OUT of a standard Holyrood education committee sailed a piercing story the other day. A school teacher was giving testimony to an inquiry into the effect of poverty on children’s attainment.

Nancy Clunie, the head at Dalmarnock Primary School, noted at one point that some of her poorer pupils in Glasgow “had never seen the sea”.

This got to me like a tidal pull itself, deep and elemental. The economic deprivation it indicated was bad enough – some parents so skint they couldn’t amass the resources for a family trip to Largs or Ayr.

But the play deprivation was almost worse. I can’t imagine my own childhood, nor that of my own kids, without the experience of “plowtering” about on the beach. Even if it was only the occasional foray between squalls of summer rain on some Hebridean island.

I know that it’s installed in me a yearning towards the sea. I love how it produces the infinite randomness of a coastline. It helps me feel what it’s like to be actually on this planet, when you can see two of its great constituting elements meet and clash. The sea restores and detoxes me.

And for that I give gratitude to my family play experiences, as father and child. Left relatively alone to explore the beach (or the forest, let alone the city streets) the child feels that the world is theirs, that they belong in it – and that there is enough of it to be shared by everyone, freely and generously.

This is not a feeling to be underestimated, if we want our kids to be truly capable for the unstable, dynamic world we’re presenting them with. Indeed, it may be vital.

How do we make confident, happy, purposeful 21st-century kids? There is a quietly simmering debate about this in Scottish education at the moment. And the role of free, open and exuberant play, preferably in nature but also in the city, is at the heart of it.

This is the kind of debate you want to have in a progressive society – one between different positions among the undeniably well-meaning. But the differences are real.

On one side is the education secretary John Swinney, who is on a mission to close the attainment gap between rich and poor kids.

A key instrument in this is national tests for numeracy and literacy in Primary 1 classes, meaning ages 4-5.

The educational press is already full of stories about confused, complaining P1 kids, clicking through stories and multiple options on computer screens, listlessly dragging icons here and there.

On the other side, to my eyes at least, there is a very large and fearsomely well-researched constituency who thinks these tests are misguided at best, and positively harmful at worst. Citing research from institutions like the United Nations, Harvard and Stanford, they make strong claims.

Their most robust is that the “early years” of child development – generally regarded (and also by our Curriculum For Excellence) as stretching from 0 to 8 years – are best governed by essentially play-based practices (with literacy and numeracy skills tapering in towards the end).

Which is where sea, nature and neighbourhoods, with kids rolling, roaming and exploring around them, come into the picture.

No wonder five-year-olds are fidgeting away during these 50 minute tests, say play-advocates. The human sciences (neuropsychology in particular) are telling us they should instead be cavorting with their pals, doing fun and interesting stuff in open and stimulating places.

Why? Because play builds kids basic mental and emotional equipment – and playing doesn’t really complete that job until they are about seven or eight. So early testing distorts a naturally developing process.

This side of the argument usually has a slam-dunk for their case. They show how nations who run play-based kindergarten schemes to six or seven years score consistently well in global education charts.

The test-advocates often render the play-advocates as starry-eyed, romantic and idealist about kids’ play. They get particularly stern when they point to 15-month gaps in literacy and numeracy between young kids of different economic backgrounds.

Surely the best thing to do is to intervene on the “basics” as early as possible? Ensuring that education levels the playing field, even as it faces socio-economic inequalities it cannot control?

Yet if the science on early child development is correct, early exams on the three R’s are the cure that makes the disease worse.

Upstart Scotland’s #PlayNotTests campaign makes many brilliant points, but I think their best is on how play experiences help the “self-regulation” and “resilience” of children.

Upon these two qualities, much else in the educational process rests. And both are developed through play. We complex human animals have to figure out how to co-exist with other complex human animals – with all our capacities for love and hate, to tell truth and lies, and all the shades of emotion and reason in between.

Play is what nature has given us, particularly in early years, to safely rehearse living with others. The rough-and-tumble, the give-and-take of play experience helps us, in the words of neuroscientist Allan Schore, with our “affect-regulation”. This means our ability to control our emotions in reaction to our fellows.

So many “behaviour” problems identified with early learners – either overly rebellious, or anxiously conforming – are to do with a deficit in affect-regulation, which comes from a deficit in play experience. If you start school at five, it bites deep into that precious zone of development.

Play-forged kids will also be resilient – meaning able to bounce back much better from difficulties and challenges. In these pages a few months ago, John Swinney wrote with urgency about the Scottish Government’s commitment to reduce “Adverse Childhood Experiences” (or ACEs).

ACE is the new buzzword that emphasizes how reducing stressful or oppressive early experiences significantly improves children’s mental health, and personal prospects, in later life.

However the play-advocates are making it very clear. Starting formal school too early, and too uniformly, should be regarded as an “Adverse Childhood Experience”.

A US study noted that “disadvantaged children who were taught formally before the age of six were, by their late twenties, significantly more likely to have problems with relationships and difficulty in holding down jobs. They were also more likely to have been involved in crime and less likely to vote.”

It will be perhaps no surprise to discover that I am with the play-advocates. Full disclosure: I’m joining the board of Upstart Scotland, along with the ex-Children’s Commissioner Tam Baillie, the psychologist Carol Craig, and others.

The current Scottish Government inherited a cross-party policy consensus with the Curriculum For Excellence. One of its insights was to encourage play-based learning until the age of eight, as the bedrock beneath kids becoming “successful learners, confident individuals, responsible citizens and effective contributors”.

The Scottish Government, dealing with the usual contumely from the usual sources, must try to hold its nerve on this vision (or as these stress-inducing P1 tests bed in, perhaps regain it).

We should remember what holding our nerve feels like. Something like standing at one side of the rock pool, wondering whether a well-timed leap would get us to the other side. Nothing for it but to try.

For more visit www.upstart.scot