Week 7

The Iowa gambling task and the somatic marker hypothesis

The somatic marker hypothesis (SMH) describes a theory, suggesting that cognitive processes such as decision making can be highly influenced by emotions. One way this hypothesis can be tested has been explained in an article by Bechara et al. (1997) using the Iowa gambling task (IGT). The IGT is a relatively simple decision-making experiment, using rewarding and punishment as consequences for participants decisions. Here, participants have to choose several cards from 4 different decks of card, 2 of which are “good decks” and 2 of which are “bad decks”. Bechara et al. found a significant learning effect, showing that after few trials, healthy participants would choose the good deck rather than the bad one. Additionally, throughout the task, skin conductance response (SCR) was measured, showing a significant increase during more risky decisions.

Patients with lesions in the ventromedial prefrontal cortex (VMPC) failed to monitor such SCRs. Moreover, there was no evidence of a learning effect but a rather deficient way of playing was displayed. These findings supported the SMH, suggesting that patients with VMPC damage have impaired emotional progressing and therefore returned to decks with bad outcomes sooner as normal patients. Their decisions were found to be mainly based on the most recent outcome whereas normal participants managed to learn from their overall experience of all past trials. (200 words). When forming a decision, the brain receives emotional-related marker signals that can be unconscious or conscious, helping to form an adequate decision.

These findings have been supported by Maria and Mc Clelland (2004), who used a replication of the IGT, but did not monitor the SCRs of normal participants or patients. This has been highly criticised by Bechara er al. (2005), since the failure of VMPC damaged patients to display such SCRs stays to be an outstanding mystery. Bechara et al. (2005) argues that rather than not showing SCRs, VMPC damaged patients should rather show an even stronger one, since based on their decision through knowledge and their inner gut feeling seems to form distinct decisions. This would be an interesting area fro further research.