How a third grader’s afternoon restlessness predicts their chances of finishing college

A recent study published in Developmental Psychology suggests that a child’s ability to control their physical movement tends to wear down as the school day progresses. This steady decline is linked to their long-term academic success. By tracking elementary students with wearable devices, researchers found that children who can sustain their behavioral control for longer periods tend to achieve more in high school and complete more years of education as adults.

Self-regulation is the ability to manage thoughts, emotions, and actions to fit the expectations of a specific environment. In a standard classroom setting, this might look like a student raising their hand to speak rather than shouting out an answer. It also involves staying seated during a lesson instead of wandering around the room.

“Being in the classroom requires some degree of self-control. Children are expected to walk instead of run, keep their hands to themselves, and stay in their seats when the situation requires,” says lead author Andrew E. Koepp, an assistant professor of applied psychology at New York University.

Controlling these natural impulses takes mental effort. Because managing behavior requires ongoing cognitive energy, a child’s capacity to regulate their actions might not be a fixed trait.

“Applying this self-control takes effort and by the final ring of the school bell, children have been doing it for hours,” Koepp says. As a result, this ability may change throughout the day as mental fatigue sets in.

Traditional tools for measuring behavior usually rely on adult observations or surveys conducted over several months. Sometimes researchers also use one-time laboratory tasks to test a child’s restraint. These methods make it difficult to observe how a student’s self-control might fluctuate from hour to hour in a natural school setting.

Adult observations can also introduce interpersonal biases. For example, a teacher’s subjective rating of a student might be influenced by a halo effect, where a generally positive impression colors their specific behavioral ratings. A continuous objective measurement tool helps avoid these human biases.

To overcome this measurement barrier, scientists can use wearable technology. Devices that track physical movement provide continuous naturalistic data about how active a child is during the day. This passive sensing happens in the background without interrupting the student’s normal routine.

Since regulating physical movement is a primary way young students are expected to show self-control, tracking gross motor activity offers a window into their behavioral endurance. The authors sought to understand if this physical self-regulation deteriorates across the typical school hours. They also wanted to see if individual differences in this daily behavioral stamina might predict a student’s educational success years into the future.

The authors analyzed data from a large national project that followed a group of children from birth to age 26. Their specific analytic sample included 747 participants. The demographic breakdown of the group was 49 percent female, 76 percent White, 13 percent Black, 6 percent Hispanic, and 5 percent other racial or ethnic backgrounds.

When these participants were in the third grade, they wore small devices called accelerometers around their waists for up to five school days. An accelerometer is a wearable sensor that measures the frequency and intensity of a person’s physical movement. The research team collected this continuous movement data for each hour between 9 a.m. and 3 p.m. to establish a timeline of behavior.

“We focused on third grade because it marks a transition to middle childhood and greater independent control of behavior,” the authors note in the study. This period represents an important phase when students generally stay in a single classroom rather than moving around for different subjects.

In addition to the movement tracking, teachers and trained classroom observers independently rated the children on hyperactive and disruptive behaviors. The children also completed standardized academic tests in the third grade to measure their learning in math and reading. Following up years later, the participants completed academic tests again at age 15.

When the participants reached 26 years of age, they reported the total number of years of education they had completed. The researchers also examined observational data of the participants’ mothers interacting with them during early childhood. These early assessments occurred at regular intervals from age six months up to four and a half years.

The data showed that, on average, a child’s physical activity levels tend to steadily increase as the school day progresses. The authors suggest this rising physical activity reflects a gradual decline in the students’ ability to regulate their behavior. As the hours pass, the mental effort required to sit still seems to deplete.

“Our findings imply that, behaviorally speaking, most children tend to ‘lose it’ a bit by the end of the school day,” notes Koepp. This physical restlessness appears to mirror mental exhaustion.

There were notable individual differences among the students. Some children showed much steeper daily increases in activity than others. Teachers and classroom observers rated the students who had the steepest activity increases as more impulsive and disruptive overall.

The scientists found that the rate at which a child’s activity increased across the day predicted their academic performance. Children who showed larger increases in physical movement from morning to afternoon tended to have lower academic test scores in the third grade. This suggests that the ability to sustain behavioral regulation is tied to a student’s capacity to engage with classroom learning.

“Interestingly, those who could ‘keep it together’ for longer tended to do better in school and were more likely to achieve educational success long-term,” says Koepp. The data highlighted a notable link to higher education.

This pattern had long-term implications. Lower academic achievement in the third grade provided a developmental pathway to lower test scores in high school. It also predicted fewer total years of education completed by the time the participants reached early adulthood. In fact, children with more self-control had 20 percent greater odds of completing a four-year degree.

The researchers also discovered links to the early childhood experiences of the participants. Mothers who provided more cognitive stimulation and showed higher sensitivity in the early years had children with better behavioral control in preschool.

In turn, that early self-control in preschool predicted smaller increases in physical activity across the third-grade school day. This sequence provides evidence for a developmental cascade where early positive parenting helps build the foundational skills needed for behavioral stamina in elementary school.

While the tracking devices offer an objective way to measure behavior, the authors point out a few limitations. The wearable sensors only capture physical movement, which means they do not measure how well a child regulates their emotions or their internal attention.

Readers should not misinterpret the findings to mean that all physical movement in the classroom is harmful. Physical activity can help children learn by allowing them to explore their environment or use gestures to express complex ideas. The type of movement captured by the waist-worn devices was mostly large bodily shifts that can disrupt traditional classroom tasks.

Another limitation involves the demographic makeup of the participants. The children in this study were born in 1991, and the group was predominantly White. The findings might not perfectly reflect the experiences of a more contemporary and diverse student population.

Future studies might look at how these patterns change as children grow older and their brain development advances. Older students generally become less active and typically develop stronger executive functions. Executive functions are the higher-level mental skills needed to plan ahead, focus attention, and meet goals.

“We know that self-control helps children ignore distractions and focus on learning. Our findings imply that self-control is not just a personality trait, but something that can wear out and also perhaps something that could be restored,” says Koepp.

The researchers suggest exploring specific parts of the school day that might help restore a child’s behavioral stamina. For instance, the data indicated brief shifts in activity around the lunch hour. This hints that a break for food and socializing might temporarily reset a student’s self-control.

“As a society, we should value activities like recess that could let children blow off some steam and potentially recover some of this self-control. It might even benefit their learning,” Koepp adds.

Scientists could also investigate whether a good night of sleep or a vigorous physical education class helps children maintain their focus later in the day. Identifying the daily routines that support behavioral regulation could provide educators with simple ways to improve classroom learning without requiring entirely new curricula.

Future research could also incorporate multiple types of wearable technology. Combining movement sensors with devices that track heart rate or eye movements could provide a much broader picture of how a student manages their arousal and attention. Such tools could help schools find ways to better accommodate movement while supporting student focus.

This research was supported by grants from the National Science Foundation and the National Institutes of Health. The study, “Keeping It Together: Hourly Dynamics of Children’s Behavioral Regulation at School in a Decades-Long Cohort Study,” was authored by Andrew E. Koepp, Elizabeth T. Gershoff, Deborah Lowe Vandell, Angela L. Duckworth, and Allyson P. Mackey.