The purpose of this study was not made totally explicit at the beginning of the experiment. You were told that the experiment investigated whether or not participants appeared to possess psychic abilities and whether or not participants' level of psychic ability correlated with their real life experience of psychic phenomena. This was a cover story...
The order in which the cards appeared on your screen was not totally random: it was dictated by a complex sequence. The experiment was designed to investigate whether participants are able to unconsciously pick up on this complex sequence and perform above chance on the task accordingly. The experiment also aims to investigate whether or not reports of psychic experiences in the real world are predicted by ability to unconsciously pick up on sequences in card order. If reports of psychic experiences in the real world are predicted by this ability, then it might suggest that spontaneous psychic experiences are underpinned by the ability to pick-up on patterns in the every day world.
If you require any further information or are interested in the overall findings of this study, then please drop me an email.