Scientists Wonder What Fingerprints Are For

Hugh Pickens writes "The BBC reports that scientists say they have disproved the theory that fingerprints improve grip by increasing friction between people's fingers and the surface they are holding. Dr Roland Ennos designed a machine which enabled him to measure the amount of friction generated by a fingerprint when it was in contact with an acrylic glass at varying levels of pressure. The results showed that friction levels increased by a much smaller amount than had been anticipated, debunking the hypothesis that fingerprints provide an improved grip. Ennos believes that fingerprints may have evolved to grip onto rough surfaces, like tree bark; the ridges may allow our skin to stretch and deform more easily, protecting it from damage; or they may allow water trapped between our finger pads and the surface to drain away and improve surface contact in wet conditions. Other researchers have suggested that the ridges could increase our fingerpads' touch sensitivity."

Comments

Maybe they're for nothing?

[Karganeth]

If it takes an equal amount of resources for the body to grow a finger without fingerprints then it makes sense that they not meant for anything. Not everything has to have a purpose.

Re:Maybe they're for nothing?

[maxume]

Or a population of primates that happened to have fingerprints became dominant for some other reason.

It is often the case that an environmental shift makes an existing trait advantageous (that trait may have been meaningless in the previous environment), rather than an advantageous trait arising in a static environment.

Re:Maybe they're for nothing?

[funkatron]

If we have fingerprints, it's genetically possible to be born without, so it's very likely that that mutation existed in the history of evolution, and that one of those specimen procreated, creating that fingerprint-less type of monkey/man.

I would actually question to what extent this is a possibility. Human skin has all sorts of textures and patterns, most of which we don't treat with any significance. It may be that smooth skin is actually difficult to produce by biological processes. This is a possibility that should at least be considered.

Re:what do you think?

[malchus842]

Throughout history, there have been lots of questions that science has not been able to answer. But science is not static. Over time, it has been able to answer more and more questions and close more and more of the 'gaps.'

For any theist, the 'God of the Gaps' defense is pretty weak. Just because we don't understand something doesn't require a God (or gods) to explain it.

This is not a rejection of theism, but simply a comment on science - just because we don't have an answer now doesn't mean we won't have an answer in the future. And not having an answer does not imply that there is a (or many) God(s).

Re:Primates

[Anonymous Coward]

There are probably multiple reasons for the fingerprints.

The skin has to be both flexible and durable at the same time, and gripping on moist surfaces should also be safe.

A flexible skin is also allowing for better dexterity and a finer resolution when sensing surfaces.

Many things

[bytesex]

More grip, larger surface, which means more flexibility, more nerve-endings - more sensitivity, better warmth-exchange, 'folded-up-ness', which means more protection from wounds, easier to clean (like footprints, the mud just falls out), 'little bits that stick out' - meaning more sensitivity again.

Bad science or bad journalism?

[YourExperiment]

With articles such as this, it's hard to tell whether we're being subjected to bad science or bad journalism. Both the summary and TFA quite categorically state that the "myth" of fingerprints being used to improve grip has been disproven. They then go on to describe how this experiment tested whether fingerprints helped when grasping an extremely smooth surface, and found out that they didn't (well okay, actually they did, but not by very much).

Finally, some alternate hypotheses as to why fingerprints evolved are posited, the first of which is: they may improve grip on rough surfaces. Not acrylic glass or anything, but those other kind of surfaces - you know, the type that actually occur in nature.

I'm pretty sure I don't know much more now than I did before I read the article.

Re:Primates

[stonewallred]

most evolutionary features get kept that do not kill the person/animal having it, and which does not put it at a disadvantage in reproducing. There are many more evolved features that do nothing that have been kept than you think.

Re:what do you think?

[jonbryce]

"I believe there is no God" is as much a statement of faith as "There is no God but Allah, Muhammad is his messenger". There is no scientific evidence to prove or disprove either statement.

Re:Primates

[Reziac]

Exactly -- why does it have to be for any particular use? More likely it's just an artifact of how skin develops. People forget that many traits didn't evolve for a specific purpose, but rather, were random mutations that were not selected against, becauee they did the species no harm.

The whole question also shows a profound ignorance of the rest of the animal kingdom:

Dogs have noseprints that are as unique as fingerprints (and in fact are legal ID for dogs in Canada). Why is this? Probably no reason at all, other than quirks of individual cell layout in the skin layer.

Chickens have similar uniqueness in the surface of their combs. Why? Likewise, probably no reason, other than it's just a trivial quirk of how the skin cells piled up in a given individual.

Re:what do you think?

[Fribulator]

Although that seems like a good idea at first, if the treatment was powerful enough to remove his fingerprints, it could have caused some nerve damage as well, which could cause his diminished sensitivity. However, if he (and other such people) were to submit to tests and scans and general research, they would surely prove helpful in deciphering the mystery of the fingerprint.

Re:Primates

[Reziac]

Dogs often use their noses like a jack-hammer... the nosepad is not particularly sensitive to touch. If your dog is too wiggly to get a noseprint (which one does with a paper-pad and roll-on ink, much as one would footprint a baby), chances are the dog needs more training, and you need lessons on how to be the pack leader, too.

(Disclosure: I am a professional dog trainer. :)