Iowa gambling task

Participants are presented with four virtual decks of cards on a computer screen. They are told that each deck holds cards that will either reward or penalize them, using game money. The goal of the game is to win as much money as possible. Unbeknownst to the participant, the decks differ from each other in the balance of reward versus penalty cards. Thus, some decks are "bad decks", and other decks are "good decks", because some decks will tend to reward the player more often than other decks. Participants are not told that the two "bad" decks have larger rewards and larger or more frequent penalties. On balance, the penalties in the "bad" decks outweigh the higher rewards they give. Therefore, participants should choose the decks with smaller rewards, as they will also give significantly fewer penalties and give a better long-term payout. By contrast, patients with amygdala lesions never develop this physiological reaction to impending punishment. In another test, patients with ventromedial prefrontal cortex (vmPFC) dysfunction were shown to choose outcomes that yield high immediate gains in spite of higher losses in the future. Bechara and his colleagues explain these findings in terms of the somatic marker hypothesis. The Iowa gambling task is currently being used by a number of research groups using fMRI to investigate which brain regions are activated by the task in healthy volunteers as well as clinical groups with conditions such as schizophrenia and obsessive compulsive disorder. ==Critiques==

Although the IGT has achieved prominence, it is not without its critics. Criticisms have been raised over both its design and its interpretation. Published critiques include: • A paper by Dunn, Dalgliesh and Lawrence • Research by Lin, Chiu, Lee and Hsieh, who argue that a common result (the "prominent deck B" phenomenon) argues against some of the interpretations that the IGT has been claimed to support. • Research by Chiu and Lin, the "sunken deck C" phenomenon was identified, which confirmed a serious confound embedded in the original design of IGT, this confound makes IGT serial studies misinterpret the effect of gain-loss frequency as final-outcome for somatic marker hypothesis. • A research group in Taiwan utilized an IGT-modified and relatively symmetrical gamble for gain-loss frequency and long-term outcome, namely the Soochow gambling task (SGT) demonstrated a reverse finding of Iowa gambling task. Normal decision makers in SGT were mostly occupied by the immediate perspective of gain-loss and inability to hunch the long-term outcome in the standard procedure of IGT (100 trials under uncertainty). In his book, ''Inside the investor's brain'', Richard L. Peterson considered the serial findings of SGT may be congruent with Nassim Taleb's suggestion on some fooled choices in investment. ==References==