The Iowa Gambling Task

The Iowa Gambling Task, demonstrated human’s capacity to know something before they are consciously or logically aware of it. In this experiment there were four decks of cards, two black and two red. These were presented face down and the player was given $2000 play money. The object of the exercise was for the participant to make as much money as possible by turning over cards, one at a time, from any of the decks. The cards would instruct the participants as to whether they had won or lost money. Unknown to the player the decks were rigged. Two decks were high-risk; they had bigger payouts and penalties resulting in a net loss. The other two decks were conservative with smaller payouts and penalties but resulted in a gain. The researchers found that participant ‘turning over of cards’ at the beginning of the task was random and on average players turned over fifty cards before choosing to draw solely from the lucrative decks and about eighty before they could explain why they chose those decks. On average participants were intuitively aware long before they were cognitively aware.

One of the Iowa Gambling Task researchers was Antonio Damasio. He was specifically researching emotion and had connected participants to a machine that measured electrical conductance of their skin while they were playing. The theory was that higher levels of conductance signal are associated with nervousness and anxiety (emotions) and that the participants would show conductance fluctuations in relation to their feelings towards the deck of cards from which they were about to select a card.

The researchers found that participants recorded readings as their hand approached the negative deck after turning about ten cards. In other words participants were physiologically aware of the situation at 10 cards. This was long before their external behaviours demonstrated awareness (fifty card turns) and even longer before their externally expressed consciousness which took over eighty card turns.


Bechara, A., et al. (2005). “The Iowa Gambling Task and the somatic marker hypothesis: some questions and answers.” TRENDS in Cognitive Sciences 9(4).

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