Lofty. That's what it was. Yes, absolutely.

His laughter could only be described as such. It came out and rose and fell at the same pace and in the same manner which one sees most often in the jaunty descent of an adolescent on stairs. The slight rise onto the ball of their foot before ultimately dropping down the next stair and rise-drop-rise-drop. It sounded natural enough. It wasn't forced -- the other end of the phoneline must be at least moderately clever. Probably some topical humour - work gossip, the inconvenient weather, some amusing anecdote from the morning. It wasn't genuine, though.
But I don't know in which way. It happened. It was lofty, not imaginary. It took place, there are at least three parties who could validate the laugh's existence. He'd wanted to laugh for whoever was listening. Does that make it genuine? Perhaps not every joke deserves a knee-slap and guffaw, he laughed to accommodate the amount of hilarity. Is it ingenuine because it wasn't that funny?

No. That doesn't make sense.

Is laughter not just a preferable form of social interaction? By laughing, was he not just maintaining social etiquette which, if done properly, has the same effect as involuntary belly-shaking laughter anyway?

I suppose it doesn't matter. Just so long as the sing-songy loftiness continues, society shall not collapse upon itself.