A new longitudinal analysis of UK cohort data finds that children who test as “bright” at age five but grow up in low‑income families maintain academic parity with richer peers through primary school, only to experience a marked drop in school engagement, behaviour, mental health and exam outcomes during the move to secondary school between about ages 11 and 14. The paper — based on the Millennium Cohort Study and reported in a working paper and later published in Research in Social Stratification and Mobility — shows large gaps by the end of compulsory schooling: bright children from poor homes are roughly 26 percentage points less likely to secure top maths GCSE grades and about 21 points less likely to secure top English grades than equivalently high‑scoring peers from the richest families, after statistical adjustments link to working paper/summary and link to journal listing. For Thai educators and policymakers watching aspirations and social mobility, the study raises a clear alarm: early talent alone is not enough; the school transition matters, and social disadvantage can erode promise during early adolescence.
The finding matters because it challenges a hopeful interpretation of early test scores. If high cognitive potential at age five normally guaranteed later success regardless of background, then policies might focus mainly on early identification. Instead, the new evidence suggests that advantages and disadvantages reassert themselves at a later developmental hinge point — the shift from primary to lower secondary school — when social context, peer groups and institutional support (or its absence) can magnify inequality. The research draws on the UK’s Millennium Cohort Study, a nationally representative longitudinal survey of children born in the UK in 2000–02 that has followed nearly 19,000 young people from infancy into their late teens Millennium Cohort Study background.
Key facts from the analysis are striking and statistically robust within the limits of available data. The researchers identified the top quarter of performers on age‑5 cognitive assessments as “high‑achievers.” Within that subgroup the analytic sample included about 1,392 children from high‑income backgrounds and 389 children from low‑income homes as classified at age five; those small numbers for the disadvantaged but high‑ability group are one limitation the authors acknowledge summary and sample details and author blog summary. Up to the end of primary schooling, cognitive test scores and basic school engagement measures for bright children were broadly comparable across income groups. But between approximately ages 11 and 14 — the United Kingdom’s Key Stage 3 and the common transition to secondary education — the disadvantaged high‑achievers showed a particularly sharp relative decline in attitudes to school (lower value placed on hard work), more behavioural problems, worse mental‑health indicators, and weaker exam outcomes by the time of GCSEs (taken around age 16). The authors estimate a 26 percentage‑point shortfall in top maths grades and a 21‑point shortfall in top English grades when comparing bright children from the poorest and richest backgrounds detailed findings and figures.
Several mechanisms are consistent with the pattern and are suggested by complementary research on adolescence, school transitions and inequality. The secondary‑school transition brings multiple simultaneous changes: new schools, larger year groups, different teacher–pupil relationships, more complex organisation, and new peer networks. International reviews and cohort studies show this period is one of elevated risk for declines in school engagement and for worsening mental health for some pupils, with the social status of pupils within their school’s socioeconomic mix influencing wellbeing and behaviour Institute of Health Equity review on transitions and empirical papers documenting declines around the primary–secondary change trajectories of mental health research summary and UK evidence on worries about the transition PMC article on transition worries. For a child whose cognitive ability was clear at age five but whose family lacks economic and cultural resources, the arrival at secondary school can coincide with fewer out‑of‑school learning supports, reduced access to private tuition or enrichment, increased exposure to risky peer influences, and a school environment in which social comparisons and subtle exclusion can undermine motivation.
The study authors — who frame the question around social mobility — conclude that “the failure to fully capitalize on the early potential of this group [bright children from poor families] is likely to be a key reason why the UK is failing to become a more socially fluid society” direct author conclusion as reported. That interpretation privileges the role of environment and schooling over an assumption that early cognitive advantage inexorably translates into later advantage. But the authors and commentators are careful to note limits: the subgroup of bright disadvantaged children is relatively small in the cohort, measurement of “ability” at ages 3–5 has noise, and findings are observational (associations with timing and outcomes do not prove simple causal chains). The paper therefore offers an empirically grounded alarm rather than a final causal verdict; it identifies when and for whom policymakers should intervene.
Thailand readers will see clear parallels. The Thai basic education structure — six years of primary (Prathom 1–6, roughly ages 6–11) followed by lower secondary (Matthayom 1–3, ages 12–14) and upper secondary (Matthayom 4–6, ages 15–17) — places the primary–secondary transition at the same early‑adolescent period identified in the UK study Thailand education system overview and Ministry of Education basic education outline (Thai source). Thai families and schools also confront stark resource disparities: children in well‑resourced Bangkok international or private schools typically have easy access to tutoring, enrichment and smaller classes, while learners in some rural provinces and urban low‑income areas may rely on crowded classrooms, limited extra‑curricular options and family incomes that make private after‑school support unfeasible. That gap manifests in the thriving “shadow education” market in Thailand — private tutoring and cram schools that parents invest in heavily, particularly when stakes are high for entrance examinations and university placement studies on shadow education in Thailand and research on private tutoring prevalence and policy debate. Put simply: bright children from poorer Thai homes may display early promise, but if the Thai pattern mirrors the UK evidence, that promise is at risk when schooling becomes more demanding socially and academically.
What should schools, parents and policymakers do? The research points to several practical entry points, supported by international evidence on transition support. First, strengthening transitional support when children move to Matthayom 1 is critical: systematic induction programmes that familiarise pupils with new teachers and routines, targeted pastoral care, and peer‑mentoring from older students reduce anxiety and increase belonging (policy recommendations collated in the Institute of Health Equity report) transitions and health equity guidance. Second, targeted academic support for initially high‑ability but low‑income students — not only in the earliest years but during Key Stage 3 / Matthayom 1–3 — can prevent gaps widening; that includes in‑school booster classes, subsidised tutoring for disadvantaged pupils, and curriculum differentiation that keeps bright students engaged while they face new academic structures. Third, mental‑health and behaviour interventions matter: school counsellors, social‑emotional learning curricula, and programmes that mitigate the negative consequences of sudden social reordering at adolescence can protect engagement and attainment evidence on SEL and transition support. Fourth, monitoring and data collection must track not only test scores but measures of engagement, wellbeing, and behaviour to spot early divergence before exam years.
Thailand already has some of the policy levers needed — a strong culture that values education, extensive private tutoring infrastructure, and decentralised school networks — but that combination can cut both ways. Private tutoring can help bright disadvantaged pupils catch up academically, but it is often unregulated, expensive and unevenly distributed, and can deepen inequalities if better‑off families buy more hours of instruction. Thai policymakers could consider targeted subsidies or voucher schemes for tutoring aimed at academically promising low‑income students during the Matthayom 1–3 window, coupled with in‑school mentoring and mental‑health services funded to reach poorer districts. Schools can also adopt transition‑focused practices: structured orientation weeks, smaller pastoral tutor groups, and explicit attention to peer inclusion for newly arrived students from different socioeconomic backgrounds.
Historical and cultural context helps explain why this question resonates strongly in Thailand. Thai parents traditionally equate educational success with social mobility and family honour, investing heavily in extra lessons and long study hours. The intense focus on top exam performance (from O‑Net to university entrance) can create a tunnel vision where the social and emotional needs of adolescents receive less attention. The UK study’s implication — that early cognitive promise is necessary but not sufficient — should remind Thai education stakeholders that durable progress requires sustained supports through adolescence, not only early childhood investment. Culturally‑appropriate mentoring (for example linking bright disadvantaged children with older “role models” from similar backgrounds who succeeded) and community‑led enrichment activities that draw on local culture and values may be particularly effective in Thai provinces where formal resources are scarce.
Balanced perspectives are important. The UK paper’s strengths include long‑run, population‑level data and careful statistical controls; its limits include small subgroup sizes for disadvantaged bright children, potential measurement error in early tests, and the observational nature of the findings. The patterns observed in the UK may differ in degree and mechanism in other countries because education systems, the prevalence and cost of tutoring, school organisation, and social norms vary. For example, the structure and intensity of “shadow education” in Thailand — and its role in sustaining high achievement for some disadvantaged but driven pupils — could lead to different outcomes than in the UK. Conversely, where local schools are under‑resourced and adolescent mental‑health services are limited, the Thai experience could be even more stark. International evidence on transitions and mental health suggests that the early secondary years are a universal stress point and an efficient policy target, but local research is needed to design and evaluate precise interventions review of transition interventions.
Looking ahead, several research and policy directions follow from this work. Researchers should replicate the UK analysis in different national settings (including Thailand) using cohort or administrative data to see whether the same pattern — parity through primary years followed by divergence in early secondary — holds. Within countries, studies should disaggregate by gender and ethnicity, and investigate interactions with other vulnerabilities (disability, migration background, rurality). For policymakers, the immediate priority is acting on the modal finding: provide sustained, targeted supports for promising children from low‑income homes during the early secondary years. That means funding pastoral care and school counselling, ensuring equitable access to catch‑up and stretch programmes, and supporting social‑emotional learning and positive peer cultures during Matthayom 1–3.
For Thai parents and teachers reading this, practical steps matter. Parents of promising young children should maintain academic enrichment after primary school even if school becomes bigger and more bureaucratic; that could mean low‑cost local tutoring, online resources, or volunteering time to supervise study. Teachers should be alert to declines in motivation among capable pupils who may become disengaged when they reach lower secondary; early conversations, small‑group mentoring, and linking schoolwork to future goals can help. Schools and local educational authorities should prioritise transition programmes, embed counselling services or referral pathways, and keep records that track engagement and wellbeing as well as examination performance.
The UK study’s headline message is both simple and consequential: spotting talent at age five is important, but sustaining it through the turbulent early teen years is the policy challenge that determines whether promise translates into top exam results and, ultimately, social mobility. For Thailand — a country where family expectations and private tutoring are already central to the education landscape and where the move to Matthayom 1 happens at a similar biological and social junction — the lesson is clear. Policies that combine academic support with social‑emotional and behavioural supports during the school transition offer the best hope for converting early potential into later success.
Sources: the PsyPost summary of the paper PsyPost report; John Jerrim’s working‑paper summary and data discussion FFT Education Datalab summary; the preprint and project page OSF preprint; journal listing in Research in Social Stratification and Mobility ScienceDirect volume; background on the Millennium Cohort Study CLS overview; evidence on school transitions, wellbeing and inequality Institute of Health Equity transitions report and research on adolescent mental‑health trajectories ACAMH article; and context on Thailand’s education structure and shadow education Education in Thailand overview and studies of private tutoring in Thailand shadow education research.