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Published on: May 15, 2019
Seeing and looking: Evidence for developmental and stimulus-dependent changes in infant scanning efficiency
Shannon Ross-Sheehy1, Bret Eschman2, Esther E Reynolds1
1Department of Psychology, University of Tennessee, Knoxville, TN, United States of America.
Insights
Infant scanning efficiency develops with age, showing more efficient visual processing in 11-month-olds. Visual attention patterns also adapt to scene content and complexity, especially in social contexts.
Area of Science:
- Cognitive Development
- Infant Visual Perception
- Computational Neuroscience
Background:
- Infant attention research often overlooks detailed eye movement patterns.
- Understanding saccade and fixation dynamics is crucial for assessing scanning efficiency.
- Developmental changes in visual scanning efficiency are not well-documented.
Purpose of the Study:
- To investigate developmental changes in infant scanning efficiency.
- To examine how scene content and complexity influence visual scanning patterns.
- To assess the stability of individual differences in eye movement metrics.
Main Methods:
- Longitudinal and cross-sectional studies with infants aged 5-11 months.
- Assessment of scanning efficiency metrics: fixation duration, saccade rate, amplitude, and velocity.
- Infants viewed quasi-naturalistic scenes varying in social content and complexity (3, 6, or 9 elements).
Main Results:
- Individual differences in saccade rate, fixation duration, and saccade amplitude showed moderate to strong stability.
- Younger infants (5 months) exhibited larger, faster, and more frequent saccades than older infants.
- 11-month-olds demonstrated high scanning efficiency across all scenes, with enhanced efficiency for social and complex scenes.
Conclusions:
- Infant scanning efficiency undergoes significant developmental changes.
- Visual scanning patterns are influenced by both age and stimulus characteristics (content and complexity).
- Saccade and fixation metrics offer a sensitive measure of cognitive processing in infants.
Abstract:
Though previous work has examined infant attention across a variety of tasks, less is known about the individual saccades and fixations that make up each bout of attention, and how individual differences in saccade and fixation patterns (i.e., scanning efficiency) change with development, scene content and perceptual load. To address this, infants between the ages of 5 and 11 months were assessed longitudinally (Experiment 1) and cross-sectionally (Experiment 2). Scanning efficiency (fixation duration, saccade rate, saccade amplitude, and saccade velocity) was assessed while infants viewed six quasi-naturalistic scenes that varied in content (social or non-social) and scene complexity (3, 6 or 9 people/objects). Results from Experiment 1 revealed moderate to strong stability of individual differences in saccade rate, mean fixation duration, and saccade amplitude, and both experiments revealed 5-month-old infants to make larger, faster, and more frequent saccades than older infants. Scanning efficiency was assessed as the relation between fixation duration and saccade amplitude, and results revealed 11-month-olds to have high scanning efficiency across all scenes. However, scanning efficiency also varied with scene content, such that all infants showing higher scanning efficiency when viewing social scenes, and more complex scenes. These results suggest both developmental and stimulus-dependent changes in scanning efficiency, and further highlight the use of saccade and fixation metrics as a sensitive indicator of cognitive processing.
