If you can't, then you were either born well into the second half, or you learnt keyboard skills at a very early age.
In my case the once-hard skin is softer than it was, but there is still a shininess and a baldness lacking from my other fingers. The digital disfiguration is not congenital, nor is it the sign of youth misspent in billiard halls. It is a legacy from the years when writing tools were not so finger-friendly.
There must have been a direct correlation between the length of time spent in school and the texture of the callous. The correlation could even be extended to what kind of course a pupil did and what age they left school.
There could not have been many junior secondary pupils in the 1950s required to write out copious teacher's notes on Il Pensoroso or L'Allegro, describe the major battles of the Peninsular War, or replicate the columns of useless data required by an experiment in volumetric analysis. In my case the implements used went from (don't laugh ) crayon, pencil, pen and ink, smudgy biro, fountain pen, back to pen and ink, and finally to ballpoints that didn't leave the hands looking as if a major vein had sprung a leak.
The worst mess could be made when trying to underline the date with pen and ink or even a fountain pen, and we always had to insert the date at the beginning of an exercise, whatever the subject.
Which was the best way to lay the ruler on the page, flat side up or down? It was a heart-stopping moment as the ruler was lifted, and always a relief if a smooth, clean line remained rather than a quarter-inch thick smudge of Stephens' Blue-Black ink. And rulers were used a lot, even to draw the "equals" signs in the volumetric analysis calculations.
Whatever the implement, and initially it was chalk and pencil (or did we use pens as well?), it was the pressure applied to it during writing lessons in the primary school that started the damage. We would grip the tool with a cramp-inducing intensity, and with gritted teeth already at risk from over-indulging in Cowan's My Sweet chocolate toffee.
In the upper stages of primary you deliberately applied too much pressure on the wooden pens, so that the nib would break off, leaving a neat little double-pronged bident (that's a trident with one less point). This was ideal for scraping initials on the desk, made a highly effective and dangerous missile, and in the hands of the more unscrupulous could do lot of damage in close combat.
A major problem with the pen and ink routine was ensuring there was enough ink on the nib when it was withdrawn from the inkwell. God, all this is beginning to sound a bit Dickensian. Invariably the user shook the pen to check there was enough writing fluid to complete the task in hand.
In the days when sitting in rows was common, this could often result in an uninvited adornment to the apparel of the person sitting in the desk in front.
The introduction of the ballpoint pen, given the generic name "biro" after its French inventor, was a mixed blessing. The gimmicky button at the top gave a satisfying click when it was depressed and there was a certain kudos from displaying a battery of them in your breast pocket like a row of campaign ribbons.
This early attempt to make writing easier and cheaper, a form of literary democratisation, had its downside. As well as dirty fingers and hands, it meant a rough ride from a teacher if there was too much of a mess made on the paper. An even worse fate befell anyone who arrived home with a jacket or blazer stained with indelible ink after a pen had burst open or leaked into the pocket.
We are approaching the end of the calloused finger millennium. I suspect that at the end of the next millennium, or even the next century, the anatomical equivalent for regular writers will be to have their keyboarding fingers a few centimetres shorter than the rest. I can already see my two index fingers beginning to shrink.