Argue a real-life scenario, then catch the liar and the player quietly acting out a bias. 198 thinking traps, learnt by playing rather than studying.
Everyone gets a secret card: Homo Rationalis, a bias, maybe the liar or the moderator.
Draw a scenario, then draw For or Against and argue it, even if you'd normally disagree.
Stop the game to name the liar and what they lied about, or the biased player and their bias. Get it wrong and you sit out the round.
Catching the liar scores 3 points, a bias 1. First to 8 points wins, or with moderators, most points once everyone has moderated.
Every bias card names the trap, explains it in plain English and gives an everyday example, illustrated so it sticks.
A party game with real debates. Nobody notices they're learning psychology.
A 20-minute warm-up that gets a team naming its blind spots before a big decision.
A ready-made lesson on critical thinking, cognitive bias and reasoning errors.
Homo Rationalis is a card game about the ordinary, everyday ways we get decisions wrong, and how to get them a bit less wrong. 252 cards and an 8-page rules guide on 66 A4 pages, ready to print, cut and argue over.
For one teacher. Print as many copies as you need for your own students and classes.
Buy TeacherFor one organisation. Print and use it in your own internal workshops, for your own people.
Buy OrganisationIf you want to use it commercially, for example to run paid training, contact us and we'll talk about a workshop.
Read the full licence and refund terms
All prices include GST. After purchase you'll get a download page with print tips.
You can print and play Homo Rationalis at home with family and friends, as often as you like. Please keep the PDF to yourself, which means no uploading, forwarding or sharing it. Don't sell printed copies, and don't use the game in a classroom, a workplace or anything you charge for. Those uses have their own licences.
This licence is for one teacher, and it moves with you if you change schools. You can print as many copies as you need for your own students and classes, for as long as you teach. It doesn't stretch to colleagues, so each teacher who wants to use it needs their own licence. Please don't share the PDF, sell printed copies or use the game in paid tutoring or training.
This licence is for one organisation, across all its sites and teams. Anyone in it can print and use the game in internal workshops, team sessions and training for its own staff. Keep the PDF inside the organisation. You can't resell the game or printed copies, and you can't run it as paid training for clients or the public. If that's what you have in mind, contact us about a workshop.
Your licence doesn't expire. If we fix or correct this edition, we'll send you the updated file free; new editions aren't included. You can translate or adapt the cards for your own licensed use, but you can't share, publish or sell your version. The game and its contents stay the property of Decision Intelligence.
If the file is faulty, won't open or isn't as described, we'll fix it or refund you, as Australian Consumer Law requires. We don't refund a change of mind, but if you bought the wrong licence, tell us within 14 days and we'll switch it, charging or refunding the difference.
A$79.90 incl. GST and shipping (within Australia)Sold out
The printed deck has sold out. The digital edition is available now, or if you'd like a printed deck, email hello@decisionintel.co.
No. Every bias card explains itself in one sentence, with an everyday example.
Both. It plays like a party game; the learning happens in the arguments.
If the file is faulty, won't open or isn't as described, we'll fix it or refund you, as Australian Consumer Law requires. We don't refund a change of mind, but if you bought the wrong licence, tell us within 14 days and we'll switch it, charging or refunding the difference.