For nearly all of the first 40 years of my life, I had the habit of biting my nails. I’ve stopped now for just over a year (I don’t think they’ll ever quite return to normal though, because of the damage of so many years’ severe cropping - the nail beds themselves are quite short).
Anyway… I have recently acquired a new habit - one that I didn’t realise I was doing until someone commented on it. I’ve been tapping/drumming the fingernails of my middle two fingers of my right hand on the desk while thinking about stuff at work.
I happened to notice that the nails on those two fingers are longer than all the others - not only that, but they’re uneven - because the nail beds appear to be longer (that is, extend further) on one side of each of the two fingers - the side that bears most of the impact, due to the slight tilt of my hand when tapping.
So… I did already google this, and did find a number of sites where it was claimed that tapping the fingernails on a hard surface can encourage them to grow faster/stronger, but none of these sites quite seemed to cut the mustard, in terms of academic rigour.
They do argue some not-implausible mechanisms (mostly increase of blood flow), and I think I remember reading about some other experiments relating to vibration causing accelerated growth (in plants, I think).
So what I’m looking for is the serious answer to this - does anyone know if there has been any proper research into this topic?