Sichuan pepper is responsible for neurological dissonance. It’s of the citrus family and is a ‘false pepper’.

It creates a numbing sensation and when used with chili peppers of moderate heat, it tricks the mind into thinking that it’s hotter than it really is ..the tingling and numbing sensation leading to the nervous system trigger the same responses as though you are eating something excessively spicy and hot.

I want to say..maybe a rush of endorphins. If you had just the Sichuan peppers alone, there would be no spiciness or heat. Just numbing and tingling. It’s a neat hack.