Take a look at the fingers of your hands. There are so many spots or grooves on each finger. Those who watch TV shows have seen CID or CSI national crime at some time. They surely know the identity of the assailant with this groove. This fingerprint is generally considered inevitable as evidence. But many people have no idea about how confident this process is. Our discussion today is about this matter.
Before starting, let's see what the fingerprint is. There are different types of impressions on our fingernails, hands or feet. During the mother's womb, the impression was based on the beginning of our life. Scientists agree that the fingerprint started in 10 weeks of pregnancy. But they did not give any concrete idea about the method in which they took their position on the finger.
The most common idea is that our basal layer grows faster than the other two levels, causing pressure from the external aposematism and the inner dermis level. Due to this pressure, some parts of epidermis crumble into the dermis and form a groove, which eventually becomes as a fingerprint. However, along with skin-level stress, some other effects also work in this case. One of them is blood pressure, the amount of oxygen in the blood, the number of nutrients in the mother's body and the position of the fetus at a particular time.
Different skin and fingerprint structure; source: slideshare.net
Fingerprints were used to identify the first person in the late nineteenth century (in 1896). Sir Edward Henry divided the fingerprints into different classes in 1901. Which gradually spread throughout the United Kingdom and the United States. In 1911, a person named Thomas Jennings was convicted in a murder case based on a fingerprint in America. But at this time, it was largely determined that the fingerprint is the same on the basis of the imagination of the human eye. Computer use started in the 1990s.
Thomas Jennings, the first fingerprint identified; source: gettyimages.com
However, it does not matter that you take a fingerprint in a database and that you will be able to find the culprit right away. The FBI database contains more than 53 million files. According to Michael Winners, head of the Latina Print Support Unit of the FBI Laboratory, it takes at least 2 hours for a print database to match.
Is the uniqueness of fingerprint scientifically recognized?
It is believed that every human fingerprint on the earth is unique. This is a statement from Sir Francis Galton's claim. However, he could not show any scientific document yet to support this information. And now that is considered true. All of the tests that have been done are for a specific population. But the problem is, if you see these results, you might say that there is no fingerprints in the particular population. Suppose you examined the same experiment with a fingerprint of 7.6 billion people around the world, your documents will not be self-contained. Because you examined the impression of living people, but you can not count around 100 billion people who have died in the world. As a result, it is not possible to make a real scientific document.
But scientists have been able to make the decision that this impression will be different in every human case. This imprint may change even with age growth. It has also been found in the study that there is a difference in the part of identical twins or identical twins.
So what does this impression really work in case of catching an accused?
As you watch TV shows, fingerprints and other phenomena are collected by forensic labs. But the matter is not as straightforward as you think. A crime cover is to collect every mark hidden in the front and to determine which ones are usable. Our discussions are now limited to fingerprints. A team expert on fingerprints has expressed that, the impressions they have to work with do not have a good database in them; most of them have a mark or a scratched impression, which in turn makes it difficult to match someone's fingerprint. Stands According to the FBI's Michael Winners, only 26 percent of all printed labs are useful.
Fingerprint sample; source -fineartamerica.com
Moreover, there is no restrictive rule in case of a partial impression. In the case of such a print, it is seen in some specific points whether it matches the mark. Some countries see this matter differently. For example, in Milan, there should be two impressions in 16 locations, in this case, there are only 7 points for Sweden and 12 for Australia.
Partial impression match; source-gautierandcharles.biz
The mark that is marked in the case of a partial impression; source-toledotechnology.org
With the help of digital photography, matching the print is relatively straightforward, but at the end of this work, an experienced person has to look at these signs and decide that the two impressions are the same. If you consider this as an error that has been named Cognitive bias
In one study, five fingerprints give a fingerprint of the experienced people to match with another impression. They claimed that all the impressions they had given were met at one time of their lives. Researchers change the way that they are informed about a criminal. It became astonishing matter when four of the five people changed their mind about their analysis.
In another study, some fingerprints from a group of experts are said that some fingerprints have been arranged from the digital database. They have to consider the truth of that fruit. In this study, it is possible to increase the chances of their imprint if they are at the beginning of the list, likewise the likelihood of matching will decrease if the actual impression is below the bottom of the list.
But this does not mean that the fingerprint of the law enforcement organization should be stopped. They must use, but they must be careful in a certain amount. In that case, there will be no law and order in the law. Researchers have more responsibilities and further refine the process of analyzing fingerprints from lifting. In addition to analyzing the experience, there is a need to keep in mind the issue of cognitive bias. Finally, experts present their opinions on fingerprints, there is no truth.
Feature Image: sciencemag.org