A major challenge in developmental cognitive neuroscience is that preverbal infants cannot tell us what they perceive. This is especially difficult when studying conscious perception: how can we know whether an infant actually saw a stimulus, rather than merely processed it unconsciously?
In this study, led by François Leroy and Ghislaine Dehaene at NeuroSpin, Saclay, we investigated the attentional blink in 4-month-old infants. In adults, the attentional blink occurs when two targets are presented in rapid succession: if the second target appears too soon after the first, it is often missed. This phenomenon is thought to reflect a temporary bottleneck in conscious access, when the brain is still engaged in processing the first target and cannot yet make the second one available to a broader cognitive workspace.
Capitalizing on Event-Related Variability (ERV) techniques we introduced a few years ago, the study shows that a similar dynamic is already present in preverbal infants. Four-month-old infants can engage attention strongly enough in a visual task to block the perception of a subsequent stimulus. This challenges the idea that very young infants are merely passive observers of their environment. Instead, their brains already show structured temporal limits on attention and conscious access.
As previously mentioned, a particularly important aspect of the work is methodological. Because infants cannot verbally report whether they saw a stimulus, we used ERV methods, such Variability Quenching detection and flyby latency analyses, to examine how variable and structured the neural response is from one event to the next.
This is crucial because the difference between “seen” and “unseen” perception may not always appear as a simple increase or decrease in average activity. Instead, conscious access may be reflected in the dynamics and variability of the response: how consistently, richly, and flexibly the brain reacts to an event. ERV techniques therefore provide a way to infer, from neural dynamics alone, whether a stimulus likely reached awareness in a preverbal infant.
The broader message is that conscious perception in infancy can be studied without relying on verbal report. By combining the attentional blink paradigm with measures of event-by-event neural variability, the study offers a window onto the early development of attention, awareness, and access to a central cognitive workspace.
A useful way to summarize the contribution is: the paper does not only show that infants can experience an attentional blink; it also shows that detecting awareness in infants requires looking at the dynamics of single events, not only at average brain responses.
To know more:
- Leroy, F., Naik, S., Gulbinaite, R., Palu, M., Battaglia, D., & Dehaene-Lambertz, G. (2026). Dynamics of the attentional blink in preverbal infants. Proceedings of the National Academy of Sciences of the United States of America, 123, e2526752123. https://doi.org/10.1073/pnas.2526752123.