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The cognitive neuroscientist exploring differences in children’s development

Published: 30 April 2026

Interviews Development Learning & Education Society Neuroscience Diversity Individual differences Learning environments Teaching methods Learning variability

Nicholas Judd examines how children’s environments shape brain development and learning 

Image by Claudia Flandoli for BOLD

Interviewee:

Nicholas Judd

Principal Investigator, Department of Psychology, Stockholm University

Interview by:

Aisha Schnellmann

Editorial Team, BOLD

Children grow up in very different environments that shape their development. In an effort to improve education and policy, Nicholas Judd examines how these differences affect learning and brain development. Aisha Schnellmann finds out more.

Aisha Schnellmann: What are you studying, and why? 
Nicholas Judd: Childhood and adolescence are periods of intense change, in children’s environments and in their brains. As children move through school, form new relationships, and encounter new learning experiences, their highly flexible brains adapt continuously. Different environments can either support, or hinder, brain development and the development of cognitive abilities such as reasoning and memory.

“As children move through school, form new relationships, and encounter new learning experiences, their highly flexible brains adapt continuously.”

My research focuses on understanding how differences in children’s environments shape cognitive and neural development. In particular, I study how inequalities in parental resources relate to differences in children’s brains and their cognitive abilities. Crucially, early-life differences tend to persist, manifesting as later-life disparities in health, wealth, and life satisfaction. I want to identify the environmental factors that drive these differences, so that we can build more effective interventions to improve children’s outcomes early on and in the long term.  

AS: What changes have you seen in cognitive development research over time?
NJ: We are becoming more of a ‘science’ in the traditional sense, as our results are increasingly replicable and able to show causal links. Isolating environmental factors in children is particularly challenging, however, since we cannot – for ethical and practical reasons – use many standard experimental tools such as randomization. For example, it would be neither possible nor ethical, when studying the effect of schooling on intelligence, to randomly assign some children to attend school and the others to receive no schooling.

Researchers have therefore become more creative in identifying natural experiments to study cause and effect. Cut-off dates for school entry are a good example of such a natural experiment; children are assigned to grades based on when they are born, which creates a form of natural randomization. Using this method, I have shown that schooling leads to improvements in intelligence – yet surprisingly, it does not appear to protect against aging of the brain in later adulthood.

This work has only been possible because of large, collaborative scientific cohorts and lots of children’s data; the growing democratization of science has also had a positive effect. While challenges remain, things seem to be moving in the right direction. Within the last decade, barriers to entry have been broken down through open access to publishing, code and data. New initiatives and increased government funding have helped to bring people of different backgrounds into science. We can expect progress in the field to accelerate, leading to many exciting findings.

“Pollution from a wildfire in California can travel across the United States and impact children as far away as Maine.”

AS: How will your research help children?
NJ: To take one example, climate change has made wildfires much more prevalent, and their effects extend well beyond the immediate areas in which they occur. Pollution from a wildfire in California can travel across the United States and impact children as far away as Maine. My work shows that repeated exposure to wildfire-related air pollution during childhood has harmful effects on brain development and cognitive abilities in adolescence.

These findings show the importance of reducing air pollution – whether from wildfires, factories or cars – through informed and effective public policy. By identifying how environmental exposures affect children’s development, my work generates evidence that can guide such decisions.  

I am also working directly to help children thrive today. I am building and testing a math learning intervention involving thousands of children, and have found that improving spatial abilities supports children’s math learning. We hope to release an open version of this learning platform soon to reach even more children.

“Every child is unique. Two children may respond positively to the same intervention but for entirely different reasons.”

AS: What are the biggest mysteries in this field?
NJ: Why are many environmental influences on children’s development so difficult to identify, and why do they affect children so differently? Why do so many educational interventions show promise in small studies but prove ineffective when scaled up?

The answer to both questions lies in children’s individual characteristics. Every child is unique. Two children may respond positively to the same intervention but for entirely different reasons, while two others may show little or no benefit for an equally large number of different reasons. Understanding these differences is key to explaining the remarkable diversity we see in development.

We need these fundamental insights into individual differences if we are to develop interventions that are both effective and scalable, and that meaningfully improve children’s outcomes.

AS: What are your hopes for the future in this field?
NJ: I hope we will make progress in identifying the child-specific characteristics and environments that shape development. Once we understand why children are at a certain point in their development, we can work towards individualized learning. This would drastically increase the likelihood that interventions will be effective, because it makes it possible to tailor them to a child’s background, interests, and learning needs.

Such insights could also help teachers by showing them where and when to intervene. This is best accomplished through multidisciplinary collaboration, broad research lines, open science, and sustained investment in the field. Once we gain a better understanding of how child-specific environmental influences shape individual pathways, we will be able to unlock the mystery of childhood development.

We need these fundamental insights into individual differences if we are to develop interventions that are both effective and scalable, and that meaningfully improve children’s outcomes.