Software Development Kit at no cost.