BackThe untold story of the little finger
It's easy to see the little finger as an appendage we don't strictly need
PremiumReading about tennis not long ago, I found this interesting tip for improving your serve: don’t grip the racquet too hard. In fact, let your fourth and fifth fingers essentially hang free. Grip the racket only with the thumb, the second and third fingers.
Whoever offered this friendly advice also observed that the great Pete Sampras gripped his racquet that way. Seemed like a reasonable example to emulate, so I tried this. I can’t claim that I served well as a result. But I can claim that I served better—I was able to impart to the ball a little more power, direct it a little more accurately.
Pity is, I have since slacked off on playing regularly, so I don’t know if these improvements will still feature if and when I get back to the court.
But it did get me thinking about matters outside tennis. About my fifth finger, in particular. If it is essentially dispensable in this matter of a tennis grip, does it serve any real purpose at all? You may scoff at my extrapolation from tennis to life itself, but I did wonder. As I write this, for example, I’m raising my glass of gin and orange juice using only thumb and the next two fingers. No fourth, no fifth. My glasses? Thumb and index. Lifting a suitcase? All five, but I could do it without the little finger.
In short, the examples abound, of life without the fifth. No doubt it makes certain things easier, but it’s easy to see it as an appendage we don’t strictly need. Which of course raises the question: why is it there? Why haven’t we evolved to rid ourselves of that finger?
The simple answer to those questions is that I’m taking far too simple a view of the little finger. Perhaps because our thumb is such a unique, distinctive limb, it has been studied far more intensively than the other four fingers, especially the fifth. In fact, there are scientists who have noted that the analysis of the fourth and fifth fingers have often been “limited to examining their length relative to the first digit."
Yet tennis and gin grips aside, the fifth is stronger than you might imagine and has many uses. In fact, there’s evidence that in certain human activities, it is used more often, more heavily, than the thumb and forefinger.
Given that, think about this sentence for a moment: “The fifth digit therefore appears key to (over) 2 million years of (certain) activities, a behaviour that likely contributed to (its observed) anatomy."
And what were these activities that shaped our little fingers over all that time?
According to the paper where I found all the quotes above ("The unexpected importance of the fifth digit during stone tool production", Alastair J.M. Key et al, Nature, 13 November 2019), it’s the production of stone tools.
Ancient stone tools were made of flint, primarily because it’s a stone that is easy to shape, yet maintains a sharp edge and is hard enough to cut or strike with. The tools are produced by a process known as “knapping", used even today to shape flint. A knapper will typically hold a large chunk of flint in one hand, brace it against her thigh, and bring her knapping instrument down sharply on the edge of the flint. If she’s done it right, a flake breaks off the chunk. It has sharp edges, which means it can itself become an arrowhead, or the point on a spear. Meanwhile, the knapper will probably want to keep on hitting the chunk of flint, breaking off still more flakes. Maybe you have a picture in your mind of how the chunk gets shaped in this way, eventually resembling a teardrop with a sharp point and edges. This is your regulation Stone Age hand-axe.
Note that the knapper used both her hands for this job. One, to hold the chunk of flint. The second, to grip the knapping instrument. Relevant to this discussion, she used the fifth finger on both hands.
If you think about it—better yet, imagine yourself doing the knapping—you’ll know how this works. Try holding a fist-sized object without using your little finger. You’ll quickly realize that you don’t really have a reliable grip on it; sometimes you might even put that finger under the object to support it. But even if you don’t do that, you can feel the pressure the fifth finger exerts as part of your grip. In short, that finger plays an important role in supporting it, especially if it is going to be hit with a knapping instrument.
The same applies to the knapping instrument. Take hold of a relatively thick rod about six inches long. Now imagine using that to strike a stone you have in your other hand. Even in the picture that’s in your mind, I’m certain your little finger is holding the rod tight. Again, try holding it without using that finger. It just doesn’t feel like you are holding it firmly enough to be able to deliver a strong blow to the chunk of flint.
In the paper I mentioned above, the authors turn these thought experiments into reality. They observed several “skilled flintknappers during multiple stone tool production procedures". They recorded which of their fingers exerted how much pressure on the objects in their hands. They found what they refer to as a “heavy recruitment of the fifth finger" in these tasks, and a “substantial loading" on it in comparison to the second and third fingers. That is, the fifth finger played an important role, even more so than the index finger and its neighbour, the longest of the five.
So, once our human ancestors started making stone tools about 2.6 million years ago, the fifth finger “could have experienced selective (evolutionary) pressure in response to these high demands" that were made on it.
Yet remember that this is only to do with this tool-crafting exercise. Does that fully explain why the fifth finger has evolved into the deceptively strong, flexible and versatile digit that it actually is today? Were there other influences on the evolution of our hands, and the little finger in particular? After all, our prehistoric ancestors did plenty of other things with their hands too. Three examples are feeding themselves, grooming themselves and others, and using spears to hunt.
Probably not playing tennis, though.
Once a computer scientist, Dilip D’Souza now lives in Mumbai and writes for his dinners. His Twitter handle is @DeathEndsFun.
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