Anyone who is sufficiently interested to listen to a classical piano performance understands this. The original name for the piano was 'pianoforte', it was a novelty that it could be played soft or strong in contrast to instruments like the harpsichord.
I also don't understand what the breakthrough in this paper is supposed to be. I pointed out to the lead author that velocity-switched multisampling libraries have been available commercially for decades, but didn't receive any response. Seems like a vanity/prestige publication to me, perhaps a way for Sony to advertise the high-speed capabilities of its cameras.
In my opinion, the insight is this:
> express in piano playing were perceived as intended by both pianists and musically untrained individuals
Obviously pianists have known this for more than a century. But do average listeners hear the same "thing"? It's a question worth asking.