Question it consciously#

Getting an assumption into the open is half the battle. The other half is deciding what to do with it. Once you have caught yourself making one — “the tank’s got enough,” “I already know this chapter,” “they’ll have covered that in the prerequisite” — you need a quick, repeatable way to weigh it rather than just nodding it through.

I use a three-step prompt I call ACT: Assumption, Contingency, Test. It’s a memory hook, not a magic formula. What it’s really doing is borrowing the move at the centre of cognitive behaviour therapy: notice the automatic thought, question it against the evidence, and — where it matters — test it in the real world rather than accepting it at face value (Beck, 2011). That notice-question-test pattern is one of the most thoroughly studied tools in clinical psychology, and you can run a lightweight version of it on yourself in about ten seconds.

The three steps#

Assumption — name it as one. When ACT fires, follow the thought with a flat statement: “That’s an assumption, so I ACT on it.” This sounds trivial, but it does real work. Until you label a thought as an assumption, your mind treats it as a fact and won’t argue with it. Naming it strips off the “fact” badge and makes it fair game for questioning. This is exactly the first step CBT teaches — catching the automatic thought before it drives your behaviour unexamined.
Contingency — what does it cost if you’re wrong? Picture the top two or three worst cases. If the downside is serious — running out of fuel, missing a deadline that can’t move, walking into an exam half-prepared — slow down and weight the next step heavily. If the worst case is that you turn up ten minutes late, you can afford to let it ride. This is the real filter: most assumptions aren’t worth the effort of testing, and pretending otherwise just turns you into someone who second-guesses everything. Spend your scrutiny where the impact earns it.
Test — what would actually settle it? Name one or two checks you could do, now or later, that would confirm or kill the assumption. Glance at the fuel gauge. Skim the chapter’s self-test questions before deciding you know it. Email the person instead of assuming they got the message. A test turns a vague worry into a decision point: if the check comes back bad, here’s the contingency I switch to. In CBT terms this is the behavioural experiment — the step where you stop arguing in your head and let reality answer.

Why this works (and where it stops)#

The reason questioning assumptions pays off is that a lot of our thinking runs on fast, automatic shortcuts that never reach conscious scrutiny (Kahneman, 2011). Those shortcuts are usually fine — they’re what let you start the car without inspecting the engine. But the same automatic machinery quietly generates the limiting assumptions too: “I’m no good at maths,” “it’s too late to learn an instrument,” “I’ll never get through this much material.” Catching and examining unhelpful automatic thoughts is the core, evidence-supported ingredient of CBT (Clark & Beck, 2010), and the everyday spin-off is simply this: the assumptions you say out loud and test are far easier to correct than the ones you never noticed you were holding.

Two caveats so you don’t oversell it to yourself:

ACT is a habit, not a therapy. The mnemonic borrows CBT’s questioning move, but a memory hook for everyday decisions is not the same as a course of cognitive behaviour therapy delivered by a clinician — and it’s worth knowing that “ACT” in psychology usually means something else entirely (Acceptance and Commitment Therapy). If anxious or intrusive thoughts are genuinely interfering with your life, the structured clinical version, not a tidy acronym, is what the evidence backs.
Don’t test everything. The contingency step exists precisely so you can let the trivial stuff go. Questioning every assumption is its own failure mode — slow, exhausting, and no safer than the person who questions nothing. The skill is calibration: heavy scrutiny where being wrong is expensive, a quick pass everywhere else.

Run ACT a few dozen times on real decisions and it stops feeling like a checklist. You start to feel the little click when a thought is an assumption rather than a fact — and that quiet click, more than the acronym, is the thing worth building.