The State of Thinking 2026
The most-referenced mental models and biases, measured — not voted
The most-referenced mental model of 2026 is Second-order thinking — cross-referenced 57 times across ReadGlobe’s 148 ideas, 46 comparisons, 22 working-life hubs and 50 books. Among biases, Confirmation bias leads with 40 references.
Most “top mental models” lists are votes or vibes. This one is a measurement: every ranking below is the count of real cross-references inside one editorially-curated corpus — which ideas other ideas point to, which ones the comparisons argue about, which ones practitioners’ toolkits and guided reading rooms keep reaching for, and which ones the canonical books teach. The counts are reproducible from the open dataset.
The 10 most-referenced mental models
| # | Idea | Refs | Where it’s referenced |
|---|---|---|---|
| 1 | Second-order thinking | 57 | 40 related ideas · 6 comparisons · 6 hubs · 1 rooms · 4 books |
| 2 | First-principles thinking | 41 | 26 related ideas · 7 comparisons · 5 hubs · 1 rooms · 2 books |
| 3 | Inversion | 37 | 27 related ideas · 3 comparisons · 3 hubs · 1 rooms · 3 books |
| 4 | Margin of safety | 37 | 28 related ideas · 3 comparisons · 3 hubs · 1 rooms · 2 books |
| 5 | The map is not the territory | 35 | 27 related ideas · 2 comparisons · 4 hubs · 1 rooms · 1 books |
| 6 | Opportunity cost | 30 | 20 related ideas · 1 comparisons · 7 hubs · 2 books |
| 7 | Incentives | 29 | 17 related ideas · 5 hubs · 7 books |
| 8 | Circle of competence | 28 | 13 related ideas · 4 comparisons · 4 hubs · 1 rooms · 6 books |
| 9 | Bayesian thinking | 24 | 17 related ideas · 3 comparisons · 1 rooms · 3 books |
| 10 | Compounding | 22 | 14 related ideas · 2 comparisons · 4 hubs · 2 books |
The pattern is striking: the winners are not techniques but lenses — second-order thinking, first-principles thinking, margin of safety. The ideas everything else leans on.
The 10 most-referenced cognitive biases
| # | Idea | Refs | Where it’s referenced |
|---|---|---|---|
| 1 | Confirmation bias | 40 | 20 related ideas · 3 comparisons · 12 hubs · 1 rooms · 4 books |
| 2 | Availability heuristic | 31 | 19 related ideas · 4 comparisons · 6 hubs · 2 books |
| 3 | Loss aversion | 31 | 14 related ideas · 5 comparisons · 5 hubs · 1 rooms · 6 books |
| 4 | Anchoring bias | 25 | 10 related ideas · 3 comparisons · 11 hubs · 1 books |
| 5 | Sunk-cost fallacy | 24 | 7 related ideas · 3 comparisons · 11 hubs · 1 rooms · 2 books |
| 6 | Self-serving bias | 20 | 12 related ideas · 3 comparisons · 4 hubs · 1 books |
| 7 | Optimism bias | 19 | 12 related ideas · 2 comparisons · 4 hubs · 1 books |
| 8 | Halo effect | 18 | 8 related ideas · 3 comparisons · 5 hubs · 1 rooms · 1 books |
| 9 | Fundamental attribution error | 18 | 7 related ideas · 3 comparisons · 7 hubs · 1 rooms |
| 10 | Survivorship bias | 17 | 7 related ideas · 1 comparisons · 5 hubs · 4 books |
Confirmation bias tops the list for a reason: it shows up in more working situations — hiring, investing, meetings, product decisions — than any other distortion of judgment.
The books that teach the most of these ideas
- Thinking in Systems by Donella Meadows — teaches 8 of the ideas in this reference
- Thinking, Fast and Slow by Daniel Kahneman — teaches 7 of the ideas in this reference
- The Great Mental Models, Volume 1 by Shane Parrish — teaches 7 of the ideas in this reference
- Predictably Irrational by Dan Ariely — teaches 6 of the ideas in this reference
- Mistakes Were Made (But Not by Me) by Carol Tavris & Elliot Aronson — teaches 6 of the ideas in this reference
Questions people ask
- What is the most-referenced mental model?
- Second-order thinking — cross-referenced 57 times across ReadGlobe’s corpus (related ideas, comparisons, working-life hubs, reading rooms and books), ahead of First-principles thinking (41) and Inversion (37).
- What is the most-referenced cognitive bias?
- Confirmation bias — cross-referenced 40 times, ahead of Availability heuristic (31) and Loss aversion (31).
- Which book teaches the most mental models and biases?
- Thinking in Systems by Donella Meadows, which teaches 8 of the ideas in this reference — more than any other book in the library.
- Can I cite or republish these findings?
- Yes — the report and its dataset are CC BY 4.0: free to cite, quote or republish with attribution to “ReadGlobe (readglobe.com)”. A machine-readable version is at /api/state-of-thinking-2026.json.
Methodology — how the counts are made
Each idea’s score is the number of inbound references across five real edge types in the ReadGlobe corpus (88 models · 60 biases · 46 comparisons · 22 hubs · 6 reading rooms · 50 books): related-idea links from other entries, comparison pages that argue it head-to-head, working-life hubs that curate it, guided reading rooms that stop at it, and books in the library that teach it. Counts measure this corpus, not the whole world — but the corpus is editorially curated from the canonical literature, which is what makes the signal meaningful. No votes, no view-counts, nothing self-reported.
License: CC BY 4.0 — free to cite, quote or republish with attribution to “ReadGlobe (readglobe.com)”. Machine-readable: /api/state-of-thinking-2026.json.
Go deeper: the models by what you do · the biases by situation · more Originals