When we are startled we react in much the same manner. We gasp in a breath of air and tense our muscles when we are startled. The tension is what holds the air in, and once that is gone the air comes back out as involuntarily as it went in. In other words, we laugh. I think much of the appeal of magic, and indeed, why most magic works, is because it startles us.
Babies love to be startled.
So many games we play with infants revolve around startling them peek-a,boo, gotcha, etc. It titillates them and makes them howl with laughter. And we like it, too. There's no question that audiences like Avner. At last year's FISM convention in Yokohama, Japan, he appeared on the final night's gala show.