What food will mashed potatoes go with?

Ok, now let me ask you a question: how do you determine the causal relationship of things? There is a joke in McDull Story: Mrs. Mcdull told McDull a bedtime story: Once upon a time, a child lied, and one day, he died. Once upon a time, there was a child who studied hard. One day, he made a fortune. Once upon a time, there was a very unfilial child. One day, he twisted his foot. Mcdull said impatiently, mom, I want to sleep. Mrs McDull said that once upon a time, there was a child who went to bed early and got up late. The next day, he died. (Video can be played directly)

Everyone can probably see that the funny thing about Mrs. Mai's story lies in forcibly connecting two things that have no causal relationship and drawing some kind of "educational significance". But in fact, this is a very serious scientific problem: how to determine the causal relationship. Humans have a problem, and they like to habitually associate two things that have happened successively with cause and effect. The former is cause and the latter is effect. This instinct works most of the time: when the clouds are overcast, it is likely to rain cats and dogs and the roads are muddy. These are all causes and effects. But sometimes it is not so correct, and even the opposite conclusion is drawn: when the rooster crows, the sun rises, but we can't take the rooster crowing as the cause of the sun rising-in fact, it is the result. Let's give a more recent example. Now we all know that smoking can cause cancer, but it is not easy to draw this causal relationship. Although previous epidemiological data show that smoking has a high correlation with lung cancer, does smoking cause lung cancer or do lung cancer patients particularly want to smoke? The two sides have been arguing endlessly until 1996 found the carcinogen benzopyrene in cigarette smoke, which solved the mystery.

Let's go back to the problem of stomach pain when crabs and persimmons eat together. Eating crabs, persimmons and stomachache are three things. Eating crabs and persimmons comes first, and stomachache comes last. The ancients naturally regarded the former as the cause of the latter, but it is easy to think that stomachache is not necessarily the result of eating crabs and persimmons together. It may be the result of eating crabs, persimmons or other things alone, or it may have nothing to do with eating at all, but other reasons. In order to find out the causal relationship, we need to establish a control group. Simply put, it is a group that eats crabs alone, a group that eats persimmons alone, and a group that eats both. What is the final truth? In fact, eating crabs alone is easy to have a stomachache, because the carapace of crabs is difficult to clean, hiding evil people and filth. Once it is not thoroughly cooked, it is easy for germs to infect the gastrointestinal tract; Eating persimmons alone will cause stomachache, because persimmons contain tannic acid, which will react with protein in gastric acid to form tannic acid protein, which will stick with pectin and cellulose to form stones, which is called gastrolithiasis. Eating raw persimmons, eating a lot of persimmons and eating persimmons on an empty stomach may all cause stomach pain. Of course, persimmons are as prone to stomachache as crabs, because crab meat is protein, but beef, chicken and eggs all contain protein, and even persimmons themselves contain protein. In fact, as long as you don't eat too many persimmons, don't eat raw persimmons, cook the crabs thoroughly, and you are not allergic to seafood, there will be no problem eating persimmons and crabs together. We don't know which of the above causes caused the stomachache of the ancients, but "crabs and persimmons eat together" has been circulating for hundreds of years.

So besides crabs and persimmons, are other food combinations fake? Because the term "cannibalism" only exists in China, there is no research in this field abroad, but some scientists in China have studied it.

1935, Ji Zheng, a biochemist in China, collected 184 pairs of "Fragrant Family" foods, and selected 14 pairs of foods that are easy to meet in daily life, and made experiments with mice, dogs and monkeys. He and a colleague also tried seven of them. Observe the expression, behavior, body temperature, fecal color and frequency of experimental animals and people within 24 hours, all of which are normal and have no signs of poisoning. Among the "pilgrims" food tested in Ji Zheng, crabs and persimmons, green onions and honey were included. Ji Zheng happened to be one of the oldest scientists in China, and lived 1 10 years old. Recently, the Nutrition Society of China cooperated with the School of Public Health of Lanzhou University and Harbin Medical University respectively to conduct a more rigorous "food" experiment. In the experiment of Lanzhou University, five groups of food combinations were selected and given to 100 healthy volunteers for a week, and no abnormality was found in one group of food. In the experiment of Harbin Medical University, another food combination of 12 was selected, and 30 volunteers were allowed to eat for 3 days continuously, and no abnormality was found.

Since there is no legendary food poisoning, how did the ancients experience it? How did you get down?

-Can words depend on some music?