Introduction
The book starts with 13 simple questions about the state of the world. There is no trick about those questions, they are general and fact based. But when the author submit those questions to its audiance (students or other panels all over the world), he can see that almost everybody is wrong. It's not about not knowing the facts and guessing randomly, it's about being really wrong. Some chimps answering randomly the questions would get an average of 33% score. But what the author sees is that the score is on average lower than 33%. It means that people have huge misconceptions about the state of the world they live in.
This book is his final attempt to fix this misconception.
The gap instinct
It's very to imagine gaps between populations. We often refer to us as the rich and other as the poors, cutting the population in two different and distinct sets separated by a gap. This is a powerfull and frequent mental bias.
We have for example this image of poor people making a lot of babies who will mostly die, whereas rich people do fewer babies that are healthier. Taking graphs from the 1960, this would be true, but now, almost every country (but a few exceptions) are at the same levels as richers countries: infantile death has decreased a lot all over the world and the birth rate is lower.
The facts show that the opposite is generally true. We see overlaps between populations and the majority of people are in the middle. A better visualisation would be to split the population in four levels. We can then see that 5/7 of the population is in the levels 2 and 3.
The negativity instinct
Overall, there is a feeling of things being worst than before. The problem here is mixing the state of the things (or of some things) with the evolution of those. One cannot disagree with the fact that there are some really bad stuff happening (climate issues, people still leaving in Level 1, not null murder rate, etc). But looking at the numbers related to a lot of human aspects, the last hundred years have seen a lot of positive evolutions.
One tool to prevent this bias is to split the perception in the state and its evolution and admit the idea that things can be bad, but still improving at the same time.
Even though I adhere with the idea of the perception we have of things, saying that things are improving is relative to the subject and period we look at. This chapter is very much focused on humans on the last one or two centuries max. Can we really say that from the hunter/gatherer period to know things have improved for human condition? Can we say that animal condition is improving, that environement is getting better? I doubt it (even thought I don't have numbers or graphs right now for it).
The straight line instinct
We extrapole easily tendances to straight lines. Seeing the world population growing, make us think that it will continue growing a lot, which is not the prediction of the UN.
Every evolution does not follow a straight line.
The fear instinct
Evolution made us react on fear. For somebody on level 1, fearing snake is a good mechanism to stay alive. It means we are now left with a strong reaction to topics or subjects that are now very unrelated to level 4 dangers.
As we react easily to some subjects that trigger fear, those are the subjects that easily get promoted first. It gives a biased view of the situation by giving a lot of visibility to some news that are very improbable (plane crash, terrorism, bear attack, etc).
The size instinct
A single number can give a wrong impression about the relativity of the reality. For example, looking at the absolute number of dead babies can gives the impression that it's a lot (a few millions per year), but comparing that to the total number of babies that get born every year or how it evolved on the last decades shows that it's not that much.
We need to be careful with absolute numbers. A good way to prevent any over reaction is to either ask for another number to compare to or to compute a proportion out of it.
A usefull rule is the 20/80 rule. Quite often, 20% of the items is making up to 80% of the total. Considering a budget, just looking at the 20% most important items often covers up to 80% of the total budget.
The generalization instinct
Generalizing and categorizing things allow us to act faster and wiser most of the time. But it can also lead us to bad decision or wrong knowledge if the categories we use are not correct. To prevent this over generalization it's a good habit to question the categories we use: what other categories can be similar or opposed to this one, what are the differences and similarities between them?