Two-year-old Henry is fully absorbed by the iPad in front of him. Every time a smiley face appears, he taps the screen, transforming it into a cartoon of a dancing animal. Although this seems like a simple, repetitive game, it’s actually an important test for a crucial cognitive skill in his developing brain. Henry wears a cap equipped with sensors connected to an analytical machine that monitors his brain activity. As he plays, the cap is mapping his decision-making abilities, measuring a skill known as inhibitory control.

This task is part of a larger research project led by the University of Bristol, aimed at understanding when young children develop the key abilities that help them focus and learn. While scientists know these skills are vital, they are still working to pinpoint exactly when they emerge in a child's brain.

The study follows the development of hundreds of children, ranging from six months to five years old, to track their progress in acquiring essential skills that influence their academic and social growth. What makes this research particularly unique is its connection to another long-term project. The mothers of 300 children in the study have been part of a health monitoring project since the 1990s, giving researchers an unprecedented wealth of data about the health, experiences, and genetics of both parents and their children. This rich context makes the study of child development truly one of a kind, according to lead researcher Dr. Karla Holmboe.

"We need to understand when different skills develop and how individual children progress over time," says Dr. Holmboe. "Children who struggle when they start school are likely to continue facing challenges, and this can affect them into adulthood. By understanding these early stages of development, we can better support children at a much younger age."

Throughout the study, children and their parents visit the university’s psychology lab to engage in games that assess their brain activity. MRI scans are taken at key developmental stages—six months, three years, and five years—to capture a comprehensive picture of their brain development.

In one test, Henry plays the smiley face game, which challenges him to adapt his behavior. The face, initially appearing only on the right side of the screen, begins to appear randomly on the left as well. The goal is to see if Henry can resist tapping the right side out of habit and instead focus on the changing position of the smiley face.

"This is about testing whether Henry can adjust his attention," explains research assistant Carmel Brough. "In real life, this ability is important for children when they need to focus in school."

Dr. Holmboe further emphasizes that inhibitory control, such as stopping old habits to focus on new tasks, is crucial for school success. In another room, two-year-old Jackson is playing a game that tests his working memory. After observing a research assistant place stickers in various pots, Jackson is asked to recall which pots have stickers and which do not. The motivation? He gets to keep any stickers he finds.

"Working memory is a fundamental skill for solving problems, like remembering where you put something or solving a puzzle," explains Dr. Holmboe. "For young children, this ability is essential for learning math or reading."

The study also evaluates language development and processing speed, key indicators of how quickly children absorb new information.