"They did it yesterday, so they can"

Here's the belief that turns a capacity question into a character one. He remembered the kit last week. He came off the tablet on Tuesday. So he can, and if he can and doesn't, that's a choice, and choices have names.

Yuko Munakata and colleagues, in 2012, described three transitions in how children develop what researchers call cognitive control, the ability to break out of a routine and do the thing that's needed rather than the thing that's habitual. The first is learning to override a habit at all, in response to a signal from outside. The second is a shift from what they called reactive control, engaging the effort in the moment when something prompts it, to proactive control, engaging it in advance, in preparation. The third is a shift from relying on signals in the environment to being self-directed. Children move through these gradually, and the later ones come well after the earlier.

Apply that to the kit. The week Sam remembered it, what happened? In my experience, when parents look, there was a cue. You said "kit" as he went upstairs. It was by the door because you'd moved it. He saw a classmate with theirs on the way in. That's reactive control, engaged by a signal, and a nine-year-old can often do it. What you're expecting on the other Thursdays is proactive, self-directed control, thinking of the kit in advance with nothing prompting him, and that's two transitions further along, and he isn't there, and the fact that he managed the cued version proves nothing about the uncued one. They're different abilities on different timetables.

So "he did it yesterday" is true and it doesn't mean what the standard takes it to mean. It means he can do it when cued. It doesn't mean he can do it alone, and the standard has been set at alone. A child who's able when reminded and unable when not isn't being inconsistent. They're at a stage, and the stage is a normal one, and the way through it isn't to remove the cues and wait for character to develop. It's to keep the cues and let the development happen underneath them, which is what chapter 20 calls the handover.

I'm reaching from a review of laboratory tasks to a Thursday morning, and I'll say so. But the shape of the finding is the thing. Cued before uncued, reactive before proactive, prompted before self-directed. Every parent who's noticed that their child can do it "when they want to" has noticed the gap between those, and named it wrongly.