Related Experiment Video
Updated: Sep 23, 2026
Using Eye-tracking to Assess the Relative Importance of Visual and Vestibular Input to Subcortical Motion Processing in the Roll Plane
Published on: August 22, 2025
Motion processing asymmetries and stereopsis in infants
1Visual Development Unit, Department of Psychology, University College London, London WCIE 6BT, UK. j.wattam-bell@ucl.ac.uk
Insights
Infants show a preference for nasalward motion from 7 weeks old, independent of stereopsis development. This directional visual preference may originate in the infant brain's extrastriate visual cortex.
Area of Science:
- Developmental Psychology
- Neuroscience
- Vision Science
Background:
- Infant visual system development is complex.
- Understanding early visual processing aids in identifying developmental trajectories.
- Directional visual preferences in infants are not fully understood.
Purpose of the Study:
- To investigate directional motion preferences in 6-25-week-old infants.
- To determine if stereopsis onset influences directional visual preferences.
- To explore the neural origins of observed directional asymmetries.
Main Methods:
- Forced-choice preferential looking paradigm used.
- Monocular and binocular viewing conditions with moving random-dot patterns.
- Longitudinal testing incorporating stereopsis assessment.
Main Results:
- Infants preferred nasalward motion with monocular horizontal stimuli.
- No overall preference for vertical motion, but correlation with upward optokinetic nystagmus (OKN) bias.
- Directional preference emerged by 7-8 weeks and persisted; stereopsis onset did not affect it.
Conclusions:
- Infants exhibit distinct directional visual motion preferences early in development.
- These preferences are independent of stereopsis development.
- Asymmetries may reflect early activity in extrastriate visual cortex, such as area V5/MT.
Abstract:
These experiments used forced-choice preferential looking to test infants for preferences between pairs of random-dot patterns that moved in opposite directions. With monocularly-viewed horizontally moving patterns, 6-12-week-old infants showed a preference for nasalwards motion. With binocularly-viewed vertical motion, there was no overall preference, but the results did show a significant correlation between upwards bias of OKN and preference for downwards motion. In a longitudinal experiment, the nasalwards preference first appeared at 7-8 weeks, and thereafter persisted until the end of testing (23-25 weeks). In this experiment the infants were also tested for stereopsis, under conditions that were as nearly as possible identical to the direction preference test. There was no evidence that the onset of stereopsis had any effect on the directional asymmetry. The directional asymmetries revealed by these experiments appear to be distinct from the asymmetries of OKN and motion VEPs. It is possible that they reflect asymmetrical directional responses in extrastriate visual cortex (e.g. area V5/MT).
