From overcoming climate change and COVID-19 to sludge and pension plan design,
The final edition of the global bestseller "Nudge," which completely changed the 21st century.

The global bestseller "Nudge," which sparked a worldwide craze for "nudge," has been reborn as an even more powerful final edition, "Nudge: The Final Edition," 13 years after its publication.
First published in the United States in 2008, Nudge, the century's greatest economics classic that completely overturned perspectives on human behavior and choice, has been recognized by 2 million readers and won the Nobel Prize in Economics. Now, armed with even more powerful choice design ideas and up-to-date examples, it's back.
As the preface states, “We threw out the old and filled in the new,” authors Richard Thaler and Cass Sunstein have completely rewritten about half of the content to reflect the world that has changed significantly over the past 13 years.


This final edition guides readers into a more expansive world of nudge, exploring cutting-edge cases that reflect our times, including the COVID-19 pandemic, which vividly demonstrated social nudges, and climate change, which has become an urgent global issue.
It also introduces emerging choice design ideas such as sludge, curation, smart disclosure, and personalized default settings, and delves deeper into topics closely related to individual decision-making in real life, such as savings, insurance, and loans.
In addition, we look back at the nudges applied and their effects in designing public policies such as retirement pensions, health insurance, and organ donation, and consider future nudges.

Daniel Kahneman, a Nobel Prize winner in economics, praised this final edition, which has been out for 13 years, saying, “If ‘Nudge’ changed the world, ‘Nudge: The Final Edition’ is truly amazing!”
Evolving into a fresh and modern version to keep pace with the changing times, "Nudge: The Final Edition" will once again completely change our perspective on humanity and the world.

But we were already looking through old manuscripts, and the COVID-19 pandemic was just around the corner.
Chapter 1 of "Nudge" deals with the iPod, which was incredibly sophisticated at the time but is now completely outdated... Oh my, looking back at that manuscript, it seems like such a long time ago.
But the overall content finds a solution that is still excellent even today, making marriage possible for same-sex couples.
Since then, many countries have solved that very problem in ways we never imagined were politically possible.
The problem was solved by enacting a law legalizing same-sex marriage.
Looking at these various points, we thought that there might be a need to organize some parts of Nudge.
…in military terms, this is called ‘mission creep.’
Eventually we decided to publish a revised edition.
And I planned to finish the revised manuscript in one summer.
But, strangely enough, the completed manuscript was not delivered to the publisher until the end of November of the same year.
---From "'Preface to the Final Edition of Nudge: The Final Edition'"

A famous passage from Mark Twain's novel The Adventures of Tom Sawyer illustrates this point well.
Tom, a mischievous boy, is punished by his Aunt Polly for his bad behavior.
The punishment is to paint the board fence that runs along the sidewalk in front of the house white.
Tom wants to play with his friends, but he can't and hates doing that boring work.
Besides, I'm sure my friends will pass by and tease me if they see me getting punished, and I don't want to be teased like that.
As Tom is painting, worrying about this, his friend Ben Rogers walks in.
Ben is holding a delicious apple in his hand.
Tom, seeing this, comes up with a plan to trick Ben.
Tom put all his heart into painting, as if he was having a lot of fun, and Ben, seeing this, thought that it must be very exciting and enjoyable.
Ben suggests that he try it too, but Tom refuses.
I can't give up something fun.
Eventually, Ben apologizes to Tom and begs him to give him the paintbrush and begin painting.
So by evening Aunt Polly's fence had been painted three times.
---「Chapter 6.
From "Wait, there's more"

Our two authors have friends in the Behavioral Insights team in London who tell us that PayPal's terms and conditions contain a whopping 36,275 words.
This is a little over a third of the book's length.
For that reason, we believe that no one, including PayPal employees, has read these terms from beginning to end.
The question is whether this can be called 'disclosure' in the sense that it allows consumers to read and know the necessary information in advance.
It can only be seen as an intentional obfuscation to prevent people from understanding the content.
To be clear, our authors did not intentionally use PayPal as an example.
I just gave an example from my friends on the Behavioral Insights team.
What's interesting about this disclosure is that while it's accessible online, it's ultimately just a massive pile of information.
It is difficult to read this content easily on a computer.
The goal of smart disclosure is to solve precisely this problem.
Taking travel products as an example, we can see how this problem can be improved.
---「Chapter 7.
From "Smart Public"

We use sludge to mean 'any aspect of a choice architecture that makes it difficult for people to achieve the desired outcome they want.'
If you can't get financial aid without filling out a 20-page form, you're in for a rude awakening.
If you can't get a student visa without going through four interviews, you're in for a real treat.
If you're having to navigate a complex website, fill out countless online forms and documents, and drive to a remote clinic for two hours to get tested for COVID-19 or get a vaccine, you're definitely being slogged through.
---「Chapter 8.
#Sludge"

These results demonstrate the power of choice architecture.
Let's compare the behavior of this company's employees, divided into three groups.
The first group is those who did not receive counseling.
This group was saving about 6 percent of their income when the "Save More for the Future" pension began, and their contribution rate remained the same for the next three years.
The second group is those who accepted the recommendation to raise the contribution rate by 5 percentage points.
Their contribution rate, which was 4 percent immediately after the first wage increase, jumped to 9 percent.
However, this contribution rate remained roughly the same for a long time thereafter.
The third group is those who have signed up for a 'saving more for the future' pension.
This group's original contribution rate was the lowest of the three groups, at 3 to 5 percent, but it steadily increased after joining the program, and after three years and six months, when their wages had increased four times, it had nearly quadrupled to 13.6 percent.
This figure is significantly higher than the 9 percent increase in contributions made by those who followed the recommendation to raise their contribution rates by 5 percentage points.
---「Chapter 9.
From "Nudges to Increase Savings"

A question we haven't yet explored is how long the effects of nudges last.
One possibility is that people initially exhibit default behaviors due to reasons such as status quo bias, laziness, or procrastination, but over time they refine their behavior and try to shift their initial choices toward more rational ones.
In such situations, the specific design provided by the choice architect ends up having only a temporary effect.
But if the nudge effect is to persist, choice architecture may play a crucial role, and the effect could last for decades.
The Swedish experience with the pension system can shed some light on the sustainability of nudge effects, as it provides data that can track what happened from its inception through the end of 2016.
---「Chapter 10.
From "Will Nudge Last Forever?"

A group of economists studied card users' answers to this question using British data, and later replicated the results using American data.
Before we actually hear what people did, let's ask Dan what he should do.
Anyway, Dan has to pay the minimum payment amount.
If you don't do that, you'll have to pay a lot of late fees.
After paying the minimum payments of $40 and $20, Dan's best strategy is to use the remaining money to pay off his high-interest credit card debt.
This is a simple and quite understandable rule.
Pay the minimum balance required by each credit card, and use the remaining money to pay off any debt on high-interest cards.
However, researchers found that only about 10 percent of the total sample followed this rule.
---「Chapter 11.
Borrow More Money Today: Secured Loans and Credit Cards

Bad choices have something in common.
This means choosing the one with the lower deductible.
In many cases, plans with higher deductibles are superior to plans with lower deductibles.
For example, one insurance plan had an annual deductible of $1,000 and an annual premium of $930.
This insurance plan is superior to a plan with a $500 deductible and a $1,568 premium, all other conditions being the same.
This is a problem that can be solved with simple math.
On the other hand, if you choose the latter insurance plan, you will have to pay $638 per year to reduce your deductible by $500.
This would cost you at least $138 more, and would also wipe out the $638 you could have saved if you never had to file a claim.
Employees who followed our easy rule of thumb to choose the one with the highest deduction would have avoided this trap.
---「Chapter 12.
Don't risk your life on trivial matters: Insurance"

Belgium, and particularly Flanders, has been a pioneer in this type of organ donor recruitment.
The 2018 television program Make Belgium Great Again dedicated an episode to the importance of organ donation, combining an emotional appeal with a call to action for viewers.
The program also worked in collaboration with 240 municipalities across Flanders, which opened their offices the following Sunday to accept applications for organ donation.
As a result, more than 26,000 people registered as organ donors, a remarkable achievement considering that the region had previously registered between 7,000 and 8,000 organ donors annually.
…Belgium also allowed citizens to register as organ donors during local elections.
The Belgian government introduced a program called the "Federal Truck," which, from 2015 to 2019, involved touring the country with trucks to educate students about organ transplants and encourage families to talk about organ donation at home.
As a result of these efforts, the number of people registered as organ donors in Belgium has more than tripled since 2009, while the number of people opting out has remained stagnant.

---「Chapter 13.
From "Organ Donation: The Illusion of a Default Solution"