In Japan, you are what your blood type is

Seriously?

Yes unfortunately, seriously. It is even worse than horoscopes in North America, and remember Reagan had white house astrologer. So it is pretty bad. Masahiko Nomi has a science background but no medical background. And in Japan like the west the press often can't (or won't) tell the difference between scienitists in the field and outside the field promoting idea.

This is just about as ludicrous as Korean fan death syndrome.

You left- brainers have about as much sense as a robot stuck in "GO TO 10)" mode. If you weren't so face deep in Issac Newton's asshole, you'd know all about how the different blood types evolved in different historical conditions, resulting in different bodily chemistries, nutrition needs, and even brain function.

Piece of advice: You are loosing grip on reality.

These people are making the future robots. In that case I think the future will be grim. As far as I'm concerned I'll always keep all 4 types for the blood tests.

Mercury_01: Either all of us or just you. I'm placing my bet. There're not only four types of personality, dude.

Of course it's stupid, but every country and every nation has its share of stupidity. As long as it doesn't lead to discrimination in the workplace or in social life it's just another delusion for someone to make money out of.

It was pretty fun to read. And here I was, thinking my mom was crazy for such an interest in horoscopes...

Which surprises me. Horoscopes and these are all just profit making schemes. Whatever made people think that people born in the same month has the same personality and luck?

No, there are not four types of personality, but personalities do fit into those categories. There is truth to this axiom, even through the hype.

Funny how you base your scientific knowledge is based on popularity, "smartk8t" Real smart.

Just keep doing what you are doing people. See where it gets you in about 10 years. You'll be supplanted so fast it'll make your head spin.

Mercury, would you mind telling me why you suspect that an antigenic surface coating on red blood-cells evolved for disease resistance will show some measurable correlation with behaviour or personality?

@Soylent - everything is connected in some subtle way or another. There may be a biological interaction that makes this interpretation valid. Recent research has revealed a lot of seemingly unrelated things interact in vivo. I want more evidence before I loftily decide it's piffle.

@Mercury_01 & SmartK8t - don't feed the trolls or be one.

@Keter - The burden of proof is on the person making the claim. It doesn't work like someone proposes something and we regard it as true until it's disproven.

If this guy thinks that blood types have an effect on personality than he should write a paper on it and have it peer-reviewed. Just writing a book on something doesn't make it real.

Keter - I know, I know; but it's so hard to resist to critize a pseudoscience. But there are the articles you can scientifically speculate about and then there are those you can just say "Wow! That's I don't know.. laughable and so out of place". Ok to not just being percieved as a troll I guess I have to write an opinion smarter than the article itself. Well what about the fact that when a blood transfusion is performed a blood type O is a major donor. That makes your personality spin then. When the first heart transplantions were performed there're thoughts that you'll receive the donor's traits as well or even a feeling for someone else. How about that stupidity.

Its not the blood type that determines personality, you dolts, Its the evolutionary background that comes along with them. Seriously, is there a scientist in the room? You know, Nevermind.

According to some of the more reasonable Western advocates, it's NOT THE BLOOD ITSELF that can determine these things. It's the traits associated within the same LOCUS where the blood type is found (and as mentioned above, their evolutionary background).
In some pigs, blood type is empirically correlated with hair color. In humans, it may be metabolic/digestive, immune/allergic and neurological/stress-response genetic traits.
According to one study, ABOs tend to release differing levels of hormones to the same stress response (ie, Os - more adrenalin, Bs - more cortisol).
There are also differing rates of mental (and physical) diseases among the types.
While these differences hardly justify a horoscope or cult-like following, they could explain some (very) generalized statistical personality differences when the groups are taken as a whole.