Well, yes.  We’ve known for a while now that we can read and recognise neurological states and patterns in the brain that are associated with the act of ‘recognition’.  Ie: When we present a stimuli to a participant – we can use EEG to read – completely bypassing the participants intent and consciousness – whether or not they recognise the stimuli – ie: have they seen this before.  This has been referred to in the popular press as ‘fingerprinting‘ and presents interesting philosophical and legal quandries – since it might potentially be used as a method of establishing facts in a trial situation.  For example:

“You say you had never been in the bank’s vault before – but, Mr Smith, when we showed you pictures of the vault interior – we saw clear evidence of recognition – which suggests you HAVE indeed been inside the vault.”

Piece of cake.  Look for the P300 ERP using any off the shelf EEG system.

But, as another example of how potentially ‘game-changing’ commercially available EEG sytems (such as the emotiv) are, it has now been suggested that you can actually carry out this same procedure with a $200 piece of plastic you can order over the web and is commonly used by gamers.  And specifically – you can ‘hack’ the person’s brain and dig out information such as passwords from a person’s brain.

Interesting.

Check out an article on the subject here, or for a bit more detail, here.