THE ARTICLE · 8 MIN
Think Again is a book about changing your mind, by an organisational psychologist who teaches at Wharton. Here are its big ideas in our own words, what research says about the studies it leans on, and a few small practices drawn from the parts that hold up.
About the book
Think Again: The Power of Knowing What You Don’t Know is by Adam Grant. Viking published it in hardcover on 2 February 2021; Google Books lists it at 320 pages, and a paperback followed from Penguin Books on 26 December 2023. The publisher sums up its argument in one sentence: “We think too much like preachers defending our sacred beliefs, prosecutors proving the other side wrong, and politicians campaigning for approval—and too little like scientists searching for truth.”
It is a general-audience book that, in a cover blurb’s words, “weaves together research and storytelling”. The author’s own discussion guide groups its themes in three levels: individual rethinking, interpersonal rethinking (opening other people’s minds) and collective rethinking (schools, workplaces and communities).
The book is in copyright, so we did not read it in full. We read the publisher’s pages, the author’s website and discussion guide, a 2021 interview with him, and short passages of the 2021 Viking edition through the Google Books search-inside tool. Page numbers below are from that edition.
The big ideas
1. Drop your tools
The book opens with the Mann Gulch fire of 1949, in which a crew of smokejumpers was overtaken by a wildfire in Montana. The foreman, Wagner Dodge, survived by lighting an escape fire and sheltering in the burned-over patch. Grant uses the story as a metaphor: “You may not carry an ax or a shovel, but you do have some cognitive tools that you use regularly.” As we read it, the point is that the habits and beliefs we rely on can become a weight we fail to put down.
2. Preacher, prosecutor, politician, or scientist
Grant describes three modes we fall into. In preacher mode we defend beliefs we hold sacred; in prosecutor mode, in the book’s words, “we marshal arguments to prove them wrong”; in politician mode we campaign for an audience’s approval. He recommends a fourth, the scientist. In a 2021 interview he put it this way: “when I start to form an opinion, I should treat it as a hypothesis”.
3. Confidence and competence are not the same thing
A chapter on overconfidence draws on the Dunning-Kruger effect, which the book describes this way: “it’s when we lack competence that we’re most likely to be brimming with overconfidence.” Grant uses the label “Mount Stupid” for the point where a little knowledge makes us feel expert, and his discussion guide speaks of “confident humility”. The book also argues that feeling like an impostor can be useful: in its words, it “can make us better learners”.
4. Clever is not the same as open-minded
The publisher’s description puts it bluntly: “Intelligence is no cure, and it can even be a curse: being good at thinking can make us worse at rethinking.” It goes on: “The brighter we are, the blinder to our own limitations we can become.”
5. Think like a scientist, even in business
Grant describes an experiment with Italian startups, most of which “had yet to bring in any revenue”. Founders who were taught to treat their plans as hypotheses and test them did better than founders who received the same training without that method.
6. Change minds by listening, not lecturing
The book’s middle section is about rethinking with other people. Grant describes motivational interviewing, a counselling method built on open questions, affirming, reflective listening and summarising, and tells the story of someone the publisher calls a “vaccine whisperer” who used it with hesitant parents. One of his guiding principles, in the publisher’s words, is to “argue like he’s right but listen like he’s wrong.”
7. Build places where rethinking is normal
The book also covers habits and groups: building a “challenge network” of people who will tell you when you are wrong, encouraging disagreement about tasks without letting it become personal, and, in its last part, schools and workplaces that build “a learning culture”, along with regular “career checkups” that ask whether a plan still fits.
What holds up
The book’s core framework is sourced and its opening story is accurate. Several of the studies it leans on, though, are disputed or depend on small samples, and two of its practical claims hold up only with limits. The rows above give each claim, our verdict and the source.
A note on the Italian startup numbers
This is one of the book’s most concrete examples, so it is worth looking at closely. The book reports that the scientific-thinking group “averaged over $12,000 in revenue”. In the published paper, revenue is counted in euros, and only 17 of the 116 startups earned any revenue during the study: 9 in the trained group and 8 in the comparison group. An average across so few earning firms can move a lot with one or two of them. The later, larger study by the same team, which pooled the original trial with three new ones, supports the decision-making part of the finding: trained founders were more willing to drop ideas. It also found that they earned more on average, by about 7,000 euros, though the difference was statistically clear in only one of the three new trials, and the authors note that many firms earned nothing at all.
How to use it
These practices come only from the parts that hold up. They describe what people do; what fits your situation is your call.
- Naming the mode. Noticing, in the middle of an argument, whether you are defending, prosecuting or campaigning is a quick check drawn from Tetlock’s framework. It is a way of looking rather than a tested technique, but it costs nothing to try.
- Revisiting test answers you feel unsure about. The research on answer-changing suggests that a second look, guided by how confident you feel about each answer, more often helps than hurts.
- Asking before telling. Motivational interviewing’s core moves, open questions and reflecting back what you hear, have some evidence behind them, mostly for short-term change, and they are easy to try in an ordinary conversation.
- Treating a plan as a hypothesis. The startup studies suggest that one clear benefit of testing a plan is being readier to drop a weak one early, an idea that carries over to many projects beyond business.
Who it’s for, and who can skip it
It suits readers who like ideas carried by stories, and anyone who wants to get better at disagreeing or at changing their own mind. Readers who want to judge the evidence for each claim will find the stories more vivid than the studies are strong; the research above is the place to look for that. Readers who already know Tetlock’s work on forecasting, or the cognitive-bias literature, will recognise much of the first part.
If you liked this
- Cognitive biases, checked: the Dunning-Kruger effect and other famous findings, and whether they held up when studies were run again.
- How to check something online before you share it: a short method for testing a claim, which puts the book’s scientist mode into practice.
- Older Than You Think, Part 2: where the “Mount Stupid” chart comes from, and why it is not in the original study.
Sources
- A. Grant, Think Again: The Power of Knowing What You Don’t Know (Viking, 2021): publisher’s page, short passages via Google Books and the publisher’s sample of the prologue and chapter 1 (UK edition), the author’s book page and discussion guide.
- V. Shah, “Adam Grant on Think Again: embracing being wrong”, Thought Economics (9 February 2021).
- P. E. Tetlock, “Social functionalist frameworks for judgment and choice: intuitive politicians, theologians, and prosecutors”, Psychological Review 109 (2002).
- J. Kruger and D. Dunning, “Unskilled and unaware of it”, Journal of Personality and Social Psychology 77 (1999); G. E. Gignac and M. Zajenkowski, “The Dunning-Kruger effect is (mostly) a statistical artefact”, Intelligence 80 (2020); R. A. Jansen, A. N. Rafferty and T. L. Griffiths, “A rational model of the Dunning-Kruger effect supports insensitivity to evidence in low performers”, Nature Human Behaviour (2021); C. Sanchez and D. Dunning, “Overconfidence among beginners: is a little learning a dangerous thing?”, Journal of Personality and Social Psychology 114 (2018).
- D. M. Kahan, E. Peters, E. C. Dawson and P. Slovic, “Motivated numeracy and enlightened self-government”, Behavioural Public Policy 1 (2017); E. Persson et al., “A preregistered replication of motivated numeracy”, Cognition (2021); M. N. Stagnaro, B. M. Tappin and D. G. Rand, “No association between numerical ability and politically motivated reasoning in a large US probability sample”, PNAS 120 (2023).
- A. Camuffo, A. Cordova, A. Gambardella and C. Spina, “A scientific approach to entrepreneurial decision making: evidence from a randomized control trial”, Management Science 66 (2020); A. Camuffo et al., “A scientific approach to entrepreneurial decision-making: large-scale replication and extension”, Strategic Management Journal (2024, open access); E. Novelli and C. Spina, “Making business model decisions like scientists”, Strategic Management Journal (2024).
- A. Gagneur et al., “A postpartum vaccination promotion intervention using motivational interviewing techniques improves short-term vaccine coverage: PromoVac study”, BMC Public Health 18 (2018); L. Ramalli et al., “Sustained impact of motivational interviewing on reducing vaccine hesitancy among postpartum mothers”, Human Vaccines & Immunotherapeutics (2026); H. Frost et al., “Effectiveness of motivational interviewing on adult behaviour change in health and social care settings: a systematic review of reviews”, PLoS ONE 13 (2018); S. Labbé et al., “Addressing vaccine hesitancy: a systematic review comparing the efficacy of motivational versus educational interventions on vaccination uptake”, Translational Behavioral Medicine 15 (2025).
- J. Kruger, D. Wirtz and D. T. Miller, “Counterfactual thinking and the first instinct fallacy”, Journal of Personality and Social Psychology 88 (2005); J. J. Couchman et al., “The instinct fallacy: the metacognition of answering and revising during college exams”, Metacognition and Learning 11 (published online 2015).
- US Forest Service, Missoula Fire Sciences Laboratory, “Mann Gulch History”; Forest History Society, “Mann Gulch Fire, 1949”.
Checked October 2026. What we read: the publisher’s page, the author’s book page and discussion guide, the 2021 interview, and short search-inside passages of the 2021 Viking edition, the publisher’s sample of the prologue and chapter 1 (not the whole book); the two Mann Gulch history pages in full; the 2018 Quebec study and the 2018 review in full; the 2020 startup paper and its 2024 follow-up in full; and the other studies above (abstracts).
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