Underlying decision making processes on Iowa Gambling Task

Iowa Gambling Task (IGT) assesses decision making in uncertain conditions. Several studies have reported impaired performance on IGT in various clinical population compared to healthy normal. However, some researchers have reported incongruent findings from the basic assumptions of IGT in healthy normal. Our aim was to examine the possible decision making processes on IGT.

The IGT was administered on two groups: Healthy normal (n = 34) and offspring at high risk for alcoholism (n = 34). Subjects were matched on age (+/-1 year), education (+/-1 year) and gender. Other tools used were: Mini-international Neuropsychiatric Interview, Family Interview for Genetic Studies, Socio-demographic Data Sheet, Annett's Handedness Questionnaire.

Results showed a significant difference between two groups on selections made from disadvantageous deck A but no significant difference on disadvantageous deck B, advantageous/safe decks C and D. Also, there was no significant difference between two groups on IGT Net score [selections from decks (C + D) - decks (A + B)]. Further analysis showed that varying nature of reward and penalty schedules play an important role in selecting the cards from four decks of IGT. Subjects may prefer infrequent penalty decks without consideration of delayed loss/gain.

Frequency and magnitude of reward/penalty in IGT may adversely impact decision making. Deck B can induce myopia for delayed loss in the healthy normal too because of having a high frequency of gains with high magnitude of reward. Hence, IGT related studies should consider these factors while making an inference about decision making ability.