Third-Graders’ Afternoon Restlessness Linked to Long-Term Academic Success

A longitudinal investigation published in *Developmental Psychology* examined how third-grade students’ ability to regulate physical movement changes across a typical school day and how this pattern predicts later educational outcomes. Using waist-worn accelerometers, researchers recorded hourly activity from 9 a.m. to 3 p.m. and found that, on average, children’s movement increased as the day progressed, indicating a decline in behavioral self-control. Participants who showed smaller increases in activity—i.e., who maintained steadier self-regulation—earned higher test scores in third grade, performed better on high-school assessments, and were more likely to complete a four-year college degree.

Psypost

The analytic sample comprised 747 individuals drawn from a national birth cohort (born 1991). Demographics were 49 % female, 76 % White, 13 % Black, 6 % Hispanic, and 5 % other. In third grade, each child wore an accelerometer for up to five school days, generating continuous movement data for each hour. Teachers and trained observers also rated hyperactive and disruptive behaviors, and children completed standardized math and reading tests. Follow-up assessments occurred at age 15 (academic tests) and age 26 (self-reported years of education). Statistical models linked the slope of hourly activity increase to both immediate academic performance and long-term educational attainment, revealing a 20 % higher odds of completing a four-year degree for children with stronger self-control.

Psypost

The study identified a cascade: early parental cognitive stimulation and sensitivity predicted better preschool self-control, which in turn forecasted smaller activity increases during third-grade school days. This sustained regulation was associated with higher academic achievement and greater educational persistence into adulthood. The findings suggest that behavioral stamina in elementary classrooms may be a measurable precursor to later academic trajectories.

Psypost

Lead author Andrew E. Koepp emphasized that self-control is a dynamic capacity that can diminish with mental fatigue and potentially be restored through targeted interventions. The research team highlighted the value of brief breaks—such as lunch periods—and recess as possible mechanisms to reset behavioral stamina. Funding for the project was provided by the National Science Foundation and the National Institutes of Health.

Psypost

The authors noted that accelerometers capture only gross motor movement, omitting internal emotional regulation and attentional processes. The cohort’s age and racial composition (predominantly White, born in the early 1990s) may limit generalizability to contemporary, more diverse student populations. Additionally, the observational design cannot establish causal effects of specific classroom practices.

Psypost

While the study links physical restlessness to academic outcomes, it does not address how other factors—such as sleep quality, physical-education intensity, or classroom instructional styles—interact with self-regulation. Direct measurement of physiological arousal (e.g., heart rate) or eye-tracking data could clarify these relationships.

Psypost

• “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.” — Andrew E. Koepp, Assistant Professor of Applied Psychology, NYU

Psypost

• “Applying this self-control takes effort and by the final ring of the school bell, children have been doing it for hours.” — Andrew E. Koepp

Psypost

• “We focused on third grade because it marks a transition to middle childhood and greater independent control of behavior.” — Andrew E. Koepp

Psypost

• “Our findings imply that, behaviorally speaking, most children tend to ‘lose it’ a bit by the end of the school day.” — Andrew E. Koepp

Psypost

• “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.” — Andrew E. Koepp

Psypost

• “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.” — Andrew E. Koepp

Psypost

The authors propose integrating movement sensors with heart-rate monitors and eye-tracking devices to capture a broader spectrum of arousal and attention. Subsequent studies should examine diverse, contemporary cohorts and test interventions such as structured recess, sleep hygiene programs, and varied physical-education curricula to determine their efficacy in sustaining behavioral regulation throughout the school day.

Psypost