What a syllogisms test actually measures
A syllogism is the oldest formal shape in logic: two premises and a conclusion drawn from them. "All the files in the red box are encrypted; some files in the red box are older than ten years; therefore some encrypted files are older than ten years." Either the conclusion is forced by the premises or it is not, and that question has a single answer regardless of what anyone believes about files, boxes or encryption. Testing your reasoning this way strips away everything except structure, which is why syllogisms have survived two thousand years of curriculum reform and still appear in graduate admission tests, police selection batteries and law school entrance exams.
What the format measures is not knowledge and not vocabulary. It measures whether you can hold a set of stated constraints in mind, ignore everything you happen to know about the subject matter, and read off exactly what those constraints permit. That skill turns out to predict how well people handle contracts, medical guidelines, code branching and legal argument, because all of those punish the same error: quietly importing an assumption that nobody actually stated.
How the items on this page are built
Each of the eighteen items was written from a specific logical form rather than assembled from a question bank. The set covers universal and particular statements (all, some, no, some are not), conditionals with their two classic traps, exclusive and inclusive disjunction, and the awkward word "only", which reverses the direction of a claim in a way that catches almost everybody at least once. Roughly half the arguments are valid and half are not, so guessing one category throughout gets you nowhere near a good score.
Where an item asks you to judge a stated conclusion, there are three verdicts available: it follows necessarily, it does not follow but could still happen to be true, or it is ruled out entirely by the premises. That third option matters. Beginners collapse "does not follow" and "must be false" into one category, and the distinction between them is the single most useful thing this test can teach you. Other items instead give you four candidate conclusions and ask which one the premises actually support.
Belief bias, and why some conclusions here sound wrong
The best documented failure in this whole area is belief bias: people accept an invalid argument when its conclusion matches what they already think, and reject a valid argument when its conclusion sounds absurd. It is not a matter of carelessness. Under time pressure the brain checks the conclusion for plausibility first and only inspects the argument if that check fails, which is an efficient policy in daily life and a disastrous one on a logic test.
Several items here are constructed specifically to expose that shortcut. You will meet an argument whose premises force you to conclude that the lettuce in tray four is poisonous, and another whose conclusion — that every doctor in the hospital is careful — is entirely believable and entirely unsupported. Validity is about what the premises guarantee. A valid argument with a false premise produces a false conclusion perfectly correctly, and an invalid argument can land on a true conclusion by luck. Neither fact changes the verdict you are asked for.
Reading your score
Your raw total out of eighteen is mapped onto the familiar scale where 100 is the population average and fifteen points is one standard deviation. Because eighteen items is a short test, each answer moves the number several points, so read your result as the centre of a band about ten points wide rather than as an exact value.
| Correct | Approx. score | What it suggests |
|---|---|---|
| 17–18 | 130+ | You are checking form, not plausibility, almost every time |
| 15–16 | 118–128 | Strong; the misses are usually "only" or the conditionals |
| 12–14 | 105–117 | Above average; belief bias catches you on two or three items |
| 9–11 | 92–104 | Typical adult performance without logic training |
| 6–8 | 78–90 | Plausibility is driving your answers more than structure |
Three habits that raise a syllogism score
First, translate before you judge. "Only ticket holders were allowed in" does not mean every ticket holder got in; it means everyone who got in held a ticket. Rewriting the premise in the "all X are Y" shape before you look at the conclusion removes most of the difficulty from that family of items.
Second, look for a counterexample rather than a proof. An argument is invalid the moment you can imagine one situation in which both premises hold and the conclusion fails. Two premises that both begin with "some" almost never support anything, because the two groups they describe may have no members in common at all.
Third, cover the conclusion. Read the premises, decide for yourself what they force, and only then uncover the stated conclusion and compare. Doing it in that order is the most reliable defence against belief bias that anyone has found, and it costs you a few seconds per item.
How this differs from the other reasoning tests here
Deductive reasoning tests in general cover a wider range of formats, including seating arrangements, ordering puzzles and rule-application grids. Verbal reasoning tests mix logic with reading comprehension and check whether you can extract claims from a paragraph in the first place. This page is narrower and harsher than either: no reading load, no arithmetic, no spatial component, nothing but the relationship between two statements and a third. If you score well here and poorly on a broader battery, the bottleneck is comprehension or speed rather than logic. If the reverse happens, you are probably reasoning from what sounds right instead of from what was written down.
Frequently asked questions
What is a syllogism test?
A syllogism test gives you two premises and asks whether a stated conclusion follows from them. You are judging the structure of the argument, not whether the sentences are true in the real world, which is why the premises are often deliberately odd.
Do I have to treat the premises as true?
Yes. Every item asks you to accept both premises exactly as written, even when they contradict what you know. If a premise says every mammal in the enclosure lays eggs, then inside that item it does, and your job is only to work out what must follow.
What is belief bias?
Belief bias is the tendency to call an argument valid because its conclusion sounds sensible, and invalid because the conclusion sounds wrong. Several items here pair a broken argument with a believable conclusion, and a watertight argument with an odd one, specifically to detect that habit.
How long does the syllogisms test take?
There are 18 items and a 15 minute limit, which works out at about 50 seconds each. Most people finish with time to spare, and the clock scores the test for you if it runs out.
What is a good score on this test?
Getting 13 or 14 of the 18 items right is a solid result for an adult with no formal logic training. Scores of 16 and above usually mean you are checking each argument by its form rather than by how plausible it sounds.
Is this syllogisms test free?
Yes. It is free online, there is no account, no email address and no payment step at any point, and you can retake it as often as you like.