In his National Day Rally speech, Prime Minister Lee Hsien Loong highlighted the Government's commitment to enhance pre-school education. It is indeed timely for Singapore to extend its focus to pre-school education, given research on the positive impact of early childhood experiences on life outcomes. Access to pre-school education also boosts social mobility, as many commentators have noted.

One area of concern, however, is whether some Singaporean parents might respond by doing more to ensure their children remain competitive to achieve constant upward mobility, or at least retain their family's place in the upper rungs of the income distribution.

According to this logic, if universal pre-school education is likely, then the demand for differentiation would rise accordingly. Some parents may focus on helping their children obtain Primary 1 competencies much earlier - a poll by The Straits Times and research firm Nexus Link in 2015 found that four in 10 parents sent their pre-school children to tuition.

As access to pre-school expands, more parents may feel the need to not just ensure their child goes to a "better" pre-school, but fill their offspring's schedules with enrichment lessons. Educational entrepreneurs are unlikely to pass up an opportunity to create services tapping wealthier parents' fears of their children losing their privileged position.

Research also suggests that children from disadvantaged families are actually the largest beneficiaries of pre-school when it comes to academic outcomes, and that the academic gains for those from better-off backgrounds may be minimal. So over-anxious parents should be reminded that hot-housing one's pre-school children in an attempt to build their academic competencies may thus come to naught.

A nationally representative 2012 study by University of Texas psychologist Elliot Tucker-Drob of 1,200 children in the United States found that there were no differences in reading and mathematics test scores for children raised in wealthier homes who went to pre-school and those who did not. For children in disadvantaged homes, test scores were much higher if they went to pre-school than if they stayed home.

Pre-school, in other words, provides a setting for learning foundational competencies that children from disadvantaged families might not otherwise be able to access.

Those from wealthier and more educated backgrounds, in contrast, already benefit from the stimulating environment their parents are able to provide at home.

Rather, the gains that children from better-off backgrounds accrue from pre-schools may be more socio-emotional. In pre-schools, they have opportunities to learn how to share toys and accepting how to win and lose in games. Ideally, they would also interact with others from different socio-economic, ethnic and religious backgrounds.

With the added government investment in developing Singapore's pre-school sector, especially teachers' competencies through providing national training opportunities akin to the rest of the school system, hopefully more parents will be secure that the quality of the typical pre-school is more than adequate.

This is already true for primary schools: a recent nationally representative survey by the Institute of Policy Studies of 1,500 parents with primary school children found that over 80 per cent of parents reported that the school their child attends is a good school.

What's next? While pre-school matters, research is also consistent that at least some child outcomes are related to their home experience. Parental attention and interaction through play and reading with their child are just some of the ways that children become equipped for their lifelong learning journey.

Unfortunately, parenting styles differ. Parents who struggle financially, with health issues, disability or marital disruptions, will find it a challenge to ensure a conducive environment for successful childhood development.

This then calls for focused state and community intervention. PM Lee's statement about the possibility of expanding KidStart, a programme that provides targeted attention to low-income and vulnerable parents and their children as early as possible, coaching them on parenting matters and ensuring adequate nutritional and healthcare access, is certainly heartening.

We need to do all we can to ensure that social mobility is sustained, that every child's outcomes are determined not by which income bracket they are born into, but by how well they seize the opportunities that all of them would be afforded.

• Dr Mathew Mathews is a senior research fellow and Mr Leonard Lim is a research associate at the Institute of Policy Studies, National University of Singapore.