Degrees of Constraint (DoC).

We are having the wrong argument about ADHD.

We keep asking

Is it real or

socially constructed,

genetic or

environmental,

overdiagnosed or

under-recognised.

All of those questions miss the point.

The real issue is not whether ADHD exists.
It does.
The issue is why more developing minds

are being pushed across the same clinical threshold,

without the genome changing.

To understand that,

we need to stop treating cognition like haemoglobin.

Haemoglobin is a low-plasticity system.

Its structure tightly specifies its function.

Cognition is nothing like this.

Cognition is a high-plasticity,

high-constraint-sensitive system

not a thing you have,

but a process that emerges

through development, inside limits.

I want to propose a way of thinking about this difference.

I call it Degrees of Constraint.

Treating cognition as if it were haemoglobin

That is the category error,

That sits underneath half our arguments about
ADHD, autism, and supposed “epidemics” of disorders.

When people argue about whether

ADHD is “real” or “socially constructed,”

they are arguing on the wrong axis.

The right axis is constraint.

Here is the model in one line:

Intrinsic Degrees of Constraint describe what biology allows;

Effective Degrees of Constraint describe what the environment allows you to achieve.

Haemoglobin is intrinsically low‑DoC:

structure tightly specifies function,

so, outcomes don’t vary much without breakdown.

Height sits higher.

It is polygenic and plastic.

Infection burden, nutrition, stress, and illness

during development all shift where you land.

However, in many societies,

these environmental constraints have been sufficiently reduced

that most people now exhibit performance closer to their developmental ceiling.

Height didn’t become Mendelian.

DoC collapsed because the environment became less negotiable.

Cognition is higher still.

The developing…