Tristan [Harris] told me James would show me what it meant. I’ll give you one example. When we sat together, James showed me a standard pack of cards. He said: See? Some of them are red, and some of them are black, and they are all mixed up together. Th en he turned the cards so the colours were facing towards him, and I couldn’t see them any more. He told me he was going to get me to sort them neatly into two piles – one black, one red – without me ever getting to look at the colour of the cards for myself.  
It was, obviously, impossible. How could I sort cards I couldn’t see?
He told me to look into his eyes, and – entirely using my own free will – to tell him whether to put the next card into a pile on the lef t , or a pile on the right. So I gave him my orders – lef t , lef t , right, and so on – according to what I was conf i dent were my own random whims.  
At the end, he lif t ed up the piles of cards and showed them to me. Th e red cards were neatly in one pile; the black cards were in the other.
I was baf f l ed. How did he do it? He eventually told me he had been subtly guiding my choices. He did it again, and said he would do it a little more crudely this time, to see if I could spot it. Finally – and he had to be pretty blatant – I saw it. When he told me to pick at the next card, he indicated very slightly with his eyes to the lef t or to the right – and I always chose in the way he unconsciously guided me to. Everyone always does, he told me