The electricity’s already halfway down your arm. Your body began to act a full half-second before your conscious self ‘chose’ to, for the self chose nothing; something else set your body in motion

What is this from?

I remember, years ago, hearing part of a (I think) Radiolab episode that was about this… Something about how our brains send the signal seconds before we’re conscious of the thing, but I was never able to find the full episode after (and I definitely looked).

Anyone happen to know what episode I’m referring to, or did I hallucinate the entire experience?