Superstition of "blood type"

Some people think that ABO blood group distribution determines a nation's race and even nationality, but this statement cannot stand scrutiny and has no scientific basis. As long as you carefully study the blood type distribution of all kinds of people in the world, you can know its absurdity. At first glance, different "races" do have their own blood type frequency characteristics. For example, Europeans have less type B blood, Asians have more type B blood, and almost all Native Americans have type O blood. But this is a predefined race, and then look for its blood type distribution characteristics. If we carefully observe the situation of people in different areas within each "race", we will find that their blood type distribution is very different, but similar distribution can be found among groups belonging to different "races" For example, the difference in blood group distribution between Beijingers (O=29%, A=27%, B=32%, AB= 13%) and Guangzhou people (O=46%, A=23%, B=25%, AB=6%) is much greater than that of Japanese people (O= similar) It can be seen that races cannot be divided by blood group distribution. In fact, it is impossible to divide races by any genetic characteristics, and "race" has no biological significance.

Many serious Japanese psychologists have studied the relationship between blood type and personality and found that there is no correlation, or the correlation is very weak. The latter is considered to be self-realization due to the influence of blood type: because they believe what kind of personality their blood type should have, they unconsciously demand themselves by such standards. Some western psychologists have also studied the relationship between blood type and personality and reached similar results. In the personality test, after testing more than a dozen items, it is found that one or two items are significantly related to blood type, indicating that the results may appear randomly, but they are not really related. Using another group of people to investigate will get different results, which shows that this is indeed a random event.

To take a step back, if there are really many surveys that prove that there is a significant correlation between blood type and personality, can it be concluded that blood type determines (or affects) personality? I can't. Correlation itself cannot be used to prove causality. If the mechanism of action cannot be found or a reasonable explanation cannot be given, then this correlation may be false. In countless things in the world, it is easy to find the connection between two things. The reason of superstition is to regard seemingly related things as cause and effect. Blood group superstition can not only find any basis or reasonable explanation in biochemistry and genetics, but also runs counter to known knowledge. ABO blood group is determined by surface antigen of red blood cells. Because there is a brain-blood barrier between the brain and blood vessels, blood can't flow into the brain tissue, so blood group antigens can't touch the central nervous system, so they can't affect personality. Some advocates of "blood group identification" admit that blood group antigens or blood group genes cannot directly affect personality, but they think that other unknown genes related to blood group genes can determine personality. If there is such a gene, it must be one or several genes adjacent to the blood type gene, which can be linked together in inheritance. At present, most geneticists believe that genetic factors can affect personality, but these factors are extremely complex, involving the interaction of many genes, and it is absolutely impossible for one or several genes to decide by simple genetic methods. So this excuse is also untenable.

Advocates of "blood typing" also try to find evidence from the perspective of human evolution. According to them, type O is the most primitive blood type, so type O retains the characteristics of primitive people and has primitive vitality. Type A evolved from type O in areas with complex terrain and narrow vision, such as forests, mountains and hills. In order to adapt to this complicated living environment, Type A people have strong self-control ability. Type B evolved in grassland, desert and other areas with broad vision, and developed a free and rambling character. The study of molecular genetics subverts this evolutionary picture. In 1990s, three blood group alleles and their variants were cloned and their sequences were determined. Comparing these blood group gene sequences, we can know that gene A is the oldest gene, and both gene O and gene B are mutated from gene A successively. According to calculations, this happened millions of years ago. In other words, human ancestors had three blood group genes and four blood groups from the beginning.

It can be seen that these widely circulated "mysterious phenomena" are not mysterious, and there is no conclusive evidence to prove that they are real. Scientific research must be skeptical, based on evidence, using logic as a tool, not trusting He Qixin's statement, and accepting any bold conclusions easily. The more sensational the proposition, the more we should ask: where is the evidence? Is it logical? The evidence accepted by scientific research institutes must exist objectively, not subjectively; Strict control conditions must be met, such as control and double-blind principle (researchers and subjects do not know each other); Must be repeatable and independently verifiable; It must also conform to the law of probability and statistics. Supporters of pseudoscience often claim to have evidence, and they often list all kinds of evidence in their works, but their evidence standards do not meet the norms of scientific research. They take hearsay, anecdote and coincidence as evidence, which is not allowed in scientific research. We must also know that what we see is not necessarily true. Some people believe in mysterious phenomena because they have personal experiences, such as seeing UFOs or special performances. Others don't believe in mysterious phenomena, claiming that they won't believe them unless they let him see them with their own eyes. They all made the mistake of trusting "seeing is believing". When the human brain processes external information, it has undergone certain processing. The external world we see is actually a processed "virtual world", so we are prone to all kinds of hallucinations, and hallucinations are more likely to appear under the intentional or unintentional induction of a specific environment. Even if the unexplained event you saw really happened, it is not necessarily a mysterious event. If you see a UFO, it is probably a known UFO or other natural phenomenon, but you just don't know it. Remember: what you think can't be explained is not necessarily what science can't explain. We must also remember that authoritative words are not evidence. People tend to believe in authority, and propagandists of "mysterious phenomenon" are well aware of this and often quote authoritative words as evidence. But the authority in one field is not the authority in other fields. If a famous mechanic expresses his views on a mechanical problem, it is worth listening carefully, but when he praises "human science" against the mainstream of science, it is not more worthy of our attention than an ordinary person. Even the authoritative words of our bank cannot be used as scientific proof. No matter how great the authority is, it will make mistakes. Whether a scientific theory is established depends only on whether there is sufficient evidence, not what scientists say.

Judging whether the evidence is conclusive usually requires professional knowledge and training, which most people do not have. But if we can master the principle of scientific rational thinking, even if we lack the ability of specific analysis, we will not be easily confused by a specific mysterious phenomenon. When both sides lack evidence, these principles of rational thinking also help us to judge which side's point of view is more reasonable, more likely and more acceptable.