When Thomas Jennings attempted to flee the scene of a murder in 1910, he was “lucky” to become the first person in history to be caught by leaving fingerprints on a drying railing near his home. Since then, fingerprinting, which is a way of identifying a person due to a unique pattern on the skin, has actively continued to appear as the most important evidence in judicial investigations. But, it is quite clear that fingerprints do not exist for the sake of entering into the general police database. So why does a person have papillary patterns on the skin of the hands and what biological role do they play? Let's try to figure it out in this article.
Fingerprint readers have become common in laptops, smartphones, terminals and other external devices.
Why does a person have patterns on his fingers?
In the course of work on the study of the papillary pattern on the skin, experts adhered to two theories about their biological purpose. So, drawing on the fingers of a person's hands may be needed to improve adhesion to any surface, as well as to enhance sensory perception. For a long time, the dominant theory has been to create better grip thanks to tiny depressions and bumps on the toes, as modern car tires are designed in a similar way. In order to test such a hypothesis, scientists conducted a laboratory experiment to identify functional similarities of finger patterns with the principle of car tires.
According to an article published on the portal Livescience.com, in the course of the experiment, experts pulled a special plate of organic glass through the fingertips, changing the pressure. As it turned out later, the actual contact area was reduced compared to smooth areas of skin, which may serve as a refutation of the theory of creating additional adhesion.
The papillary pattern can play a large role in the sense of touch.
Our fingers are known to have four types of mechanoreceptors or cells that respond to mechanical stimulation and touch. In order to confirm or disprove the theory of an increase in sensory abilities, scientists have studied in detail Pacini's little bodies, which are found at a distance of about 2 millimeters at the fingertips and are responsible for the perception of fine textures and light vibrations.
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For the next experiment, scientists have designed a biomimetric tactile sensor that can detect vibrations, similar to Pacini's human corpuscles. One version of the device was created with a smooth structure, and the second had a raised surface similar to a human finger. In addition, the ribbed surface increased the frequency of vibrations to which Pacini's little bodies are very sensitive. Scientists speculate that fingerprints amplify point vibrations and direct them to sensors under the skin, amplifying fine, detailed sensory information about the surface. The experiment carried out served as an additional factor to confirm the assumptions about their biological function in nature.
Scientists suggest that the process of capturing an object is also associated with our prints. It is thanks to our specific pattern on the fingers that we are able not only to hold the object in our hand, but also to feel the degree of fixation of the object in order, if necessary, to strengthen the grip in case of sliding.
Daria Eletskaya