Is it reliable to judge people's hearts by reading hand prints?

Personally, I think it is not reliable. For example, national team swimmers have been training in the swimming pool all day since childhood, so their hand prints are not obvious. So how should they view their own heart or destiny?

There are not many modern people who really believe in fortune telling, and everyone regards it as the talk at the dinner table at most. But there is one exception to fortune telling, that is, reading palms, because many scientists are also studying this problem. According to statistics, in recent 20 years, more than 400 palmistry papers can be retrieved/kloc-0, and all of them have been published in regular journals.

The palmprint here refers to the ratio of the length of index finger and ring finger, hereinafter referred to as 2/4 finger ratio. It was a German anatomist who first discovered that there was something fishy about this ratio. He wrote for the first time in the 1970s of 19 that there was a gender difference in the ratio of 2/4 fingers, and men were smaller than women. But after the paper was published, it didn't cause any repercussions, and it soon sank into the sea.

Professor John Manning of Swansea University in England first made this word a household name. In 1990s, he cooperated with a fertility clinic in Liverpool to study the relationship between fetal left-right symmetry and hormone content in uterus. He vaguely remembered where he had seen the 2/4 finger ratio, so he took advantage of his position to measure the 2/4 finger ratio of a group of local people's right hands in Liverpool. The results show that the average value of women is 1 and that of men is 0.98, which is really a very small difference.

Professor Manning also measured the testosterone content of male customers and found that the lower the proportion of 2/4 fingers, the higher the testosterone content. This result seems to explain that the reason for the difference in the ratio of 2/4 fingers is androgen. He also measured the proportion of children's 2/4 fingers, and found that the proportion of two-year-old children's 2/4 fingers can already see the gender difference, indicating that the influence of testosterone must have begun in the womb.

1998, Professor Manning wrote a paper about this discovery, which immediately caused a sensation after its publication. Humans are keen on fortune telling. Cranial and facial fortune-telling was once very popular in Europe, but the Japanese invented blood type fortune-telling and it was also popular for some time. These are the physiological characteristics of the human body, which sounds more reliable than a birthday. Unfortunately, follow-up studies have proved that these fortune-telling methods are not reliable, and public interest has gradually disappeared.

The 2/4 finger ratio method is also used to measure people's physiological characteristics, and the measurement is convenient and simple, and the results are clear, and the scientific reason behind it seems to be quite reliable, so this method has quickly become a hot topic in the scientific community, ranging from the incidence of various chronic diseases to different personality characteristics. Sports circles also use it to screen athletes, and several papers prove that 2/4 fingers are more talented than young people.

Even the archaeological community has come to stir it up. Someone has specially studied the handprints left by prehistoric humans on the cave walls, hoping to calculate the gender of the handprints owner through the proportion of 2/4 fingers.

So, is palm reading really reliable? Wait a minute! Mitch Leslie, a senior American popular science writer, published a summary in the magazine Science published on June 7, 20 19, pointing out three doubts about palm reading.

First of all, Leslie collected many related papers and found that the ratio of 2/4 fingers varies greatly among different races, which is far greater than the gender difference, which shows that the genetic background of fortune tellers greatly affects the measurement results. In contrast, the relationship between 2/4 finger ratio and sex hormones is probably not as big as everyone thinks.

Secondly, because it is too difficult to extract fetal blood, so far no laboratory can directly compare the relationship between fetal testosterone concentration in uterus and 2/4 finger ratio, so we can only find indirect evidence through animal experiments. A laboratory at the University of Florida has done experiments on mice, which proved that the concentration of testosterone in uterus is indeed related to the ratio of 2/4 fingers of mice, but this conclusion was quickly denied by similar experiments in another laboratory.

Thirdly, some biostatisticians believe that any research method that takes a certain proportion as a trait index is unreliable because it is easy to ignore the influence of other factors. For example, Douglas Culan-everett, an American biostatistician, once pointed out that the reason why men have less than 2/4 fingers is probably that men's palms are bigger than women's. When a person's hand grows bigger, the ring finger is likely to increase more than the index finger. As a result, the ratio of the two fingers has changed subtly. When Douglas Culan-everett used mathematical methods to eliminate the influence of palm size, the differences between men and women disappeared.