Telepathy

Tonight I saw the kids we went flower hunting and then to the pub. Gemma got out a pack of playing cards and said "Daddylah I'm going to demonstrate the power of telepathy between me and Jamie."
Yeah yeah yeah yaddy yaddy yaddy.
"No really we found this out by accident last week, Jamie can read my mind."
"OK what's the trick?"
"There's no trick daddylah. Look you just choose a card any card and show it just to me. Then I'll ask jamie to choose it by the power of telepathy."
Yeah Yeah Yeah!So I chose a card and showed it her. 8 of clubs. She lay down the cards on the table and started asking Jamie "Is this the card?"
"NO!"
"Is this it?"
"No." she pointing to the cards as she asks.
Eventually she points to the card I chose and he hesitates and says "Yes."
I'm gob smacked. I try and remember what she did. Did she scratch her nose before he said "yes"? Did she make a signal then they counted a certain amount of cards until he had to say "Yes"?
I demanded that they do it again.He got it right again.
I demanded a third trial. I changed the rules a little, he still got it right. I watched her like a hawk looking for tell tale signals she might have made. But nothing was spotted.So now I'm at a loss to know how they did it. Gemma insists it's telepathy. I credit my children with enough intelligence to pull a fast one on me. But I confess I haven't a clue how they do it.
Damn it's hard having kids smarter than you.