Common Sense Test

This is the awkward question for any test with this name, and it comes first because everything else rests on it. Common sense is the phrase people reach for when they want their own view to sound obvious. A page that marked answers on that basis would be marking agreement with whoever wrote it.

So no item here is settled by opinion. Each one rests on a physical consequence, on arithmetic you can redo, or on a step the rest of a job waits on. The reason is printed under the answer every time.

That rules out a whole family of questions people expect on a page like this. Nothing asks what a sensible person would say to a rude neighbour, or how you should split a bill. Those have answers that change with who is asking, and a mark on them would be worthless.

It also means you can argue with the page. If a reason does not hold up, the item is wrong rather than you, and the reason is right there to check.

The pool is split evenly into three families, and a run draws the same number from each. That is what makes the three figures on your result card worth comparing with one another.

• What happens next. A candle in a sealed jar, a fridge door left open, salt on an icy path. The answer follows from how heat, air and water behave.
• Roughly how much. A litre of water, a walk of one kilometre, a bath run for a soak. The answer is a measurement or a sum, and the four options are far enough apart that a rough figure is enough.
• What comes first. A four step job with one step the other three depend on. Turn the water off before you open the tap.

Two different things wear the name, and they behave differently. One is knowing a fact about how the world works. The other is stopping long enough to use a fact you already had.

Rozenblit and Keil measured the first one in an unusually direct way. People rate their understanding of an everyday object highly, then try to explain how it actually works, then rate themselves again. The second rating is much lower. Confidence about everyday machinery runs well ahead of knowledge of it.

McCloskey found something similar about moving objects. Adults who had studied physics still held confident and wrong beliefs about the path a ball takes when it leaves a curved tube. Common is not the same as correct, and a belief can be widely held and still fail the first time you test it.

That is worth being plain about, because it changes what a low score means. Most wrong answers here are a fact somebody never happened to be shown, not a failure of judgement.

The score belongs to the items rather than to you. Swap thirty questions for thirty different ones and the number moves, so a percentile would describe this question set and pretend to describe a person.

There is a real research literature on practical judgement, and none of it fits. Wagner and Sternberg scored tacit knowledge inside single professions, against the answers experienced people in that job agreed on. That is a useful measure of one trade, and it is not a curve of correct answers on a general item set.

So this page shows your figure and ranks nobody against it. What it can give you is the arithmetic. There are four answers to every question, so answering at random scores about 25 per cent over a long enough run.

For a comparison that does hold up, what counts as a good digit span has one. That is a single task, measured the same way on thousands of people, and a percentile there means what it appears to mean.

There are thirty items in the pool. A run of eighteen uses more than half of them, so a second attempt repeats most of the questions you have already seen.

That makes the rise on run two easy to explain. You are remembering these particular questions. That is a real skill, and it is not what this page set out to measure. The first run is the one worth keeping.

Marking after each question does not change that arithmetic. Items are independent, so learning why a wet towel dries faster in a breeze tells you nothing about how many teaspoons make a tablespoon. Feedback is there because the reason is the useful part, not because it makes the test easier.

The same argument gets made about a much older number in the piece on what a good reaction time is. Practice moves a score, and what it moves is your familiarity with that exact task.

It is not a measure of intelligence, and this page will not describe it as one. Nothing here has been checked against any measure of intelligence, so any claim in that direction would be invented.

It is not a verdict on how you handle real life either. These are thirty questions in a browser, and nobody has shown that answering them predicts anything at all outside the page.

It is not a screening test. If something has genuinely changed in how you think, remember or make decisions, that belongs with a doctor rather than with a web page.

What a wrong answer usually means is narrower and more useful. You had not come across that particular fact. Reading the reason closes that one gap, and no other.