erdnase thought card

[Guest]

I debated whether or not to post this in the close up thread or here under mentalism. In the end, however, it seems to me that the skills needed for this method of determining a card merely thought of belong in the arsenal of a mentalist.
The question is this; In Expert at the Card Table, Erdnase gives a handfull of methods for determining the identity of cards that are mertely thought of by a spectator. I'm curious about the method whereby the performer raises cards one at a time off the top of the deck and asks the spectator to merely think of one as the faces of the cards are flashed. The performer is supposed to watch for the moment when the spectator's eye's loose interest or relax, indicating that a selection has been made. For those of you with the text handy, this is listed as method "D" under "methods for determining a card thought of". Erdnase declaires that "this cunning and absolutely unfathomable strategem must have been devised by an individual of truly Machiavelian subtlety". The question is this. Does anyone out there make use of this strategy, and have they found it to be reliable? Any tips and additional sources would be appreciated.

Many thanks,

Jer.