Iowa Gambling Task(IGT)
Introduction
The Iowa Gambling Task is a task to study decision-making processes, i.e. it models the development of everyday life long-term profitable strategies against satisfying a need, in this case earning money.
The original Iowa Gambling Task studies was designed by Bechera and colleagues, 1994. The participant needs to choose one out of four card decks (named A,B,C, and D). The participant can win or loose money with each card.
Iowa Gambling Task
Deck A
Deck B
Deck C
Deck D
ChooseABCD
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The original scheme
In the original paper (Bechera and colleagues, 1994), the following procedure was followed:
- There were 4 decks of cards (A, B, C, and D)
- Participants had to choose in total 100 cards, one at the time
- Each time they choose a card, they get feedback about winning and/or loosing some money
- Participants did not know what each card would yield in advance (i.e., like a lottery)
- Participants started with a "loan" of of $2000 and were told to make a profit
- Decks A and B always yielded $100
- Decks C and D always yielded $50
- For each card chosen, there is a 50% chance of having to pay a penalty as well. For decks A and B, the penalty is $250, whereas for decks C and D it is $50.
About this implementation
The original paper used real cards, whereas nowadays, the Iowa Gambling Task is often computer based.
The basics are the same except that this is an online experiment. Instead of four decks of cards, you now see four "buttons" like on a slot machine labeled A, B, C, or D.
Analysis
When you are analyzing the data, you need to think carefully about what exactly you want to find out.
One interesting outcome is how often people decided for the "high risk" decks (A/B) or the "low risk" decks (C/D).
Another interesting question is how long it took people to decide before they made a low or high risk decision.
"Decks A and B are disadvantageous in the long run because they cost the most in the long run, while decks C and D are advantageous because they result in an overall gain int he long run." (Bechara et al., 1994, p.10).
Others
The task was originally developed to detect problems patients with damage to the ventromedial prefrontal cortex. This part of the brain is, among other things, involved in processing risk, fear, emotion, and decision making:
Following damage to the ventromedial prefrontal cortex, humans develop a defect in real-life decision-making, which contrasts with otherwise normal intellectual functions. Currently, there is no neuropsychological probe to detect in the laboratory, and the cognitive and neural mechanisms responsible for this defect have resisted explanation. Here, using a novel task which simulates real-life decision-making in the way it factors uncertainty of premises and outcomes, as well as reward and punishment, we find that prefrontal patients, unlike controls, are oblivious to the future consequences of their actions, and seem to be guided by immediate prospects only. This finding offers, for the first time, the possibility of detecting these patients" elusive impairment in the laboratory, measuring it, and investigating its possible causes.
— Bechara et al. 1994