Twirling isn't the only way to eat spaghetti?

You're right, Italians and many, many other people absolutely forbid the practice. Marcella Hazan, in The Essentials of Classic Italian Cooking, says, "Do not break up spaghetti or any other long pasta into smaller pieces." Many other Italian cookbooks we checked make no mention of the practice, presumably because the barbarity of it never crossed the writers' minds.

The word spaghetti means "thin cords" in Italian, and although there is a diminutive version available - spaghettini - it refers to the diminished thickness of the strand, not in any way the shortening of its length. It is probably fair to say that if the Italians had intended for you to eat short pasta, they would have made it shorter for you.

Ochef, we often come out on the side of free will (at least as regards cooking), and though you might go straight to Italian cooking hell, we support your right to break spaghetti in half before cooking.

The folks at Cook's Illustrated actually give instructions for breaking pasta in half neatly (Sept./Oct. 1999), and if that doesn't constitute permission, we don't know what does. (Actually the Cook's Illustrated writers say they don't usually break strands of pasta they intend to eat with sauce, but often do break them for inclusion in casseroles.)

We know of no scientific study that has addressed any taste ramifications of breaking spaghetti in half. We would surely never acknowledge the practice ourselves. Even if we had ever done it. Which we almost certainly have not.