Untimed online IQ test · 40 problems · five families · four forms
NEREUS: the five-family fluid reasoning test
In Greek myth, Nereus is the truthful Old Man of the Sea and the father of the Nereids. His test asks for the truth hidden in structure.
Forty original problems in five families of reasoning: structural analogies, hidden transformations, constraint reconstruction, invariant discovery and counterfactual reasoning. Work at your own pace, in as many sittings as you need; when you submit, your score and certificate appear at once. Take it again later on a form you have never seen.
- Untimed
- Four forms
- Retakes on new problems
- Instant certificate
How it works
Register and pay
Enter your name as it should appear on your certificate, and pay the US$50 fee through PayPal (account or card). Your attempt is ready the moment the payment completes, on a form you have never seen.
Read each family's guide page
Each family opens with a guide page and a worked example. Read it first: it is in the test, one click away.
Solve at your own pace
Move freely between the 40 problems and change answers whenever you like. Each answer is saved on the server as you give it; your private link reopens the test on any device, for 90 days.
Submit and get your certificate
Your raw score, IQ on the NEREUS model scale with its interval, a profile by family and a PDF certificate anyone can verify, at once, with a copy by email.
What NEREUS measures
NEREUS asks you to find structure that no one states: the relation behind two pairs of letters, the hidden rearrangement and relabeling a machine performs, the one arrangement that satisfies every constraint, what a process can never change, and what would have happened under other conditions. Each family opens with a guide page and a worked example; the eight problems that follow grow harder.
- Family A. Structural analogies
- Family B. Hidden transformations
- Family C. Constraint reconstruction
- Family D. Invariant discovery
- Family E. Counterfactual reasoning
Retakes: up to four attempts per person, each on a form you have never seen, at least 90 days after the previous one, each with its own fee (US$50). Your best result counts for the societies.
Built to keep outside help out
- Keys on the server. The answer keys never reach your browser, and the result never shows which problems you solved.
- Four forms. Each form's pages are shown only to its own sessions, and every attempt is on a form you have never seen.
- Watermarked pages. Every page is drawn on the screen with a faint watermark of your name and certificate ID.
- Recorded. Leaving the test window, screenshot shortcuts (Print Screen, Windows+Shift+S, Command+Shift+3, 4 or 5), printing (Ctrl+P or Command+P), copy, right-click and drag attempts, paste attempts (pasting is switched off) and AI assistant add-ons in the page are recorded problem by problem, with the server's own times. Printing shows blank pages.
- Checked. The server notes right answers given moments after a long absence from the test, and many problems answered right in a few seconds.
- Sealed and reported. The record is sealed when you submit; its fingerprint is printed on your certificate, so it cannot be changed afterwards. The author's integrity report of your attempt lists all of it, problem by problem.
No untimed online test can rule out every form of help. These measures make it visible, and the author reviews every result before it counts for a society.
Your result
Scored with the provisional model norms M0.2 of NEREUS (model-based; no norming sample yet). Deviation IQ, mean 100, SD 15. No percentile is reported: no norming sample has been tested yet, so a score is a position on the test's own scale.
Societies. IQ 147 or higher meets the criterion of the Nereid Society, IQ 160 that of the Mesopelagic Society (with a one-time membership fee), and IQ 190, 205 and 220 those of the Aphotic, Hadal and Exocosm Societies. Just below the criteria, IQ 135 to 146 qualifies for associate membership of the Nereid Society and IQ 180 to 189 for subscription to the Aphotic Society, each with a one-time admission fee. Your best attempt counts.
Take NEREUS online
A computer or tablet is best: the problem pages are detailed, and a larger screen shows them whole. A phone works too (zoom in on the page). Keep scratch paper ready.
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Please check back soon, or take THETIS, the adaptive online test, today.
Your details
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Payment
- NEREUS: one untimed attempt, its scoring and certificateUS$50
- Name on certificate
PayPal processes the payment; you can pay with a PayPal account or a debit or credit card. Your test is ready the moment the payment completes, and you can begin at once or later.
Have a code?
Your test is ready,
- Untimed. Once you begin, your test stays open for 90 days. Work in as many sittings as you like; your private link reopens it on any device.
- Start with each family's guide page: it explains the notation. Then answer the 40 problems in any order, and change answers as often as you like before you submit.
- A problem scores one point only when every part of its answer is right. No marks are taken off for wrong answers, so answer every problem.
- Answers are saved on the server as you give them. Nothing tells you whether an answer is right, and the result never shows which problems you solved.
- Work alone, with scratch paper only. Leaving the test window, screenshot shortcuts, printing, and copy or paste attempts are recorded with your result for the author's review.
Camera check (required)
While a problem is on screen, this page watches your camera for a phone, another person or an empty seat. The check runs in your own browser: the video never leaves your device. When it sees one of these, it keeps a small still picture for the author's review, deleted after 90 days. It never changes your score, and your certificate's verification page shows that it covered your whole test.
- Sit facing the camera in good light, with your face in view.
- Keep your phone and other devices out of reach, and work alone.
- If the camera stops, the problem is covered until it is back. Breaks are fine: close the page or step away between problems.
Your answer
Submit your answers for scoring?
Your NEREUS result
- Raw score
- 90% interval
- Form
- By family
Your certificate
Certificate ID . Anyone can check it at .
Record fingerprint : the server sealed your answers and what this page recorded when you submitted. The same fingerprint is on your certificate, so the record can never be changed without the change showing.
Next: take THETIS (adaptive) or RUFIT (timed) for a second, independent measure, or read about the five societies.
NEREUS: questions
What is NEREUS?
An untimed online test of fluid reasoning: 40 constructed-response problems in five families of eight (structural analogies, hidden transformations, constraint reconstruction, invariant discovery and counterfactual reasoning), from the NEREUS research edition V0.2.0. Each family opens with a guide page and a worked example. Every problem has exactly one answer under its printed rules, proven by an independent computer check, and you answer in a panel built for it: letter pairs, frames of shapes, arrangements, tables and cells.
How long do I have, and can I take breaks?
NEREUS is untimed. From the moment you begin, your attempt stays open for 90 days: work in as many sittings as you like, on any device, with your private link. Every answer is saved on the server as you give it. When you are done, submit: your result and certificate appear at once. An attempt still open after 90 days is submitted with the answers saved by then.
Can I take it more than once?
Yes: up to four attempts, each on a form you have never seen. NEREUS has four forms built on the same blueprint with different problems, so what you learned on one form does not carry its answers to the next. A new attempt can begin 90 days after your previous one was submitted, and one attempt is open at a time. Every attempt has its own fee and its own certificate, and your best result counts for the societies. Register every attempt with the same email. Only first attempts go into the norms data.
What does the fee cover?
The US$50 fee, paid through PayPal before the attempt opens, covers one attempt: the online test on a new form, its scoring, your result with its PDF certificate, and the review of one society application. Each retake has its own fee. Admission as a full member of a society carries no further fee.
How precise is a NEREUS score?
NEREUS is a research edition. Its provisional model norms M0.2 place raw scores 1 to 39 between IQ 103 and 239 (SD 15), using a model whose item difficulties are assumed: no norming sample has been tested yet, so a score is a provisional position on the NEREUS scale, not a percentile of the population, and no percentile is reported. The model error is about 5.5 IQ points from about IQ 130 to 210, and a perfect score is shown at the nominal cap of IQ 250. The four forms are built alike, on the same blueprint, but are not yet equated. The norms will be replaced by empirical norms as results come in.
Does a NEREUS result count for the societies?
Yes. IQ 147 or higher meets the criterion of the Nereid Society, and the fee covers the review of your application. IQ 160 meets that of the Mesopelagic Society, whose membership carries a one-time fee, and IQ 190, 205 and 220 those of the Aphotic, Hadal and Exocosm Societies. Associate membership of the Nereid Society (IQ 135 to 146) and subscription to the Aphotic Society (IQ 180 to 189) carry a one-time admission fee. Your best attempt counts.
How does the online test keep AI and other help out?
The answer keys never leave the server, and your result never shows which problems you solved. Each form's pages are shown only to its own sessions, and a retake is always on a form you have never seen. Each page is drawn on the screen with a faint watermark of your name and certificate ID. While a problem is on screen, the test page records leaving the test window, screenshot shortcuts (Print Screen, Windows+Shift+S, Command+Shift+3, 4 or 5), printing (Ctrl+P or Command+P), copy, right-click and drag attempts, attempts to paste into the answer fields (pasting is switched off), and AI assistant add-ons that insert themselves into the page; the server keeps its own times and notes right answers given moments after a long absence. The record is sealed when you submit, and its fingerprint is printed on your certificate. None of this changes a score: the author reviews it before any society admission. The author's integrity report of each attempt lists all of it, problem by problem. An untimed test cannot rule out every form of help, which is why you declare that you will work alone, and why the author reviews every result before it counts for a society.
What if I lose my link or change devices?
Your private link (shown when your test is ready, and kept in this browser) reopens your test on any device. If you lose it, use “Recover my test” with the PayPal Transaction ID from your receipt and the email you registered with. Answers that are complete are saved on the server; a part you have only begun is kept in the browser you were using until you complete it.
Rules, fee and privacy
Test rules
Work on NEREUS alone, with scratch paper only: no person, AI system, search engine, calculator, program, published solution or other aid. Do not copy, photograph, record or share the problems or your answers. Each person may take NEREUS up to four times, always registered with the same email: each attempt is on a form the person has never seen, begins at least 90 days after the previous one was submitted, and has its own fee and certificate. One attempt is open at a time, and a test belongs to the person registered for it. You may take as many breaks as you like within the 90 days. Results that show signs of outside help may be withheld from society admission or withdrawn.
Fee and refunds
The fee is US$50 for each attempt, paid through PayPal (PayPal account or card) before the attempt opens. It covers the online administration of one attempt, scoring, your result and certificate, and the review of one society application. Because the problems are shown as soon as a test begins, a test that has begun cannot be refunded. If a payment went through but the test did not open, use “Recover my test”, or write to jresquites@mensaphilippines.org with your PayPal Transaction ID.
Privacy notice
Your name, email, year of birth, country and earlier scores are used to run your test, to issue and verify your certificate, to build the norms and, with your consent, in de-identified research summaries. Your answers, the times the server kept and the integrity record (departures from the test window, screenshot shortcuts, copy, paste or print attempts, and the names of AI assistant add-ons found in the page; other add-ons are never recorded) are kept with your result for scoring, norm updates and the review of society applications. The camera check, which every test requires, runs in your own browser: the video from your camera is analyzed on your device and is never sent or stored. When it sees a phone, another person or an empty seat while a problem is on screen, the page sends one small still picture (160 by 120 pixels) with its time, kept for the author's review and deleted 90 days after it was taken; its summary of each problem (how long it watched, and when it saw any of these) is kept with your integrity record. The detector's program and model load from public servers (jsDelivr and Google), which see your device's address as any website does. How you reached the site (the name of the site or app that linked to it, or the tag in the link you followed, which your browser keeps for 30 days) is recorded with your payment, without your name, to count which channels bring candidates. When your test ends, your result, the private link to it and the link to your certificate are emailed to you (through Resend, an email service). Your email is never shown publicly, and you can hide your name on the public verification page at any time. Data are stored by Netlify and Redis Cloud and are never sold.