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  • "Hayashi sensei ga odoroku, hatsumimigaku!"

  • This is Hayashi Osamu, a cram school teacher who became famous for a commercial in which

  • he says "ja itsu yaru kaima desho!"

  • That's easy for him to say because Hayashi Sensei here is blood type O and as we know

  • from the 2013 anime "ketsuekigatakun" orBlood type kun,” blood type O people have great

  • focus and can stay up all night studying.

  • You see, in Japan, blood types are sort of like zodiac signs.

  • Many people believe that blood type affects personality and can determine things like

  • the compatibility of a marriage partner.

  • And, this idea has been widespread since at least the 1970's when journalist Nomi Masahiko

  • made it popular.

  • Blood type is more likely to be brought up by women when on the topic of romance, but

  • it's not uncommon for blood type to appear in the media and many other places.

  • This is famous singer Nishino Kana's 2015 song about blood type A people.- “Datte

  • watashi A gata da shi, yappari are kore to shinpai…”

  • One Japanese television show aired an experiment to see how kids would react when a “substitute

  • teacherdropped a vase that the kids were told was very important.

  • They saw that blood type A kids right away told on the substitute teacher, type B kept

  • the secret, type O also told on the sub, and AB promised to keep it secret but then ratted

  • the sub out anyway.

  • In 1990 the Asahi newspaper reported that Mitsubishi Electronics created a small team

  • composed entirely of blood type AB people, thanks to theirexcellent creativity and

  • planning skills".

  • In 2011, ex-Minister Ryu Matsumoto, famously conducted himself in an unprofessional way

  • that led to his resignation.

  • He blamed the rude behavior and abrasive remarks he made towards two governors on the fact

  • that he was blood type B. "B-gata de tanrakuteki na tokoro ga atte" That same year, an issue

  • of Asahi Newspaper talked about how some new graduates were worried that they were being

  • discriminated against during hiring processes for being blood type B.

  • It's not particularly common, but people can sometimes be asked what their blood type

  • is during a job interview, and on some companies' job application sheet, there's even a field

  • to fill in your blood type.

  • One twitter user wrote in 2015 that one of his work superiors said thatblood type

  • O people are usually irresponsible so I don't want to hire them.”

  • Now let me be clear that I'm not trying to present this as a big societalproblem

  • - the point of these examples is simply to illustrate how widespread the concept is in

  • Japan.

  • According to data from 2016, somewhere around 40% of Japanese people believe that blood

  • type contributes to your personality, but what was most surprising to me was that: According

  • to a 2017 survey from an online community exclusive to doctors called medpeer, 38% of

  • doctors thought that blood type affects personality.

  • Let's first take a quick look at the history of this.

  • In 1901, Austrian Physician Karl Landsteiner discovered blood types and we now can type

  • blood based the antigens on the blood cell.

  • Simply put you are A, B, AB or O depending on if you have A antigens, B antigens, both

  • antigens or neither of the antigens.

  • By the way, ABO is just one of many blood grouping systems, but it's what we'll

  • focus on for this video.

  • In 1910, German scientists Ludwig Hirszfeld and Emil von Dungern demonstrated that blood

  • type is an inherited trait, which was recognized as a huge milestone for human genetics.

  • Around this time, it was found that Japan had twice as many blood blood type B people as did Europeans.

  • Emil von Dungern made the baseless and unclassy comment that blood type B people, and therefore

  • Asians with their higher percentage of blood type B people are inferior.

  • Other researchers including Ludwig Hirszfeld had also made negative comments about blood

  • type B people.

  • This inflammatory commentary is what caused professor Furukawa Takeji to begin investigating

  • how blood type affects personality.

  • He wanted to prove that there is nothing wrong with the character of blood type B people.

  • He started his work by analyzing 11 of his relatives.

  • He found that blood type A people were shoukyokuteki which translates toinactive,” orpassive.”

  • The blood type B and O people were sekkyokuteki which meanspositive,” orassertive.”

  • This encouraged Furukawa to go on and look at colleagues and students as well, investigating 319 more people.

  • His results were presented in a 1926 paper titledResearch on Temperament due to blood

  • typehe came up with these traits for each blood type:

  • Then, In 1931 Furukawa published a sensational article in the famous economics magazine jitsugyounonihon

  • titled: "Astonishing new discovery---you can understand career and marriage compatibility

  • through blood type" But, by 1933 the Japanese Society of Legal Medicine said that there

  • was no relationship between blood type and personality, criticizing Furukawa's statistical

  • methods and dismissing his findings .

  • Public interest in the topic remained for a while, but eventually fizzled out.

  • Then, about 40 years later, interest in blood type boomed again thanks to journalist Nomi

  • Masahiko's bookBlood Type Anthropology,” with the subtext: “Become happy by analyzing

  • your personality.”

  • In the book he pointed out that a majority of the post war Japanese prime ministers were

  • blood type O and that many successful baseball players from Japan and Korea were blood type

  • O or type B.

  • In Nomi Masahiko's 1978 bookNew Blood Type Anthropology,” he discusses some data

  • from that same year - 1978, from the AIU insurance company.

  • After looking at 1374 people involved in car accidents across 3 months, they found that

  • those with blood type O were significantly more likely to be involved in an accident

  • and blood type A people were less likely to be in an accident.

  • Blood type O people made up 5% more than expect of the accidents, and blood type A people

  • made up 4% less than expected.

  • Initially, this data might seem pretty convincing.

  • But several years later, in 1995, the story was flipped.

  • Type O's were exonerated and now type A's were the bad guys.

  • 3234 accidents in Ibaraki across two months showed that type A people were much more likely

  • to have a car accident and type O people were much less likely to have one.

  • Despite this inconsistency with the 1978 data, conclusions were even made about which blood

  • type is more likely to have what type of accident, as is illustrated in this easy to understand

  • comic.

  • Just this year, 2018, Takeda Tomohiro published a book titled: “It's really amazing!

  • Blood types.

  • The new truth can be seen from statistics.”

  • In the chapter titledThe mystery of No type A sluggershe points out that all

  • of the top ten Japanese home run batters and top ten batters with the most hits are either

  • type B or O.

  • This might sound like impressive data, "Kore chotto hottokenai data desu ne."

  • But then again, this is looking at only 20 people.

  • When you look at the distribution of blood types across the 786 players in the 12 teams

  • of the Japanese pro baseball league, it is hardly different from that of the national

  • blood type distribution.

  • Let's look at some science on what we're confident that blood type does have bearing

  • on.

  • There's a lot of research showing blood type does affect your health in several ways.

  • But

  • Blood type O's get most of the perks.

  • They are less likely to get pancreatic cancer, are less likely to get Malaria, are less likely

  • to get diabetes and are less likely to develop cardiovascular disease and cognitive decline

  • in old age.

  • Type O's can thank lower levels of von Willebrand factor, a blood clotting agent for their protection

  • against heart disease and cognitive decline, but this also means they are more likely to

  • die from severe trauma.

  • You may have heard of the bookEat right for your type” - "Now did you ever think

  • your blood type has anything to do with your diet?

  • Well this doctor says that it does."

  • author Peter D'Adamo claims that your ticket to good health is eating in a way that is

  • suitable for your blood type.

  • He provides several lines of reasoning to back up his claims which I may discuss in

  • another video, but this blood type diet of his seems to be like the diet version of the

  • Barnum effect.

  • The barnum effect is where someone will be given a fortune or description of their personality

  • based on their star sign or blood type and the person may say it sounds very accurate-

  • it sounds just like them.

  • "I can't believe he analyzed me so accurately."

  • "It does feel actually so personal, it's actually quite hard for me to share."

  • "It's kind of astounding.

  • I've always believed in something like it, but it also shocks me because I didn't think

  • it would work so well."

  • But in reality, the description was vague enough to where it could have applied to anyone.

  • "Yea, I'm afraid you have all got the exact same reading."

  • A 2014 study found that the diets found inEat right for your type” - the blood

  • type A diet, AB diet and O diet provided benefits like lowered BMI, waist circumference, blood

  • pressure, triglycerides and insulin, ...but it didn't matter who followed which diet.

  • You could be blood type O and still get the benefits from a blood type A diet.

  • However, D'Adamo claims thatStudies have shown that Type O has a stress response

  • that centers on fight-or-flight.”

  • He explains that the neurotransmitter dopamine is converted into the neurotransmitter norepinephrine

  • by an enzyme called dopamine beta-hydroxylase, and that blood type O people have higher levels

  • of DBH, so they are prone to anxiety from increased levels of norepinephrine.

  • Higher levels of norepinephrine apparently also causes a tendency towards anger and aggression.

  • Hence, this is why he recommends type O people to do vigorous exercise and eat a lot of protein

  • because that will block the enzyme DBH.

  • In the book, there are no reference numbers next to his claims, andAppendix G: The

  • Scientific Evidencedidn't have any information on where he got this dopamine beta-hydroxylase

  • idea, but I went ahead and looked into it and found a paper by a Donna Hobgood under

  • Medical Hypotheses

  • She explains that the gene for the enzyme we just discussed - dopamine beta hydroxylase

  • is on chromosome 9q34 and is in tight linkage disequilibrium with the ABO blood typing gene.

  • This might have been what one of the Japanese doctors in the earlier mentioned medpeer survey

  • was referring to when he said that the reason he believes blood type is related to personality

  • is thatHe had heard that the gene for blood type and personality factors are close

  • to each other on DNA.”

  • Hobgood says in her paper thatlow activity DBH would relate to impulsive behaviors while

  • high activity DBH would relate to persistent behaviors.”

  • Then, in 2015, inspired by the hypothesis presented by Hobgood, Japanese researchers

  • investigatedABO Blood Type and Personality Traits in Healthy Japanese Subjects.”

  • The results of the study showed significant differences in persistence scores, showing

  • that subjects with the blood type A allele were more persistent.

  • Though the authors were careful to say that this should be considered preliminary results

  • and that this data are inconsistent with several other previous studies.

  • In contrast, a 2014 paper looking at 10,000 people from both Japan and the U.S. found

  • that blood type explainedless than 0.3% of the total variance in personality.”

  • The paper is titledNo relationship between blood type and personality: Evidence from

  • large-scale surveys in Japan and the US

  • So, we're hardly at a point where we can make any worthwhile conclusions about a person's character based on their blood type.

  • Now, With all this said, couldn't there be something to this blood type personality thing?

  • After all, the reason some people get invested in this idea is because they really identify

  • with the description for their blood type.

  • But, that sounds a lot like the Barnum Effect.

  • And, another factor in this could be that it's an example of a self fulfilling prophecy

  • - if someone is often told from a young age that they must be the unique and artistic type because they are blood type AB, then they might start to view themselves as unique and artistic.

  • Or, if you have a giant “B” stuck to your shirt, you might act a little more like a type B person.

  • But then again, Maybe the type A blood in me is making me overly skeptical.

  • While it's hard to actually make use of this information about blood type, hopefully this

  • was a decent exercise in critical thinking.

  • If you want to further develop your critical thinking, then I really recommend checking

  • out out Brilliant.

  • It's a problem solving website that teaches you to be more analytical.

  • They take complex concepts, break them down into bite sized nuggets, and guide you to

  • think and apply your knowledge, so you can build a framework of understanding.

  • For example, in their Science Essentials course, they explain the story of how Barry Marshall

  • proved that peptic ulcers are not the result of stress and spicy foods, but the bacteria

  • H. Pylori.

  • This is unfortunate for blood type O people as they seem to have a higher chance of getting

  • it.

  • In the course, they use this example to not only explain the concept of empirical skepticism,

  • but also encourage you to think for yourself about why Barry Marshall confidently arrived

  • at his conclusion - so confident that he actually drank H. Pylori to get an ulcer and prove

  • his point.

  • It's good to keep your critical thinking sharp so you can keep yourself safe from flimsy

  • logic like what we saw in the development of the blood type / personality theory.

  • So make sure and check out brilliant.org/WIL/ and sign up for free.

  • The first 200 people that go to that link will get 20% off the annual Premium subscription."

"Hayashi sensei ga odoroku, hatsumimigaku!"

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