Review of the world until yesterday by Jared Diamond

Up until a few tens of thousands years ago all humans lived in bands consisting of up to a few dussin people. Thus during almost our entire evolutionary past we lived in an environment very different from the one we live in today. To understand the evolutionary pressures that have shaped our behavior and our cognition we need to look at the way our ancestors lived. This is of course more or less impossible because written history did not appear until very recently. However, there are people alive today, who live in a manner we think is very similar to the way all humans used to live. This book is about these peoples. How do they live and think, what are the similarities and differences between us and them? What can we learn from the way they live?



This book shows that the life of our ancestors was not, as some people (especially Disney employees) like to think, all romantic and in harmony with nature etc. Personally I would never switch my life in a civilized western nation for a life in the jungles of New Guinea, and I think that any informed person would be inclined to make the same choice. The life expectancy is about half of what I have now. They are also much more likely to be murdered because crime rates in such societies is extremely high compared to any state nation. Also they have no Wi-Fi, and that would suck too.

In short, life was not better before, it is better now, much better. With that said, there are many lessons to learn from traditional societies and lifestyles. Jared Diamond in “The world until yesterday” goes through many aspects of life, including but not limited to health, crime, diet, child rearing and care for the elderly. Consistently, there are things that we do better in modern western societies and to his credit Diamond points this out. However, there are also lessons to be learned from people living in traditional societies.

The justice system is good example. Crimes in traditional societies are dealt with by the community. There are no absolute laws. For example, murder is sometimes seen as justified and therefore not punished. If someone accidentally causes the death of another person then it may be sufficient for the perpetrator to pay sorrow money to the victims family. Western societies on the other hand see crimes as committed against the community and a perpetrator cannot walk away even if the victim forgives him (yes it is usually “hims”). What lessons can we derive from this. It is probably the case that we can learn things from traditional societies about finding common ground between perpetrator and victim. Grudges are usually resolved one way or another. However, in traditional societies it is also much more common that people take justice into their own hands, which can and do have fatal outcomes.

In some areas the conclusion that progress have been made is inescapable. One perhaps unexpected example of this is wars. The first time I heard about the relative casualty rates in traditional and modern “total” wars I was rather surprised. I had always thought that the second world war was the worst war in the history of mankind, however, if one compares the casualty rate in the second world war with the casualties in wars between traditional tribes it is actually much higher in the latter. In some traditional wars the casualty rate reaches one percent of the population annually whereas Germany and Russia (the two worst hit nations) saw casualty rates of about 0.16 percent annually during the second world war. In other words, you would be much more likely to die in a “traditional war” than in WW2… One factor here is also the fact that whereas children in western societies are taught that killing is wrong and often feel bad after having killed another person (even in wars), children in traditional societies are sometimes taught to feel pride upon killing an enemy. Taking into account wars as well as violence that occurs between wars, it is crystal clear that we are much better off in our modern world. As Jeff Niehaus, who was teaching developmental psychology at UCSB once said, downtown Chicago is actually really peaceful if you compare it to traditional societies.

I

guess that it is clear to the reader that I feel quite fortunate that I live in a modern society and not in the jungles of New Guinea. In a few respects however the sometimes cannibalistic tribes outperform us. One obvious example is language. An average New Guinean knows five languages, which is rather impressive. I personally know only three and I think that is probably better than the average person in modern societies. Diamond argues that we should try and preserve languages which are otherwise bound to go extinct. I was not entirely convinced by his arguments. I accept that bilingualism is associated with performance on other types of tasks, delayed dementia etc, however, I also think that it would be desirable if communication between different peoples of the world was easier. Maybe there is a compromise between extinction of all languages except english (or chinese), and the ability of people to talk to each other (I’ll have to return to that topic).

In one of the last chapters Jared Diamond compares the health of people in modern and traditional societies, with mixed conclusions. Once again it is absolutely clear that we live longer in western societies. This ought to be problematic to explain for those who like to claim that a “natural” lifestyle is preferable and more healthy in general. Even though we are using more and more “chemicals” (everythings is chemicals really), we also live longer and longer. If chemicals kill us, then why do we live longer? In some respects our modern lifestyle is not so good however. We do consume too much salt and sugar. Diabetes is pretty much unheard of in some traditional societies, and high blood pressure (which occur if we eat too much salt), is also extremely uncommon. So one lesson we can learn is to eat less sugar and salt.

There are many more interesting topics in this book. One that I found particularly interesting was child rearing practices where people in traditional societies spend much more time which their kids and have much more skin to skin contact, an approach I personally do believe in to a certain extent. I also liked the discussion about treatment of the elderly which ranges from leaving them to die when they go dement (this was the practice of Swedish natives), or killing them when they are no longer of any use, to chewing their food for them when they have no teeth (yuk).

Overall I liked this book. It was 20 hours well spent although I think Diamond could have excluded certain parts that were personal and not so interesting if you are not extremely interested in Diamonds personal life. However, I did learn a lot that I did not know before and it gave me some new perspectives and it even made me want to change a few things in my own life. Above all however, the book reminded me of the privileged life I live. I live in peace. I have a family that I love (and I am under the impression that they like me too). I have a stimulating job that I like, and I am able to explore the world in a way that would be completely unimaginable to 99.99% of all humans that have existed on this planet. I really did win the lottery in the most important sense. Lucky me =)

Benefits from playing action video games

I just finished reading a recent review by Dapne Bavelier about the benefits of playing action video games. This review does not address the controversial issue of whether video games cause people to become more violent or not (I am personally on the fence on that one).

Rather, this review focus on the effects on more basic perceptual processes, and how playing video games affects these abilities. All this is put within a "learning to learn" framework. That is, will playing action video games help you find patterns or gain knowledge when you are not playing video games as well.

The pattern is very clear here. Video games will help you in a number of different ways. People who play action video games (sim city or civilization won't do), are faster at identifying objects, without making more errors, there are not as easily distracted by irrelevant stimuli, and they have greater contrast sensitivity. It seems as though video games enhances eyesight in general.

There are also substantial benefits in certain cognitive functions. People who play action video games enhance their ability to perform mental rotations (ex determining which 3D shape matches another 3D shape). Mental rotation in turn correlates with improved mathematical skills. Multi-tasking is another cognitive function that is improved in video game players.

Significant improvements have also been seen in decision making and reaction times. These factors may determine whether you brake in time to prevent a traffic accident or whether you die.

Thus in general, playing action video games improve a broad range of perceptual/cognitive abilities which probably helps the individual find relevant information in the environment, even though that environment does not involve war.

The objection which I am sure that some of you have thought of already is the classic "correlation does not equal causation". Maybe people who are good at all of these perceptual/cognitive tasks to begin with like video games more and therefore play more. Indeed, it you are slow, you get killed a lot in many of these games which can be very discouraging (I have played a little bit online and it sucks when you get shot 30 times over by a ten year old).

Researchers of course anticipate this objection and therefore conduct controlled studies. For instance you can take a random group of student with equivalent video game experience and then pay them to play either call of duty or civilization (a turn based game) for a few hours per day for a week or so. Differences between these groups after the intervention are probably due to the different treatments. Such controlled studies support the conclusions above, video games really do improve perceptual/cognitive functions.

So depending on whether you think action video games will increase aggression (like I said, I think the jury is still out on that one), if your child is playing violent video games and still not missing out of school etc, then you might even want to encourage this.



Bavelier D, Green CS, Pouget A, & Schrater P (2012). Brain plasticity through the life span: learning to learn and action video games. Annual review of neuroscience, 35, 391-416 PMID: 22715883