Construct Validity of the Iowa Gambling Task
The Iowa Gambling Task (IGT) was created to assess real-world decision making in a laboratory setting and has been applied to various clinical populations (i.e., substance abuse, schizophrenia, pathological gamblers) outside those with orbitofrontal cortex damage, for whom it was originally developed. The current review provides a critical examination of lesion, functional neuroimaging, developmental, and clinical studies in order to examine the construct validity of the IGT. The preponderance of evidence provides support for the use of the IGT to detect decision making deficits in clinical populations, in the context of a more comprehensive evaluation. The review includes a discussion of three critical issues affecting the validity of the IGT, as it has recently become available as a clinical instrument: the lack of a concise definition as to what aspect of decision making the IGT measures, the lack of data regarding reliability of the IGT, and the influence of personality and state mood on IGT performance.