Reexamining the Validity and Reliability of the Clinical Version of the Iowa Gambling Task: Evidence from a Normal Subject Group

Abstract

Over past decade, the Iowa gambling task (IGT) has been utilized to test various decision deficits induced by neurological damage or psychiatric disorders. The IGT has recently been standardized for identifying 13 different neuropsychological disorders. Neuropsychological patients choose bad decks frequently, and normal subjects prefer good expected value (EV) decks. However, the IGT has several validity and reliability problems. Some research groups have pointed out that the validity of IGT is influenced by the personality and emotional state of subjects. Additionally, several other studies have proposed that the “prominent deck B phenomenon” (PDB phenomenon) – that is, normal subjects preferring bad deck B – may be the most serious problem confronting IGT validity. Specifically, deck B offers a high frequency of gains but negative EV. In the standard IGT administration, choice behavior can be understood with reference to gain-loss frequency (GLF) rather than inferred future consequences (EV, the basic assumption of IGT). Furthermore, using two different criteria (basic assumption vs. professional norm) results in significantly different classification results. Therefore, we recruited 72 normal subjects to test the validity and reliability of IGT. Each subject performed three runs of the computer-based clinical IGT version. The PDB phenomenon has been observed to a significant degree in the first and second stages of the clinical IGT version. Obviously, validity, reliability, and the practice effect were unstable between two given stages. The present form of the clinical IGT version has only one stage, so its use should be reconsidered for examining normal decision makers; results from patient groups must also be interpreted with great care. GLF could be the main factor to be considered in establishing the constructional validity and reliability of the clinical IGT version.

Performance on the Iowa Gambling Task: From 5 to 89 years of age.

“…Examination of performance in children represented an extreme and shows that some populations are clearly distinguished from normal adults: Children appear homogeneous as an age group yet display anomalous and inconsistent decision making. Variability in responses occurred in all age groups except children, and every group utilized some degree of frequency bias, consistent with critiques by Lin, Song, Chen, Lee, and Chiu (2013). Nevertheless, frequency bias could not account for all age-related variability, especially variability between children and adults.…”

Decision-making of Prefrontal Patients with the Iowa Gambling Task: Unexpected Spared Performances and Preliminary Evidence for the Need of Alternative Measures

“…Lin et al, 2013). In addition, if we consider each kind of deck separately (bad: A vs. B; good: C vs. D), it appears that controls selected more cards from the infrequent-loss decks (B and D).…”

“…Therefore, we also considered the GLF score, calculated by subtracting the number of choices from the low-loss (B + D) and the high-loss (A + C) frequency decks (e.g. Lin et al, 2013). Consistent with existing literature, the task was divided into five blocks containing 20 cards each to provide information about how the pattern of choices might change across the course of the task (Bechara et al, 1994).…”

“…Chiu et al, 2008), calculated by subtracting the number of choices from the low-loss frequency decks (B + D) and the high-loss frequency decks (A + C) (e.g. Lin, Song, Chen, Lee, & Chiu, 2013). There is evidence that GLF can be the primary variable affecting the decision-making choices, both in normal (e.g., Horstmann et al, 2012) and in clinical populations (e.g., Martino, Bucay, Butman, & Allegri, 2007).…”

Are Normal Decision-Makers Sensitive to Changes in Value Contrast under Uncertainty? Evidence from the Iowa Gambling Task

“…This suggests that performance in the IGT is dominated by a gain-loss frequency, rather than by value and long-term outcomes [13]–[16], [23]–[27].…”