Lateral Thinking: Edward de Bono's Techniques Explained

A money lender agrees to cancel a merchant’s debt on one condition: the merchant’s daughter picks a stone from one of two bags, and a black stone means she must marry him. She sees him put a black stone in both bags. In the solution Edward de Bono gave when he introduced lateral thinking in his 1967 book The Use of Lateral Thinking, she picks a bag, fumbles her stone onto the pebbled path, and lets everyone assume it was white, since the stone left behind is black.¹

That story is the idea in miniature. Lateral thinking means solving a problem by changing how you see it rather than pushing harder along the obvious line of reasoning. De Bono turned it into deliberate techniques: random entry, provocation, challenge and the concept fan, each worked through below on one ordinary problem. The evidence is thin. One of the few published evaluations of de Bono’s school course, a 1996 Australian study of Aboriginal children, found gains in creative thinking but none in school achievement.² For a wider menu of methods ranked by evidence, see these idea-generation techniques and how well each is tested.

Prefer to watch? The video covers the same ground as this article.

VideoLateral Thinking: Four Techniques to Get UnstuckWiserHours

What is lateral thinking?

Lateral thinking is a way of solving problems indirectly, by reasoning that is not immediately obvious, as Wikipedia’s entry on the term puts it. Edward de Bono coined it in 1967, and the entry treats it as close to “thinking outside the box”.³ What sets it apart is that de Bono described it as a skill with named tools.

De Bono was a Maltese doctor, born in 1933, who studied psychology and physiology at Oxford as a Rhodes scholar and wrote more than 60 books before his death in 2021.¹ His core claim was that lateral thinking involves a switch from a familiar pattern to a new, unexpected one, and that the switch can be cultivated on purpose.³ He valued humor for the same reason: a joke works by shifting how you see something.¹

The pebble story shows the switch. Everyone in it is thinking about which stone the daughter will draw. Her answer moves attention to the stone left in the bag, where the money lender’s trick works against him. Nothing in the setup changed; only the part of the problem she looked at.

When you are stuck, the problem is often a single way of framing it. Changing the frame is a separate step from working harder inside it.

Lateral versus vertical thinking: the difference

Vertical thinking, also de Bono’s term, moves step by step toward one answer and discards what seems irrelevant; lateral thinking looks for a different direction altogether. Wikipedia’s article on vertical thinking quotes his short definition of it.⁴

Vertical thinking is selection by exclusion.

A 2008 article for physician leaders by James Hernandez and Prathibha Varkey, two US doctors at the Mayo Clinic, set out the contrast as a table. It is their summary of de Bono’s ideas, an expert opinion rather than research, but it captures the difference well.

Neither column is the better one. Hernandez and Varkey argue that leaders need both kinds.⁵ Wikipedia’s summary of de Bono’s 1970 book makes the same point: nobody has to stick to one method, and a balance of the two usually works best.⁴ Think of a delayed commute. Vertical thinking finds the fastest alternative route. Lateral thinking asks whether the first hour of work needs to happen at the office at all. The first answer is reliable; the second might change the problem.

Lateral thinking examples: four of de Bono’s techniques on one problem

De Bono sorted his tools into four groups: tools that generate ideas, tools that focus the search, tools that harvest value from the output and tools that shape ideas to real constraints.³ The four below are the best-known generating tools. To show how each one works, they are applied to one illustrative problem: a team’s weekly status meeting that always overruns and leaves most people bored.

Random entry: connect a random word to the problem

Random entry means taking a word you did not choose and forcing links between it and your problem. De Bono’s own example applied the word “nose” to an office photocopier and arrived at a copier that gives off a lavender smell when it runs low on paper.³ The word must be genuinely random: if you pick it, your existing thinking picks it for you. The University of Udine’s techniques handbook suggests keeping your own list of 60 words (fire, desk, shoes and so on) and using the seconds on a watch to choose one.⁶

Applied to the meeting, the word “postcard” suggests several links. A postcard holds only a few lines, so every update could be limited to what fits on one. Postcards arrive before the visit, so updates could be written and read before the meeting. Neither idea came from thinking harder about meetings. Force at least three links before you judge any.

Provocation and movement: say “po”, then move

A provocation is a statement you know is wrong or impossible, used to jolt thinking somewhere new.³ De Bono created the word “po” to signal one: an idea meant to move thinking forward to a new place.⁷ One of his examples tackled river pollution with “po: the factory is downstream of itself”, leading to a rule that a factory must take in water downstream of its own outflow. He wrote that the idea later became law in some countries.³

The provocation is only half the technique. The other half is movement: getting from the impossible statement to a usable idea by extracting a principle, focusing on what is different, imagining it step by step, or looking for positive aspects or special circumstances where it would work.³ For the meeting, try “po: the meeting has no talking”. Extracting a principle gives you this: updates do not need voices. That moves toward written updates beforehand and a short spoken meeting about blockers only.

Challenge: ask why it is done this way

A challenge asks, without attacking, why something exists or is done the way it is, even when nothing seems wrong. Wikipedia’s example is the handle on a coffee cup: it exists because the cup is too hot to hold, which suggests insulated grips, a separate holder, or coffee that is served less hot.³ The aim is to stop treating the current way as the only one; the Udine handbook describes blocking the usual route, escaping its assumptions or dropping the step altogether.⁸

For the meeting, ask: why weekly, why everyone, why spoken, why an hour? Each answer may be perfectly good, but asking turns a fixed arrangement into a choice.

Concept fan: step back to the purpose, then fan out

The concept fan steps back from a problem to its purpose and then fans outward again in three levels: broad directions, concepts that serve each direction, and concrete ideas that put each concept into practice.⁹ The Udine handbook’s example starts with cleaning a local beach. If the first ideas fall short, it widens the problem to controlling pollution that enters the sea, which opens new options.⁹

1. Purpose: keep the team coordinated
2. Directions: share progress; remove blockers
3. Concepts: written updates or a dashboard; a short huddle only when someone is stuck
4. Ideas: the concrete versions you would try, such as updates written before the meeting

For the meeting, the purpose might be keeping the team coordinated. Two directions follow: share progress, and remove blockers. Sharing progress could use written updates or a dashboard; removing blockers could use a short huddle called only when someone is stuck. The fan shows that the weekly meeting was one idea among several serving the same purpose. De Bono’s Six Thinking Hats, in which meeting attendees wear imaginary color-coded hats for different kinds of thinking, is a separate tool.¹

Does lateral thinking training work?

Whether lateral thinking training works is still poorly known, because de Bono’s methods have rarely been put through controlled studies. His school course, the CoRT thinking program (named after his Cognitive Research Trust), has a handful of published evaluations, and their results do not agree.¹⁰

The study

Limited evidence

CoRT lessons with Aboriginal children in Australia (1996)

S. M. Ritchie and J. Edwards tested de Bono’s CoRT course with Aboriginal children in mainstream Australian classrooms. The course was linked to better creative thinking, but the authors found no gains in scholastic aptitude, school achievement, thinking approaches, self-concept as a thinker or sense of control.²

The result is useful because it separates two claims. The narrow one, that practicing the techniques makes people better at generating ideas, gets some support. The broad one, that it makes people better thinkers in general, does not. A workshop that leaves a team producing more options for a product name has done its job, even if nobody gets better at budgeting or writing reports afterwards. Just the abstract of the study was readable for this guide, so how large the gain was and how the study was designed remain unknown.

Reviewers outside de Bono’s circle reach similar verdicts. David Moseley and colleagues, evaluating thinking frameworks for a Cambridge University Press handbook, found sparse evidence that CoRT or Six Thinking Hats training produces general improvements in thinking. They noted an early evaluation reporting benefits for pupils with special educational needs.¹⁰ Robert Sternberg and Todd Lubart, in Cambridge’s Handbook of Creativity, called de Bono perhaps the foremost proponent of a “pragmatic approach” to creativity that cares about developing it but almost not at all about testing whether its ideas are valid, and noted his work’s apparent commercial success.¹⁰ A 2020 essay in Aeon by the writer Antonio Melechi went further, calling lateral thinking pseudoscience, derivative and untested.¹¹

Myth

Lateral thinking is a scientifically proven method.

Fact

Its techniques are widely taught, but controlled tests are few, and one school evaluation found creative-thinking gains that did not carry over to schoolwork.

Creativity training in general has better evidence. A 2004 meta-analysis of 70 training studies by Ginamarie Scott, Lyle Leritz and Michael Mumford found that well-designed programs were typically followed by gains in performance, and that the most successful taught thinking skills and rules of thumb with realistic exercises.¹² De Bono’s tools fit that description, which makes them plausible, though not proven. A 2024 review of 169 studies by Ut Na Sio and Hugues Lortie-Forgues found strong signs of publication biaspublication bias: The tendency for studies with striking or statistically significant results to be published, while quieter ones stay in the drawer. Since the missing studies are mostly the unimpressive ones, a pooled result tends to overstate the effect until it is corrected.Full entry in the glossary: once the authors adjusted for it, the average training effect shrank by about 40 to 45 percent.¹³ Expect a modest gain from practice.

How to use lateral thinking at work without overselling it

The techniques work best as a structured way to get unstuck, used in a time-boxed session and followed by ordinary judgment. The evidence above suggests practicing them on real problems and checking the results,.

Use them when a problem is open-ended and the obvious answers have run out: a process nobody has questioned in years, a product that looks dated, a meeting that wastes time. Wikipedia’s article on po works through a product seen as old-fashioned, with provocations such as “po: sell it to young people as a gift for old people”, some silly, some worth developing.⁷ Skip them when a task has one correct answer that careful logic will find.

Keep generating and judging apart, as de Bono’s split between generating tools and harvest tools implies.³ In a group, the research on why spoken brainstorming sessions underperform suggests having people write their links and provocations alone before anyone discusses them. Then switch modes: take the few ideas that survived and check them with the vertical questions about cost, risk and fit.

A 30-minute lateral thinking session

• Write the problem as one sentence
• Use a random word and force three links
• Write two po statements and move each to a principle
• Challenge three things that are done out of habit
• Fan out from the purpose to directions and concepts
• Only then judge the ideas for cost, risk and fit

The bottom line

The tools of lateral thinking are cheap to try, but the evidence that they make anyone a better thinker in general is thin. When you are stuck, run a 30-minute session to widen your options, then judge the ideas with ordinary, careful logic for cost, risk and fit.